vk5fnet

Retiring this call sign

2011-07-18T14:59:00.004+09:30

Well, the call sign is a little over three years old. VK5FNET.

It has served me well, however I must move on, my new callsign has been allocated.

Study for license upgrade nearly complete

2011-06-26T17:50:00.003+09:30

I have been studying for the Standard license upgrade course with Paul Hoffman, VK5PH, for the last three months. 12 weeks on a Tuesday evening with a dozen other hopeful students.

Well the last class was last week and I have a few things I need to re-read. Given my results on the in class practice exams, Paul has suggested I actually sit the Advanced theory first instead of the Standard theory. On the Advanced practice exam I would just scrape a pass mark. Not confident enough just yet. Good news is I am pretty confident about getting 90+% for the Standard theory and the Regulations.

The exam in this coming weekend. So I have to make up my mind about which exam to sit. I would love to do the Advanced and be done with it.

I have a couple of topics that I am not confident yet, mainly Valves, transmission lines and antenna loading. I have four nights free this week, so I will read up and see how things go =)

The really hard part is choosing to let the ACMA/WIA give me the next available callsign or choose one of my own. $5 or $20 respectively. Decisions, decisions...

Kim VK5FNET

Big trouble in little Corolla

2011-06-26T17:31:00.006+09:30

The little Corolla has been getting steadily worse in the starting on cold morning. Saturday it stopped working all together. Hey I can use a screwdriver and sand paper! This looks easy, the internets tells me this is a common problem with Corollas and is a twenty minute job. Famous last words!

So, after disassembling the solenoid on the starter motor of the car, including un-soldering the solenoid winding from the cap. I cleaned the main starter motor contacts. They were a mess, so I sanded them back and tried to clean all the black gunk off. I cleaned all the other conductors and reassembled. As you do...

Then bolted the starter motor back in the car, tried to start it. Nothing.

Thinks.

Fiddle around with key switch wiring, contacts, etc etc ... nothing. There was only 6 volts on the ignition key switch to the solenoid. Not sure if there is lots of lossy connections between the battery, switches etc. Bother.

Find battery is a bit low on the volts. Put the battery on to charge, went over to a friends place for diner. Got home, the battery seemed to be charged suitably. Went to bed.

Got up this morning, to ponder the issue of there not being enough volts on the ignition wire, scour the internet for more ideas. Walk to servo to find a relay and connectors, etc. They had nothing. Zip. Bother...

Go home, listen to the WIA broadcast and ponder other possible solutions.

After a couple of phone calls shuffling my calendar, I walk half an hour into town to find Sprint Auto to find these parts. Sprint Auto was closed. Was not liking my luck at this point. Walk to Repco. \o/ Its open! Speak to geezer about what my problem is and what I thought might be a suitable solution about not enough volts on the key switch. He suggested that it sounded reasonable, but I would be better off waiting until tomorrow to find an auto-electrician or get a reconditioned second hand one. I needed the car running today. Things to do. With a lighter wallet and a pocket full of parts I walked half an hour home.

Got home grabbed some lunch, had another look on the internets to see if I could find someone else with a similar problem or at least a circuit diagram and repair manual type information. At this point I knew there was something that I did that was amiss. Couldn't quite put my finger on it.

Build up a relay that is trigger by the ignition swith from the key, powering the solenoid from the battery direct to get more current through to pull the solenoid in. The solenoid wasn't moving, but the motor was turning. This was very, very wrong.

Realize that maybe the solenoid was actually dead, maybe a broken winding. Decided to pull the starter motor off the car and ponder some more. I couldn't actually find anything on the Bosch model at all. There were a lot of NipponDenso models that looked similar. At this point I started comparing any starter motor for the 4A motor I could find. At some point I noticed that the large contact studs on the back of the solenoid were wrong. The short stud was on the top, away from the motor and the long stud was on the bottom, closest to the motor and connected to the positive cable for the starter motor. Hang on a second...

So at about this point I looked at a service manual for an AE86, which is a different model, but gave me the most detail for an 1988 corolla I could find. The schematic on the AE86 go me thinking about why the motor was spinning without engaging the solenoid. You got it, I had put the thing in upside down and solder the wires in back to front in the circuit.

After another half an hour, I had assembled it the right way and put it back in the car.

Not expecting it to even move the solenoid, the car car started smoothly and ran! So I switched it off and added my ignition relay, and that started nicely too. So I tidied everything up and took the car for a lap around the block, to be sure.

Half hour job, eight hours later! At least its working properly now and we can now go do those things we need to do. =)

Kim VK5FNET

recycled steerable dipole

2011-05-02T18:48:00.003+09:30

I rescued an old teevee antenna from Karl before he escaped the state. (he has gone to vk7 land).
it had a number of 'large' elements on it for VHF and lots of small elements on it for UHF. =D

I striped all the elements off the boom and started looking at useful arrangements using the longest ones. did some numbers and worked out that i could use the largest and third largest elements and reuse the 'egg' insulators for a reflector element, then wrap an inductor around the 'egg'.... =)

Did the measurements, rough numbers for the coil, should be good for the middle of 10 meters. \o/
Put it together, then spent the rest of the afternoon cutting firewood. consequently I ache all over! =/

So after the pot-belly stove is fired up and the dinner is on the boil, I test the antenna to see where in the 10 meter band it works ok.

So it fails as a dipole for 10 meters. Rather badly actually the SWR > 5:1 across the whole band =(
Not to be discouraged I tested it on 15 meters. Bingo! The SWR < 1.5:1 across most the band. \o/

So lesson for today, is my modeling/measuring concept is right out. However the consequence is that if I tinker with the coil I should be able to find a tap point suitable for 10 meters. A job for next weekend though.

I

I've added some images of the process and what the final center and loading coil looks like.
It is not particularly self supporting, as the final elements are much longer than the original teevee antenna.

73,

Kim VK5FNET

Listening for Yuri's day ...

2011-04-18T15:09:00.004+09:30

I was organised, got the ALICE pack all setup to record the commemorative transmission on the 12th and again on the 13th.

I listened for many passes ... Not a peep =(

Anyhow, found this today;

"The planned operation of ARISSat-1/RadioSkaf-V/KEDR on April
11 and April 12 from inside the International Space Station
as part of the commemoration of the 50th anniversary of Yuri
Gagarin's flight was not successful. No earth stations on
the ground reported hearing transmissions on the ARISSat-1
downlink(145.950 MHz for FM analog/145.920 MHz for digital).
The planned retransmission of the satellite's FM downlink
via the Kenwood TM-D700 transceiver --currently used for
ARISS contacts--was also not successful as no reports were
received of signals heard on 437.550 MHz. However, a
similar ARISSat-1 transmission test conducted in February
was successful, with 145.950 MHz signals being successfully
received by several ground stations. "

ANS-104 ANS Special Bulletin - ARISSat-1 Not Heard During Gagarin Commemoration

Exciting developments in GNU Radio

2011-03-03T09:49:00.002+10:30

The article; Exciting developments in GNU Radio, describes updates to the GNU Radio project.

I wonder if this can tie in to the SDRCube project that Erich VK5HSE has been tinkering with?

73, Kim

Land of Lisp

2011-01-12T10:54:00.003+10:30

I have been getting into Lisp recently. Quicklisp has made the process a fair bit easier, so I took the plunge and ordered a copy of Land of Lisp.

What do I want to do with Lisp? Well the main reason is that I used to code in Lisp back at Uni. I would like to do some log processing and sensible matching against multiple rule sets. However I suppose the idea that Land of Lisp is learning Lisp through creating games was quite an attractive idea.

Kim VK5FNET

New key

2010-12-27T22:04:00.003+10:30

This chrismas I received a key! Along with a vintage power supply and Morse sounder. It looks old and has some loverly green corrosion on most the brass bits. It sits atop a wooden base and that atop a steel slab with a rubber sheet glued beneath. It has PMG stamped on the front of the wooden block. Should scrub up well. Would like to find out more about when and where they were used. Will post pictures soon.

OSDC trip

2010-11-29T20:48:00.005+10:30

This last week I flew off to Melbourne for the Open Source Developers Conference. I spoke to many people about a wonderful range of topics. The main things that I was aiming to be across was large or enterprise installations of any CMS that folks have experience with. There are a surprising number of options. Drupal came up many, many times. Varnish with one of Apache + mod_php or Nginx + FastCGI seem to be a common platform.

Although there were a couple of good Perl talks too; Schwern's Perl5i and Damian Conway's talk on Quantum Mechanics + General Relativity + Perl. Reading several of Richard Feynman's books in the last year certainly helped to keep on the same page as Damian as he galloped along with some complex ideas. The talk "git for age 4 and up" was great, certainly cleared up my misconceptions of labels in git =)

73, Kim

Monthly update, November

2010-11-17T20:38:00.005+10:30

Well its been a little while since the last update and I've been busy. AHARS has been quite active, the good weather has brought about many good events.

The AHARS Symposium. Was a great day, its amazing that as I keep reading and tinkering that little nuggets from the talks start to fall into place. Little bits of wisdom finally making themselves understood. There was just so much to take in on the day... Note the microwave gear on the right hand table, along with the VK5TR loop, and HPSDR rig at the lower right corner.

We had the National Field Day. So I helped out at the AHARS tent. To aid publicity AHARS got a foot in the door of the Eden Hills Primary School Strawberry Fete. Its your usual spring fair; food, plants, books, cloths, stuff, junk, treasure, etc etc...

The great resistor packing day for AHARS. Folks in the club thought it wise to do a bulk purchase of resistors so that all the constructors, repair and homebrew folks had adequate parts in their respective junk boxes. I decided that I needed to stock up too, so I ordered a box. The bulk order was made, around 1.2 million resistors in all. The day finally came, we assembled and sorted out each 'decade', cut 100 of each value, then assembled a bundle of each of the 12 values into a roll, then each roll into a box. Thankfully many extra volunteers participated for a good day. Lots of radio talk. I learned a thing or two about boat anchors. Went home with a box of resistors =)

The AHARS Buy and Sell. I was up very early to help setup for the Buy'n'Sell. There was an amazing array of stuff. Old radio gear, new radio gear, test gear, computer stuff ... I picked up a few things.

With the holidays coming up, I hope to get more done...

73, Kim

Wireless Networking in the Developing World book

2010-10-26T13:10:00.005+10:30

At lunch I was browsing through some old email and was reading some "help me learn about OLSR" type conversations.

There was a link to the book; Wireless Networking in the Developing World

Its now in second addition and in now translated to more languages, you can download it or buy it.

It has been a while since I have setup up new WiFi infrastructure. My network at home has been pretty stable. I should go see whats new in the second edition...

73, Kim

National Field Day 2010

2010-10-24T09:05:00.010+10:30

Yesterday being the National Field Day - NFD for 2010 in VK (Australia), I spent with the Adelaide Hills Amateur Radio Society.

AHARS setup a tent at the Eden Hills Primary School Strawberry Fair.

A number of contacts was made on HF and 2meters and 70centimeter. Some contacts were made through the cross band repeater on the project horus ballon, launched to coincide with the NFD.

I spoke to about a dozen people across the day and handed out pamphlets. That doesn't sound like many people, but there were at least six club members there across the day, who each spoke to members of the public across the day about Amateur Radio and the club activities.

There were a couple of themes across the day for me. The main one was the grey nomads, who use the travelers nets to update their location and journey progress with their net controllers, mainy for safety, directions and recommended stop overs. Folks who use UHF CB and or the four wheel drive net VKS737 already. It was interesting to see them explore the options that Amateur Radio could give them. Even if it was only a couple of more bands to listen to the various travelers nets and listening to the reports coming in about traffic congestion, etc. Its not something that I've really put a lot of thought into, but certainly created an awareness for me about how folks outside of amateur radio use radio and why.

Secondly was the HF verticals and how to set them up with automatic tuners, especially across multiple bands. I believe the original squid pole article was from VK3JJ in AR, but I will have check that. A few of the AHARS club members present had built up the JJ antenna and all spoke about issues with tuning and assumptions with measurements and materials. There is certainly a lot of room for experimentation and of course careful measurement - a topic that comes up so frequently, which of course lead on to the third theme for me... upgrading my license.

I spoke to several folks about upgrading my license, the study involved and stratagems for learning. All duly noted. I will be pulling my finger out over the summer break.

I bumped into a few old friends, picked up a few books and plants at the fair. Saw a new part of Adelaide that I hadn't seen before. Over all, even with a little sunburn, I enjoyed the day.

73, Kim

Copper cactus J-Pole - part 1

2010-10-17T21:15:00.003+10:30

For some time I've been wanting to get a decent antenna up for 2 meters. We have a good technical 'net on a Monday night by the AHARS guys. I used to regularly join in but my little HT's batteries died and it doesn't work without them. I do have a little 1 watt Kenwood rig and a 4AH 12volt battery, which works a treat. However the antenna situation is letting it down. It works quite well on receive, but I need to get the antenna up much higher to activate the repeater.

Quite some time back, I was given some scrap aluminium and a 2 meter slimjim. I used the slimjim alot. It was pretty fragile and I repaired several breaks from wind damage, but its just not very practical as a portable antenna for the rallies, eg ROSA or as a home base antenna.

Lots of digging on the Internet yielded lots of info on the copper cactus antenna. I didn't have any of the common materials, so a visit to the local hardware stores didn't have any hard drawn copper pipe either. Well, Home Hardware had six meter lengths of 1/2" for $98 and did not cut off lengths either =( I decided that a copper cactus was going to be out of my reach and put it off.

Then I picked up a little dual band 2m/70cm 3/8" screw on to mag mount antenna for the car, just before the rally. Its ok pootling around on the car, but with out any ground, it doesn't perform on the little Kenwood at home as well on receive as the rubber ducky on the HT. Its pesky to setup and use at home.

That was all some eighteen months ago. Since then Bunnings has opened and some of their stuff is cheaper than the other hardware stores. Bunnings also has more range, but quality varies greatly. However, they did have 1/2"/15mm and 3/4"/20mm hard drawn copper pipe, but only in 1.5 meter lengths. The HDCP 20mmx1.5m is $16 a length, with 20mm 90 degree bends $2, 20mm Tees $3 and one bag of 1" clamps/brackets $7. So last weekend I needed to get some other things from Bunnings, so I got all the bits I needed and some spare for future projects.

This evening I worked out the measurements and cut up, then sanded the pipe, bend and tee joiners. I have a little industrial hair dryer, which gets everything up to temperature and soldered the lot up.

What remains is the mounting to little mast and getting some coax set up to the clamps. Obviously matching and endless tweaking =)

Can't wait to get the antenna up and tested.

72, Kim

SolderSmoke 126.mp3 is out

2010-10-13T08:24:00.002+10:30

Yes, thats right, SolderSmoke is back \o/ Head on over, download, listen and enjoy. Damn just got up and have to hop on the bus right now, but I'll be listening to is ASAP!

SolderSmoke 126.mp3
October 11, 2010
SolderSmoke returns!
Shack #7: The New Shack
Drake 2-B inhaling RF
Listening to 75 AM and SSB: WA1HLR, KM1A
Time signal on 3820 +/-?
Repairing DaVinci Code QRSS rig
UK test gear works fine on this side of pond!
Computer woes: First Linux SolderSmoke
Astronomy from inside the Beltway
Winter SPRAT: Great info, philosophy, inspiration
Charging up solar cells
Inbound Boatanchors: DX-40, DX-60, HQ-100, HA-600(A), HT-37
MAILBAG

OSDC 2010 - First Draft Program

2010-10-12T13:41:00.001+10:30

The programme is up! Tentative, but up! http://2010.osdc.com.au/programme

Web Cams for Linux

2010-10-08T11:11:00.004+10:30

So as a result of a friend asking me about web cam support under Linux for a computer vision project, I found some interesting resources that I thought was worth sharing.

The Linux UVC driver and tools web site lists a couple of really cheap web cams like the Logitech Quickcam C150, which we can source locally for $18 at MSY.

So, some solid state storage, a usb hub and a tiny home server or decent wifi accesspoint with usb would be ideal for this project =)

73, Kim

Interesting power generation projects from the crew of HackerSpace Adelaide

2010-10-03T10:41:00.004+10:30

Paul, VK5FPAW, after a challenge from the Adelaide HackerSpace crew, has bee putting together a pedal power rig to power his HAM radio rig for the WIA WIA National Field Day on the October 23rd. Perhaps other HAM radio contents too, like the WIA Spring VHF-UHF Field Day is on November 20th & 21st. More events on the WIA Calendar.

Over at; http://picasaweb.google.com/pschulz01/PedalPower, Paul has a few photos of his pedal power rig. The stationary trainer is a nice way to mount everything. The alternator is a 50A Bosch. So far Paul has spent about $250.

I'm looking forward to hearing Paul, VK5FPAW/StationaryMobile on air on the field day ;)

73, Kim

New warning system for solar storms

2010-10-03T10:21:00.002+10:30

From the WIA broadcast news this morning;

WIRELESS WEATHER

NEW EUROPEAN SYSTEM GIVES WARNING OF SOLAR STORMS

Researchers at the University of Bradford located in the United Kingdom say that a new method of predicting solar storms that could help to avoid widespread power and communications blackouts has been launched. Amateur Radio Newslines Norm Seeley, KI7UP, says that up to now, solar weather prediction has been done manually with experts looking at 2 dimensional satellite images of the sun and assessing the likelihood of future activity.

But a team from the university's Centre for Visual Computing has created the first online automated prediction system using 3D images generated from the Solar and Heliospheric Observatory or SOHO satellite.

Already in use by both NASA and the European Space Agency, the Bradford Automated Solar Activity Prediction system also known by the acronym ASAP identifies and classifies sun spots and then feeds this information through a model which can predict the likelihood of solar flares. The system is able to accurately predict a solar flare six hours in advance and the team is working to achieve a similar accuracy for the prediction of major solar eruptions in the near future.

Solar storms involve the release of huge amounts of hot gas and magnetic forces from the surface of the sun into space at around a million miles an hour. The next major solar storms are expected in 2012-13 as part of the sun's 11-year weather cycle. A 2008 US National Academy of Sciences report estimated that modern reliance on electronics and satellite communications means a major storm could cause twenty times more economic damage than Hurricane Katrina.

Although major solar eruptions and coronal mass ejections normally take several days to reach the Earth, the largest recorded in 1859 took only eighteen hours. Solar flares which can also cause significant disruption to communications systems take just a few minutes. Because of this, advance warning is of vital importance to enable steps to be taken to avoid the worst effects of such solar activity.

Data recovered from the system is on-line at the European Spaceweather website;

http://www.esa-spaceweather.net/sda/asap/

The VK5 News: 3rd October

2010-10-03T09:40:00.005+10:30

AHARS
Saturday, 23rd October; National Field Day @ Eden Hills Primary School, Strawberry Fair
VK100WIA
Sunday, 7th November; AHARS buy and sell
2nd, 4th Friday; Lunch Blackwood RSL
JOTA 16th
More at; http://www.qsl.net/vk5bar/
VK5KC David

WICEN
9,10th foundation license
23rd October, Nat Field Day
20th, 21st November foundation license training
QRP CW @ Rostrevour Tennis Club
More at; http://www.sa.wicen.org.au/
VK5PH Paul

AREG
Friday 15th October; Meeting at the Reedbeds; Talk on coax cable, types, suitability, tools included
More at; http://www.areg.org.au
VK5BB Ben

Back to studying

2010-09-21T19:17:00.003+09:30

Well its been a while since I've regularly had a toasty soldering iron on the workbench. Well for that matter its been a while since I've had a workbench. I have a bench in the shed, but its been so cold and wet that it is really not any fun spending any time there. Also there have been some house renovations that have made space an issue, to the point that I boxed up a bunch of books. I put them "somewhere".

So last weekend I dug out those "missing" books and flicked through looking for ideas. I have some work to do and need to brush up on a number of things. I downloaded the standard and advance syllabus as well so that I can tick off all the topics once I've covered them.

I also picked up a couple of Drew Diamonds books on the week end at the symposium; Radio Projects for the Amateur, volumes 3 & 4. I have been wanting to get my hands on these for some time. They were the first homebrew books I laid eyes on, on the WIA book store. However funds have been an issue for a while so they have been out of reach. Gladly no more is that a problem =)

I've made it through the scary bills part of the year and will be saving up for the "tome" of radio theory from the WIA, Radio Theory Handbook for Amateur Operators (5th ed.) by Fred Swainston, along with EMRFD.

How ever the cost of these seems to sky rocket every year and the postage is becoming outrageous! Oh well, heres hoping that I'll get the reading material before the end of year break to read during those lazy days of summer when work closes down for a bit... Mabye even get the chance to get away for a bit to unwind and read.

In the mean time, I want to read Solder Smoke the book again.

There were some rather crafty ideas presented in there that I need to get my head around again. Need more time on the workbench tinkering. Core things being to straighten out the mutual coupling/inductance and the whole transistor holes thing in my head =) Most the other ideas work for me. I need to tinker with the math around power calculations too. I kind of get it, but nothing backs it up like doing. I figured out current limiting resistors on the last read through =) Also can't wait for Bill to get another SolderSmoke podcast out. Its funny I miss that more than any other regular release HAM radio news. Would be great if it was monthly even. I keep thinking about putting together a podcast, but am still too shy of a microphone.

73,

Kim

Word of the day: flum

2010-09-20T21:33:00.006+09:30

flum, v: to move or position an item on a quickly setting glue.

Yesterday I went along to the AHARS symposium. I had a wonderful time. The impact of the event probably won't be fully realised for some time yet. However, I took some notes and a few photos. Also will put together a couple of posts here about the symposium and ideas gleaned from it.

I like to write down words of phrases that I haven't heard before. 'flum' was one such word that I noted yesterday. Thank you to Drew Diamond, VK3XU, for extending my vocabulary. I have more notes to read through and plenty of googling to do =)

73,

Kim, VK5FNET

Exciting things at work

2010-09-16T09:13:00.004+09:30

There is much cheer here at work at the moment. This is the season for the anual University rankings and we did pretty well.

Also this week, I am working on posting the videos of OpenDay Blog from last month. We also put them up on our vimeo channel.

We've been pretty busy for a while and next week we are interviewing for another programmer. So its a happy time here after lots of work leading up to OpenDay and other campaigns we've been working on.

73, Kim

junk code

2010-09-10T12:34:00.000+09:30

Today I was tidying up my junk code directory. I cut this up one lunch time when I couldn't focus on the FTP server code I was bashing my head against - now sorted.

So, whats this for? There was a challenge a while back on the Brainwagon blog, using /dev/urandom to generate a list of 'random' characters to fit a pattern, ten blocks of five characters, each block separated by spaces.

This is used for testing cyphers and other fun stuff =) I spent some time when I was back in London working on some cypher and compression code. So I can vouch for the need for tools to generate large random sets - one time pads - that you can play back over and over to make sure that you reproduce that bug, with different versions of your code. Correctness was the issue at hand. Later came the performance issues.

So, Mark posted a "Unix/sh challenge". My brain needed a break and who can resist a bit lunch time shell coding? Well I tried and I got it pretty close. Anyway I decided to try a Perl version to see if I could make it easier to read, then make it faster.


#!/usr/bin/perl
my $limit = 10_000;
my @cypher;
while (<>) {
    my @chars = split(undef, $_);
    for my $char (@chars) {
        if ($char =~ m/[A-Z]/ ) {
          push @cypher, $char;
          if ($limit <= scalar(@cypher)) {
              my $offest = 0;
              while (@cypher) {
                  for (1..10) {
                      print "  ";
                      for (1..5) {
                          print pop @cypher;
                      }
                  }
                  print "\n";
              }
              exit;
            }
        }
    }
}

72, Kim

How small can you make antennae?

2010-08-31T09:45:00.005+09:30

When we talk about "small antenna", I think about the homebrew antenna I have made for WiFi devices on 2.4GHz.

Now, you can make Yagis for any frequency right? Right, so have a look at this; Antenna directs light at the nanoscale.

"Niek van Hulst and colleagues at the Institute for Photonic Sciences in Barcelona ... fabricated a number of nanoscale Yagi Uda antennas containing the tiny parasitic elements made from gold using lithography to etch the devices onto a glass substrate. The total length of individual antennas was 830 nm where individual feeds were just 145 nm, each separated by 175 nm."

73, Kim

Quote of the day by SKR

2010-08-10T19:24:00.004+09:30

I've been using this quote in my email for about seven or eight years;
"Art without engineering is dreaming; engineering without art is calculating." Previously I only had th initials; SKR

Today I found out that SKR is none other than Steven K. Roberts. Yes the creator of the Winnebiko and BEHEMOTH!

I started using that quote because it appealed to my inner geek. Especially after I saw a series illustrations from Janet Reid entitled; 'Renaissance Geek'

See the posts on the Make blog; Make it anywhere with a mobile lab;

Part 1

Part 2

Part 3

Part 3

AHARS Symposium September 19

2010-08-10T09:58:00.001+09:30

Event; AHARS Symposium

Topics; Amateur radio, Construction

Speakers; Drew Diamond VK3XU, Phil Harman VK6APH and more

Venue; Belair Community Centre, Corner of Sheoak Road and Burnell Drive, Belair

Cost; $20 at the door for morning tea, lunch and afternoon tea.

Date; 19 September, 2010

Time; 930am - 5pm

Voltage dividers for 5volt Arduino and 3.3volt SPI devices

2010-08-07T18:29:00.004+09:30

I am setting up a radio module to plug into an Arduino.
Specifically the RFM12B like in this schematic;
http://www.flickr.com/photos/jeelabs/3297526692/in/photostream/#/

The Arduino runs at 5volts and the RFM12B runs at 3.3volts. So I have to convert the line levels from 5v -> 3.3v on the inputs to the SPI device and from 3.3v -> 5v for the output.

The example has a 4K ohms and a 10K ohms resistor for the 5v to 3.3v voltage dividers for the Arduino output data lines into the RFM12B, does that sound reasonable?

I did the math and worked through the examples on the Arduino tutorial site and came up with the following values; 1.5K ohms, 2.2K ohms

72, Kim

usbsoftrock Ubuntu package, from the softrock40 group

2010-08-05T10:20:00.001+09:30

Seeing the very lengthy instructions posted recently for how to install a set of SDR software for Ubuntu, I thought I'd make a (very small!) start on reducing that complexity.

This evening I've packaged the first piece of SDR-related software in that set of instructions, usbsoftrock version 1.0.1 , for Ubuntu Karmic, Lucid and Maverick. My initial "very unofficial" packages are (or will very soon be) available in my Ubuntu PPA for download and testing. As part of that process I created a (somewhat minimal) man page for usbsoftrock, so that lintian does not complain about the lack of such a page.

To use my PPA in Karmic, Lucid or Maverick, do:

sudo add-apt-repository ppa:jmarsden/ppa
sudo apt-get update

Then to install this packaged version of usbsoftrock, do:

sudo apt-get install usbsoftrock

and the correct version of the package for your release of Ubuntu (32bit or 64bit, Karmic 9.10, Lucid 10.04, or even Maverick 10.10 if you are running the Alpha version) will be installed for you. If I later update this package, you will automatically be made aware of the update, just as you are for other Ubuntu packages, and you will be able to automatically update it if you wish.

Graphically oriented Ubuntu users who prefer using Synaptic or a similar GUI package manager instead of the shell and apt-get can also add my PPA, and then use their package manager of choice to install usbsoftrock.

Note that this package is untested, because I do not possess any SDR hardware that would allow me to test it! Comments and feedback from those who *do* have such hardware are very welcome. Given sufficient interest, as time allows I will probably package up more SDR-related software for Ubuntu and Debian. Eventually such a set of SDR-related software packages could be added to the official Debian and Ubuntu software repositories, ready for easy installation by end users.

Questions arising:

(Q1) Is usbsoftrock usually used in daemon mode (with the -d option), or in command mode? Since it comes without any init scripts, I am assuming command mode is the usual approach, for now.

(Q2) The COPYING file in the source tarball is GPL-3, but the copyright statements in several of the included source files are "GPL-2 or later". Is there a reason for this? Could it be corrected so the two are consistent? This could help official acceptance into Ubuntu or Debian in future.

(Q3) The two source files interactive.c and interactive.h seem to lack any licence/copyright statement. If these could be added in the same manner as the other files are handled, that could also help official acceptance into Ubuntu or Debian in future.

(Q4) Is there an "official" online place from which the source tarball can be downloaded *without* needing to be a member of this Yahoo Group, and where new releases would appear? This would allow a "watch file" to be created in the package to check for new versions as they are released, etc. There is an automated monitoring system in place for this, but as far as I know it can't work with the files inside a Yahoo group file area, since the monitoring system (obviously) is not a member of all Yahoo groups.

(Q5) Currently my package allows access to the USB device(s) by any user in the 'admin' group. This probably works adequately for Ubuntu, but would probably work rather less well for Debian. Is there any standardization of a "hamradio" or similar group for these kinds of permissions which I should be using?

Lastly, if anyone else is packaging SDR-related software for Ubuntu or Debian, please let me know, so we can collaborate and avoid duplicating our efforts.

Thanks,

Jonathan
AF6YF

Whats on the bench

2010-07-18T19:59:00.009+09:30

Its been a while since I've done an update, so though I'd do that now...

Since I saw 'Three More Words' play a while back at Fowlers, I've been reading up on guitar pedals. I the gig was at a Triple J band competition. There were a few interesting bands. My nephews played a good set, but to my ears at least, I think were let down by the guys on the mix desk. Other bands sounded good and were mixed very differently. Perhaps its as the lads intended, perhaps their pedals?

Any how, there is plenty to read on guitar pedals. A lot more than I expected anyway. There seems to be a religious divide between Hi-Z, unit gain, buffers/amps before pedal and not. Why is this so? I can only put it down to the desire for minimalism/simplicity and/or the old school. The reasons for using Hi-Z buffers and drivers sounds reasonable.

Anyhow, I think I'll do some more work with the audio oscillators and tinker a bit. Thinking about these things as audio 'filters'. I expect it can only help later with debugging AF blocks in radios.

Also on the bench is another lantern prototype. Needs a lot more work, but there is a 28 pin socket, RGB LEDs and associated stuff. Next to add is the ISM band qrpp radios and drop in the ATMEL328 and program it up. =)

Along with an 80 meter receiver project. Using the shottky diodes and ferrite toroids in a component draws that I purchased at a club auction at least a month ago, I built up a doubly balanced mixer. Its now connected to the AF amp and LO on the direct conversion receiver. Now to finish the band pass filter and graft on an antenna input. I found the same circuit in 'Understanding Amateur Radio' from 1977.

So I wonder if this radio was put out as a paper or article by Wes Haywood around 1968? The one that George Dobbs found and built in 1968. In fact I wonder if this is the 'missing' direct conversion receiver that Bill Meara found back in the mid seventies and tried to build as a teenager?

Given I had a birthday recently, I'm inspired to build a radio that is vintage from around the year of my birth. Something designed in the late sixties or early seventies suits and using parts from the early seventies is what I'm aiming for. When I've upgrade my license I'll build a transmitter to match. I suppose it all depends on finding suitable parts, as leaded components are becoming harder and harder to find I might have to find some vintage kit to rebuild my project from. We shall see...

Last weekend I went to a 'zine workshop by the guys from Format. Yes thats how to make 'zines. Pronounced 'zeens'. Little homemade, often short booklets on all sorts of topics. Some examples of zines at the workshop were; mini comics, howtos, short stories, poems, lots of art and collage, just to name a few. I made a 'how to make a Pixie ][' on an A4 page folded to make 8 little pages. Worked out pretty well. Thinking about what other little projects; AF or RF kits, I can fit into that format. Or perhaps it might be better to get 8 A5 pages on two sheets of A4 folded in the middle... more options to explore. I think the first one needs to be about ugly and manhattan construction.

Oh and I picked up a 'little' oscilloscope. Should get in contact David Rowe and return the one I borrowed. Has been a wonderful tool to have. Looking forward to work on gear in the higher part of the HF bands.

Kim VK5FNET

Arduinos in from Little Bird Electronics today

2010-05-31T12:21:00.004+09:30

Last Sunday I ordered a few components from Little Bird Electronics.

A Arduino Duemilanove, several bare Arduino Atmel328, 74HC595, DIP sockets and a bunch of sparkfun stickers. The RTFM stickers are popular ;)

So, some of these bare Arduinos will be used for the lantern prototypes. Some for mcpu for the Nintendo controllers with the ISM band wireless stuff I got last time, one for a controller for a VFO/DDS for my receiver projects and some for temperature logging with a DS18B20. I got one full Duemilanove board to do the initial prototyping on and to program the rest. Should be fun =)

72,

Kim VK5FNET

80 meter DC Rx - Debugging lack of mixing

2010-05-31T12:07:00.005+09:30

Hit the issue with nothing coming out of the mixer. Using the signal injector feeding into the RF input port, I could hear RF static type noises.

So, I spoke to a few folks at the last AHARS meeting. Specifically what drive level from the LO is needed to turn on the 1N4148s. Jim, VK5TR suggests that I will need +7dB. Darryl, VK5JDS suggest about +6dB.

So I made an RF probe, a 10nF capacitor / 1N34 diode / 47M resistor style probe that I attached to the front of the DVM. A simple T shaped arrangement, on a little scrap of copper clad board and put a BNC socket on one end for a CRO probe, the other to a pair of banana plugs to attach to the DVM.

Wonderful; 0.4 volts from the LO. Now to match +7dB up to what volts output that should be...

72,

Kim VK5FNET

80 meter DC Rx - Debugging AF Amp

2010-05-16T12:04:00.005+09:30

This morning I dug out the old signal injector, that I picked up at an auction a while back and proceeded to fumble my way around the AF Amp from the crystal ear piece back towards the input. Signal from the input of the PNP, but not from the input of the NPN. So out with the datasheet, original circuit diagram from G3RJV and my hand drawn copy. I was looking for mistakes in my copy again, when I noticed that the CBE notation on the PNP and NPN. I had correctly copied them down, but wondered if my implementation on the board was correct. The 2N3904 datasheet said no, I had swapped the C for E on the NPN... Fired up the soldering iron, and went off to make a cup of coffee. Ten minutes later I had the signal injector sending a wave through the whole amplifier now. Success at last!

So I reassembled the AF Amp board on the main board and turned it all on. Still no HF static, so I proceeded to poke around with the signal injector, when I put it on the antenna input I could hear some HF static. Well I think it is. It is quite possible that the RF oscillator isn't puting out enough power to turn on the diodes in the ring mixer. Now to make a RF power meter and test the mixer.

You will note in the images, the 'temporary' work bench with tools, the radio shack signal inject has been a good investment and the NPN transistor - 2N3904 - now in the correct orientation.

Kim VK5FNET

How about a DDS tuned from an Arduino?

2010-05-15T19:42:00.006+09:30

I received my Arduino back in 2009 at LCA. I've tinkered with it a bit and really haven't had to many bright ideas about what to use it for. I've been cutting some code recently for the magic lantern project, but the short version is, I need to place another order to get Atmel328s because the Atmel168s ran out of stock.

Anyhow, in the last order I to Little Bird Electronics I got some DS1077 programmable oscillators. They are a tiny little 8 pin SOIC. Been reading up about how to use them now. They have a I2C bus and there is a library for Arduino to bitbang out the commands to send out over I2C. Benlemasurier's DS1077 Library looks like it should do the job nicely. Now to find a carrier board to solder them up to, or perhaps make one...

What will I use them for? Well, a general coverage receiver is the obvious project. I think that that will be a while off yet, but its on the cards.

Kim VK5FNET

80 meter DC Rx step 3 - VFO built and working

2010-05-10T20:39:00.004+09:30

Built up the VFO yesterday, put it on the frequency counter. Seems to even been in the right part of the band. I drew up the circuit on a little note pad, however I miss drew the tuning inductor and the tuning capacitors. So after assembling most of it, I thought that I would double check the original photo and noticed that my selection of capacitors was quite incorrect! The tap also needed extra reading, after I had to calculate the different number of turns from the original T68-2 to us a T50-2 instead. I had to unwind and add a tap six turns from the grounded end, worked it out in the end. Its stable enough once warm, although it was sitting on the washing machine with the back door open with a gentle breeze. I need to find some polystyrene glue or "Q Dope", I believe its called, for gluing the inductor windings. Now to build the filter and find why the AF amp isn't working.

Kim VK5FNET

30 meter dipole down

2010-05-04T09:05:00.001+09:30

high winds in the night snapped the poly cord holding the high end =(
it was old and sun affected.
need to rethink materials.
i've heard about dacron rope.
found none locally yet.

Kim VK5FNET

looking for an interactive perl shell...

2010-05-03T13:41:00.004+09:30

Been playing with Devel::REPL. Its interesting but segfaults a bit. Not sure of thats a problem in my local::lib install, but that much flail is irritating. I like the way most things work, but need to get my head around some strange ness in for loops =)

So tinkering with it to do interactive DBI and DBD::Oracle stuff. sqlplus is fail on a stick without readline support =( I wish that Oracle would move catch up to at least the mid 1990's and add at least basic readline functionality. I wonder if you have to pay extra for that?

I'd like to try Zoidberg, but the current version fails to build. Maybe next version. ;)

Perl 5.12.0 has been released

2010-05-03T13:22:00.004+09:30

Reposting the new release of Perl 5.12. I can't believe that Perl 5.10.0 was release over two years ago, on December 18th, 2007. Has it really been that long?

Perl 5.12.0 has been released!

Release notes follow.

From	Jesse Vincent
to	perl5-porters@perl.org
Date	Mon, 12 Apr 2010 22:28:04 -0400
Subject	Perl 5.12.0 is now available

'Please would you tell me,' said Alice, a little timidly, for she was not quite sure whether it was good manners for her to speak first, 'why your cat grins like that?'

'It's a Cheshire cat,' said the Duchess, 'and that's why. Pig!'

She said the last word with such sudden violence that Alice quite jumped; but she saw in another moment that it was addressed to the baby, and not to her, so she took courage, and went on again:--

'I didn't know that Cheshire cats always grinned; in fact, I didn't know that cats COULD grin.'

'They all can,' said the Duchess; 'and most of 'em do.'

-- Lewis Carroll, /Alice's Adventures in Wonderland/

On behalf of Perl's development team, It gives me great pleasure to announce the release of Perl 5.12.0.

Perl 5.12.0 represents approximately two years of development since version 5.10.0 and contains over 750,000 lines of changes across over 3,000 files from over 200 authors and committers.

SHA-1 signatures for this release:


f533687077e2da113b48a6c5e578f4a206fbf173  perl-5.12.0.tar.bz2
5341e60d099fdda71bc33b2a36e417fc0926518f  perl-5.12.0.tar.gz

You can download this release from your nearest CPAN mirror or from:

http://search.cpan.org/dist/perl-5.12.0/

This release cycle marks a change to a time-based release process. Beginning with version 5.11.0, we make a new development release of Perl available on the 20th of each month. Each spring, we will release a new stable version of Perl. One month later, we will make a minor update to deal with any issues discovered after the initial ".0" release. Future releases in the stable series will follow quarterly. In contrast to releases of Perl, maintenance releases will contain fixes for issues discovered after the .0 release, but will not include new features or behavior.

Notable changes in Perl 5.12 include:

Perl now conforms much more closely to the Unicode standard.
Additionally, this release includes an upgrade to version
5.2 of the standard.

New experimental APIs allow developers to extend Perl with "pluggable" keywords and syntax.

Perl now has a better sense of time and will be able to keep accurate time well past the "Y2038" barrier.

New syntax allows developers to specify package version numbers directly in "package" statements

Perl now warns the user about the use of deprecated features by default.

Perl 5.12.0 features numerous new features, optimizations and bugfixes. You can find a complete list of these changes on the web at:

http://search.cpan.org/~jesse/perl-5.12.0/pod/perl5120delta.pod

As specified in the licenses for Perl (see the files named Artistic or Copying in the Perl distribution), THIS PACKAGE IS PROVIDED WITH ABSOLUTELY NO WARRANTY.

Based on extensive testing over the past 3 months, we believe that Perl 5.12.0 is ready for production deployments. However, you should never blindly trust any software vendor. It is imperative that you test new software before deploying it in production.

While we have worked tirelessly to ensure that Perl 5.12.0 will be a solid platform for your software, it's possible that issues will be found after release day. You can find a current list of known issues with Perl 5.12.0 at http://dev.perl.org/perl5/errata.html

Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.12.0:

Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell, Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrei Yelistratov, Andrew Rodland, Andy Armstrong, Andy Dougherty, Jose Auguste-Etienne, Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh, Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey, Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris Williams,
chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu, Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai, Dave Rolsky, David Cantrell, David Dick, David Golden, David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto, Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz, Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul, Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden, Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros, Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden, Jesse Vincent, Jim Cromie, Jody Belka, John Malmberg, John Peacock, John P. Linderman, John Wright, Joshben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard, Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai, Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz, Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon, Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess, Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer, Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, Tomoyuki Sadahiro, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels, The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen, Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen, Vadim Konovalov, Vincent Pit, Hio Yamashina, Yasuhiro Matsumoto, Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram and Zsban Ambrus.

This list is woefully incomplete as it's automatically generated from version control history. In particular, it doesn't include the names of the (very much appreciated) contributors who reported issues in previous versions of Perl that helped make Perl 5.12.0 better. For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl 5.12.0 distribution.

Best,

Jesse Vincent

30 meter receive dipole up

2010-05-03T07:17:00.005+09:30

On Saturday Karl, VK5FOSS came over and we hacked together a new antenna for 30 meters. Its amazing what a second pair of hands can help achieve, with masts and measuring. The dipole is for 10.140MHz receive for QRSS. Runs approximately North-South, so should have VK2ZAY broadside off the eastern lobe. Maybe VK1AA also.

I no longer have a dipole for 40 meters. To be honest I wasn't using it very much. There just isn't space at the moment. Everything on the work bench/kitchen table is a little bit crowded, aiming to take a week off work soon and get stuck into the painting in the spare room that will become a study for the XYL, then shuffle things around and prepare my study/shack.

Kim VK5FNET

80 meter DC Rx step 2 - AF Amp

2010-05-02T17:43:00.005+09:30

Spent a few hours drawing up and building the AF Amp for George Dobbs, 1968 80 meter receiver.

I now have a small board that I can mount inside a tin intended for the receiver. The tin is a bit smaller than A5 sized and about two inches high. The next couple of days should yield an oscillator. I never cease to be amazed at how the time flies when building...

Now moving on to test it. =)

Kim VK5FNET

80 meter DC Rx step 1 - Diode ring mixer

2010-04-21T22:52:00.008+09:30

Decided to take a break from the QRSS Rx. Its doing _something_ but I don't know if its on frequency or if the bandpass filter is obliterating the incoming RF or if my antenna is really crap.

So I hunted around for another project to keep myself busy with in the mean time. Picked up a copy of Practical Wireless, February 2010. George Dobbs G3RJV, has a receiver first built in 1968 that he re-explores. An 80 meter DC Rx.

Thought it might be a simpler project to work my way through. Also if it pans out, would be good to take it along to the AHARS Show and Tell night.

We just had the AHARS Members Buy and Sell night, a week ago and I purchased a handful of T37's and T50's. This will help move along a bunch of projects I have been wanting to do for ages =)

So here is the first step, the diode ring mixer in the middle of the copper clad board...

I think I will put the band pass filter on one side and the oscillator on the other and shield them both. Then add the audio board on another copper clad board. Perhaps build it up in a Haighs tin...?

Kim VK5FNET

just finished a colpits oscillator for the DC Rx

2010-04-11T22:19:00.004+09:30

Spent a couple of enjoyable hours here on the workbench building up a colpits oscillator, which is very similar to the one recently build by Bill, N2CQR, see over at the SolderSmoke blog.

You can see the frequency counter, 10.13805 MHz. I spent some time mucking around with the variable capacitor in series with the crystal. At best all the options I had would move the rock up or down by 100Hz. Although later when I mounted the variable capacitor in parallel with the impedance matching transformer, I noticed that it would pull it a total of 4Khz. Not sure if this is the right way to tune it, but it seems to work for now. So set it up for 10.140MHz, assembled the LO board into the little case. Hooked the audio and power up to the peecee and fired up QRSS-VD.

So much noise! I turned off everything that I didn't absolutely need and went around rearranging cables. So now the capture is cleaner. However there don't appear to be any QRSS signals in the air ...

Will do more tinkering later and check the clipboard. May need to do a lot more work on the dipole.

Kim VK5FNET

QRSS receiver up and running

2010-04-05T22:20:00.002+09:30

Well its taken a good long while, but I've finished off the QRSS receiver and have a grabber running. I'm not picking up any obvious signals. I have not checked the clipboard, but thought I'd tinker around anyway.

Seems to be something weird going on with the oscillator, I can't get the frequency counter to pick anything up under 66MHz, which is way out of the ball park. I noticed that when I bump the crystal or hold my finger on the crystal the capture changes significantly.

So may need to move the oscillator off the main board and box it up and put a high impedance buffer on it to be able to check the frequency with the external counter.

stage one prototype working

2010-04-02T22:22:00.005+10:30

well the first prototype for the magic lantern has blinken licthen =) am pretty happy with how it turned out. it has six banks of three LEDs spaced evenly around the gap between the external ground rail and the internal power rail...

the arduino will sit in the middle of the inner ring, and all the transistors will be driven from the PWM pins.the leds will draw about 200mA when on full, need to figure out how much current the arduino draws. still need to work out a simple charging method. four AA cells should last several hours. this means that we can charge them from the solar panels directly with a suitable regulator. or we can pull the AA cells out and charge them from a 240v system powered by solar.

so, this is the first part of the magic lantern. todays work was all about displaying patters of light. the second part is interacting with other lanterns. this will require an RF module. however i haven't made up my mind about which module to use yet. it looks like the lobethal lights festival is already using a zigbee for another project, but these puppies start around $40 each. little bird electronics has a $9 module that might work quite well, but we would like to interact with other projects. more on the that later...

Photos here.

more work on the DC Rx

2010-03-15T20:01:00.002+10:30

Spent several hours in the shack over the weekend. Heres the results;

Now need to add power, a 5V rail and the audio out.

I have mail

2010-03-10T19:13:00.003+10:30

This afternoon I came home after work and pfaffed about a bit before realizing that I had not checked the mail. So I did.

I have a couple letters there, after discarding the twenty or so political spam, I found a letter from the ACMA and a hand addressed envelope that was rather battered. Seems to be a local specialty.

So I rushed inside and opened them all up. So I need to renew my license, its about that time. The second was from Terry. Now I was excited!

To my surprise, not one, but three T37 toroids were to be found inside! two -2's and a -6.

So over the next couple of days there will be some winding a happening for the BPF of the DC Rx!

Then perhaps a low pass filter for a Pixie2? Or perhaps I might make another from scratch and lay it up on a new board, smaller than the last. Or perhaps a doubly balanced mixer?

Kudos to Terry, now to get you back =)

More work on QRSS DC Rx and a photo

2010-03-07T17:44:00.006+10:30

Its been a slow week, been home crook most of it. Done a few odd jobs around the house and have been meaning to post this image for a few days. Made a saw horse for working with longer lengths of timber. Getting the paint striping out of the way, so we can repaint the study. Along with lots of reading.

Have added some more components to the QRSS DC Rx. Took this photo before adding the front end capacitors. Spent some time working out a replacement for the T37-6 transformer. Came to the conclusion that I couldn't do it with the materials that I have. Terry has come to the rescue however, he has just received a parcel of various toroids, transistors, etc. Terry has offered to send me one, so I am expecting one in the mail any day now =) This has been along time coming. Really looking forward to getting this rig on the air!

Ooops, just realised that I've not yet put on the feedback resistors... More work to go =)

72,

Kim VK5FNET

Making a band pass filter, or I hate toroids

2010-03-01T18:32:00.009+10:30

I have made some progress on the NE602 direct conversion receiver. I have layed up most the components onto a copper clad board and I now need to add the band pass filter and the front end interface to connect up to an antenna.

I hit a similar problem with the Pixie2 I made previously. I don't have access to any of the named toroids that you find in the HAM radio journals and books. You know, names like T37-6. So I'm doing the numbers to try to lash up a air-space coil instead.

I'm reproducing the 30m QRSS Receiver as built by Hans Summers, G0UPL. Its a hardware defined radio that outouts audio to a peecee to decode.

I have a handful of plastic coil formers that appear to be 1/4" x 1". They have a fiber board on the bottom with five terminals to connect you inductor elements to and your pcb.

So using the calculator at kitsandparts I worked out that following table;

Turns	Inductance
2	0.01uF
5	0.07uF
35	3.67uF

So I've spent half the day crunching the numbers to work out how to get an air-spaced to get the numbers to match the above... The numbers just don't work =/ I'm sure I'll find something and maybe I'll just have to put a bunch of cash aside and make an order to the US.

72,

Kim VK5FNET

First perl module

2010-02-04T11:47:00.003+10:30

Well I've finnaly built up the courage to publish my first perl module. Ideally I can post it on CPAN and hopefully other folks can make use of it =)

While the PAUSE login isn't processed yet, I've put it up on the beginings of my home page. The module is MojoX::Auth::Simple and its a very basic authentication implementation for Mojolicious, with ideas drawn from CGI::Auth. More news as I get there =)

And yes please post any feedback...

First Adelaide Perl Mongers social meeting

2010-01-07T14:59:00.002+10:30

Well, the ball is now rolling. Just has the web site and mail list all sorted and we've put up a date for the first social meeting of the Adelaide Perl Mongers. Alternatively known as AdelaidePM.

We will start ariving around 5:30pm on Friday the 22nd of January at The Exeter on Rundle Street. We will most likely filter out to the back of the "beer garden" to find a coulpe of tables. Perhaps we can head out for food afterwards. See you there.

One 8 step sequencer running on the bench

2009-12-30T10:57:00.004+10:30

I spent a bit too much time googling for synth music and sequencers over the last few days. I had a lot of fun just reading about folks projects and how they built up various kits or designed from scratch different arrangements. I have not really spent much time working with 4000 series or 7400 series ICs in the last ten years. Well not since first year Uni to be honest. That was a long time ago and my memory for truth tables is long forgotten.

So, I almost cheated but finding the friendliest schematic I could find and trying to build that up. You know how it goes, adapting part of this circuit as a stage one of your project. Well I had a few problems. My 4017 wasn't behaving at all! I spent several hours on the bench trying to figure out why I couldn't get the thing to behave. The first problem was that I missed a ground connection on pin 12, eventually running a bypass cap to the reset pin before it settled down and started to do the right thing. But the first LED wasn't behaving itself at all ...

Some further testing revealed that the LED in the first position was a flashing LED! So its now in its own draw, in the component cabinet. The 555 was a whole lot easier to work with and was pretty much doing what it was supposed to from assembly. The potentiometer has a dead spot right at the fast end of oscillator, so may need to swap the wires on the pads, or get a new 1megaohm 'pot'.

I will say that after having the 'friendly' schematic, I did change most the resistor values, add a few extra capacitors and lay it up differently on the plug-in breadboard. Its not a new circuit, but I learned a lot, mainly how to trouble shoot this little thing.

So what have I achieved here? More motivation to tinker in the shed/shack on the plug-in breadboard and play around with the circuit. Getting things working build up the motivation to do more. I have a tall ladder before me. I'm aiming to make the rungs nice a close together. Easier to climb that way ;)

Anyhow, happy homebrewing to all!

72,

Kim - VK5FNET

one dual rail 12V PSU on the bench and working

2009-12-28T16:10:00.006+10:30

Spent a couple of hours researching and then building, testing/destroying, then researching and re-engineering a dual rail power supply for +12 volts & -12 volts.

Not sure what kicked it off, but I am kind of over my 10 meter QRSS receiver not working. I was looking at a ham radio blog, found a video of NE555 and 4017 based synth sequencer. Down the rabbit hole I went reading dozens of web pages, until finally finding the coolest sequencer I've ever seen!

On the Natural Rythm Music site I found a 16 step rotary analog sequencer. It is a visually amazing device, certainly feels more intuitive than you regular 4 blocks of 4 linear sequencer. The builder has a great presentation style and can put together some cool tracks.

This discovery then in turn inspired more and more reading until I found some basic building blocks. Everything seemed to need a dual rail power supply, so I though I should start there. Some web searching, followed by checking a couple of different editions of the ARRL handbook led to a simple dual rail regulated supply. I carefully noted down the schematic, made a parts list and marched off to the shed/shack to build.

Stepping back a ways, I purchased for two dollars, a two amp twelve volt power supply at the radio club meeting. I was a bit disappointed that it didn't work, but put it aside for a rainy days hacking I suppose its the risk you take when you buy gear from a deceased estate, no real history on the item. So yesterday was that day, except it was 32c, no rain and no wind. Makes the shack a little warm.

I amassed all the parts, dissected the old power supply, noted the two 10,000uf 24 volt electrolytic capacitors and carefully discharged then with a long screw driver... the spark was impressive for a power supply that had been unplugged and idle for six months. Note to self, be careful around these caps!

Spent a while working out the arrangement on tag strip, then manhattan style, but didn't find a nice way to mount everthing in the space available. Got a coffee then came back with the lost thoughts of some veroboard of yore...

Found the vero board and worked out a layout on the board from the schematic. Assembled it, checked it twice. Carefully hooked everything up and turned on the power. Everything looked Ok until the LM7812 regulator launched a small part of itself into orbit!

Ok, this wasn't part of the plan! Turned everything off, disconnected everything and started the autopsy. Everything was correct according the schematic. So I checked the schematic against the original. Sure enough the pin out of the LM7812 was wrong and had exchanged the ground and incoming unregulated power line, pins 1 and 2. No wonder it went FIZZ POP!

I downloaded the data sheets, just to be sure. Who would have thought that the LM7812 and the LM7912 would have different pin outs? I mean really?!?!?

Anyhow, I spent about an hour looking for a replacement regulator. Almost despondent that I'd never found one, I happened to find a little plastic draw that had been missing out of the component cabinet. Interestingly I must have put it aside when I first looked at the power supply and thought about reworking it as a regulated unit for 12 volts for my 2 meter radio.

Anyhow, it all went together more easily the second time and it passed the smoke test the second time, keeping the smoke on the inside! Along with providing 11.99 volts and -12.01 volts. The simple test load this time was a pair of 12 volt 20 milli amp four inch fans from a peecee power supply.

So, now to find all the parts for an audio VCO for tone generation, an LFO for effects, mixer for multiple channels, various high and low pass filters and an amplifier... The aim is that all of these will be building blocks for test equipment for RF down the track. Cunning plan huh?

MTB on the road

2009-12-07T21:38:00.004+10:30

I spent some time over the weekend working on the mountain bike I picked up. The complete bike is less than half the weight of my old MTB! Its all aluminium, with the inch wide double walled with eyelets. Currently setup as a single speed, about 70 gear inches. Seems a good balance for pootling around the small hills here. Will fit road tyres at some point in time. Looking at fitting my rack this coming weekend. Then lay up all the gear for a short tour.

VK band plan

2009-12-07T21:27:00.002+10:30

Was doing a bit of reading to confirm the frequency range for 15 meters to think through the IF article in this months AR magazine. So 15 meters covers; 21.000 - 21.450 MHz. I have a hand full of 4MHz and 25MHz crystals.

While I was reading through the band plan, I found something new, and entry for 2200 meters. But what grabbed my attention even more was that there was a mention of QRSS;

137.6 - 137.8 kHz Slow CW modes, e.g. QRSS

bicycle hacking imminent

2009-11-22T14:04:00.002+10:30

grabbed a few bikes from a neighbour that was having a tidy. two BMXs, mainly for the wheels, for the long wheel base(LWB) recumbent that I've been wanting to make for a while. I made a LWB bent over at Lyns place but it has issues and needs a fair bit of work, mainly brakes and gearing. The steering is now sorted.

Also grabbed a alloy MTB that fits well enough and has a disk up front. Put a straight 26" on the back and it feels ok. Need to tweak the chain line, or drop the 1/8" chain for some thing a little more modern.

Been putting more thought into some touring. Still don't have a destination in mind. I think I want to explore the top end of Tassie and some of the northern NSW coast. Those are both big trips, so I think I better start with something smaller, closer to home and flatter =)

So anyone with suggestions of interesting places to cycle tour around Adelaide, Hills and surrounds please let me know.

Adelaide launches a Perl Mongers

2009-11-22T13:52:00.004+10:30

Well my last post about the map and what its missing, is now not missing the entry for Adelaide. Although there still isn't a pin on the map.

Once we have had a few meetings under our belt, Adelaide Perl Mongers will get an official mail list, currently hosted locally. Perhaps even a pin on the Map!

All the kudos to Justin Hawkins for setting up the web site and the mail list =)

So please join the mail list over at Adelaide Perl Mongers, so we can get a meeting rolling for some time early December.

72,

Kim - VK5FNET

Interesting rant on where programming languages should go

2009-11-19T11:25:00.003+10:30

Has some interesting ideas. I suppose it all depends on what kind of programming you do.

Perhaps an alternative would be a tiny thin language that hides the data type to library massaging.
Having to "import os" in python, is an example of why these "modern" languages are stuck in the 70's or 80's etc.

None the less, make me think about the pre-compile vs soft-dynamic languages.

http://www.xent.com/pipermail/fork/Week-of-Mon-20091109/054578.html

There is something missing from this map

2009-11-17T16:07:00.004+10:30

There is something missing from this map.

Can you tell what it is?

No, well we're working on it =)

20091117, quote of the day

2009-11-17T12:07:00.000+10:30

"Is there and app for that? Yeah, on both. Wait, no, it looks like it was rejected from the iPhone store. Droid it is, then."

Foundation License limitations and restrictions

2009-11-17T09:30:00.005+10:30

I have received a number of emails from concerned VK HAMs about the contents of my posts and my 'use' of homebrew transmitters.

It is well known in VK land that Foundation calls are restricted to using only commercial built transmitters with a maximum of 10 watts PEP. However, no other useful or relevant details of the Foundation license seems to be well known.

So let me make two things clear, firstly, I have explored the LCD on all the issues of transmitting and beacons as this is a topic that interests me greatly. Secondly I have not built any homebrew transmission equipment. Only two homebrew receivers and used my Kenwood HF rig and oscilloscope to check that they are not putting out noise on the bands, fundamental or harmonics.

The LCD is particularly vague about the issues around the use of beacons by Foundation license holder. Except that it precludes the use of "computer controller beacons". This does leave plenty of scope for experimentation in analog generation methods. To be honest, in this day and age I believe those most likely to advance this aspect of the hobby are those that grew up in a digital world and have been programming since they were knee high to a grasshopper. However the folks writing the LCD were no doubt born early last century and these new fangled computers will take some time to catch on... I'm not being rude, just a bit disappointed.

That said, I have the basis for a microprocessor-keyer sitting on the shelf, waiting. Waiting for when I upgrade my license.

Which brings me to upgrading from a Foundation license to a Standard or Advanced license. There is a hand book for studying for a Foundation from the WIA, but not the Standard or Advanced. Why is that?

Perhaps this is the reason that there are so many F-Calls out there now? And so many HAMs complaining about there being so many F-Calls. Apparently one more letter is too hard to deal with.

I've tried ordering materials, as advertised on the internet, but unresponsive is the nice way to summarise. Its too hard to get the materials to study to upgrade, unless you are lucky to be part of a club with materials. If you're not part of one of those few clubs, I've noticed they don't share. Why is that? There doesn't seem to be much collaboration in that space. Or I'm just not in a position to see it, because I'm only an F-Call. Its a bit of a catch-22 if you ask me. I;m sure they work hard to produce the material in the first place, but you will get more recognition and more amateurs if that material is shared around the clubs. Free or at cost or more, it doesn't matter. Get those materials out there!

I've been flamed on mail lists for asking about topics that only Advanced calls are allowed to use. So my response was how am I supposed to get my Advanced license if I don't know about these topics, their response is, you don't until you are a Advanced call. There is definitely a weird head space around learning for your upgrade. You are supposed to learn it all yourself and asking for help is cheating.

That said I want to upgrade to Advanced and to tinker with QRSS and build my own kit.
Its just a shame that there is so much attitude around being a F-Call with aspirations.
There are some local HAMs that are very helpful. They have been inspiring, but their time is quite limited. Which is why I try to make the most of my time at club meetings. There are other clubs north and south that would be beneficial, but getting to and from the meetings is a serious hassle. Perhaps I just need to get a car or motorbike of my own as public transport isn't an option, thanks to Adelaide's central hub transport model.

I know that AR wants articles on what F-Call are up to and think, but I doubt they want to hear about the plight of what F-Calls can't do. "Become a WIA member!" and "Upgrade! Upgrade!" I hear folks say...

Anyhow, I've dropped a lot of other interests and other clubs' activities so I can focus on work and amateur radio. Hopeful over the Christmas break I can finish my upgrade study and sit the exams...

building an oscillator

2009-11-16T08:52:00.005+10:30

I'm built an oscillator, for 28.188MHz based on the Genesis Q5 from VK1AA. Well, I had smoke. I'm still working on the plug-in-bread-board. I think the lesson is not to use 12 volt gell cells for testing out new ideas. Can supply far too much current too quickly. Now I understand the little 9 volt battery role in life...

The little 74hc04 squealed then popped! Took only a second. I'd put the 7805 in the reverse position. Its a 50-50 chance ... Lesson there is to not turn the pluging board around all the time and loose track of the orientation of things, I think.

So with the regulator in the right way now, it gets pretty warm, so I've added a heat sink, but not tested it again. Will have another go when the 2 meter AHARS net is on this evening, in the shed.

At the end of this, I might order a G5 or two. I expect that I'll need a few for various prototypes anyway. Just want to get a couple of modular oscillators up and running for receivers =)

72's

Kim - VK5FNET

new 10m dipole

2009-11-15T10:19:00.006+10:30

Replaced the dipole this morning. Cut to length some pvc coated speaker cable that had once been an end fed long wire. Its light and grey so not so easy to see as the red 30amp power cable I was using before. Also ran coax straight up to the center of the dipole and will run a similar arangement to the QRSS Rx of Hans Summers, G0UPL. Now onto modifying the receiver =).

72's

Kim - VK5FNET

Saturday works

2009-11-14T23:13:00.004+10:30

It was pretty hot today, was forecast to be 39c. Didn't feel like it, but did slow me down running about the place getting the antenna up. None the less I have a dipole for 28.188MHz up. Its currently mounted as the third guy rope of the mast that I ran the old WiFi gear on. The router board that was running the WiFi stopped for no particular reason, so I'm suspecting the power supply section of the board, needs further investigation. I removed all the WiFi gear from the mast and reset two of the stainless steel guy ropes. Made the 10 meter antenna the third guy...

It works, probably not nearly as well as I'd like, perhaps I should build a Z-Match tuner for it instead. So, I setup the little Kenwood and tuned all around 10m. There was some fast CW but little else was heard on the band.

So, the 'ladder line' is a nasty hack. I grabbed a couple of plastic tent pegs and some cable ties. Its not so good, needs frequent adjusting. There was plenty of activity on 40 meters. This little dipole is about six meters off the ground, double the height of the previous dipole for 40m.

Actually it is the 40m dipole with the rest as the ladder line. And lots of string and a couple of eletric fence insulators. The old balun is currently in, but I'm not sure that the 4:1 is appropriate. Is a 1:1 better suited to a ladder line? Sorted out some coax and connectors too.

Dug through some boxes that I picked up at the last AHARS meet, grabbed some bits for to setup the audio into the peecee. Also found a 0C70 and a 0C71 ... I think they are germanium audio transistors.

72's

Kim - VK5FNET

QRSS receiver crystal for 10 meters

2009-11-12T21:10:00.014+10:30

The 28.188MHz crystal arrived today from Nick, VK1AA. Have been hanging out for it to arrive and would really like to get a receiver up and running.

This weekend looks like being a scorcher, about 38c, so a bit of indoors building will be in order. Which also leads one to think about oscillator stability. With night time temperatures of 15c to day time temperatures of 35+c degrees there is plent of room for drift.

Thoughts on work to do;

An antenna for 10 meters; vertical or dipole?

If heading down the di-pole route, balanced or OCFD?

Maybe a balun?

A transmission line should be straight forward, I have some spare clean RG-213.

How about a tuner, then how do I measure if its really working?

If a vertical, what about a copper cactus or a just a 5/8 vertical?

Should I make the local oscillator in a separate box?

If so I could drive the Kenwood to TX test ... wonder what specs are required to drive its VFO port?

Then modify the 'sudden tunner' style DC receiver. Based on an NE602 and LM386.

Hook up to peecee with 96KHz sound card.

Grab with glfer or baudline.

Announce its ready...

Later develop something more focused around web based delivery.

Find a design for a non-computer 'controlled beacon'. A condition of the Foundation Licence.

Perhaps a beacon controller as simple as a pair of NE555's and a 4017. The first NE555 at a 30 second on/30 second off interval, driving the clock line of the 4017. The first output pin of the 4017 could then drive the second NE555 with a 3 second on/3second off interval. Effectively sending a '5' every ten minutes in QRSS 3 second dots. The '5' being from the call sign of VK5. My call sign being VK5FNET. But thats a job for another time, but would be nice to know what folks think...

So, thoughts on work to be this weekend;

Get any antenna up

Get a length of RG-213 terminated with PL259 connectors

Blow the dust of my 4:1 balun I made some time back and check the connectors out

Modify the 80m DC RX to run on 10m

Patch up some audio cable for the DCRx to peecee sound card

Work out how to capture images or do screen dumps from glfer

Announce it...

Doesn't sound like much on 'paper', but on top of the domestic chores should be a busy weekend.

72's

Kim - VK5FNET

10 meters

2009-11-10T21:43:00.005+10:30

On the Knights QRSS mail list theres been talk of activating more HF bands. Specifically 10 and 15 meters. There issues with activating 40 meters as there are access issues for non advance licences in the US and band plan issues across Europe. Not 100% sure how 40 meters is carved up elsewhere, but in Australia, Foundation, Standard and Advance all have access from 7.000-7.300MHz.

There have been a couple of contests on 10 meters with some success. This has lead to conversations on list to start putting SDR receivers and QRSS transmitters on 10 meters. The 100Hz QRSS band is 28.188,000 - 28.188,100 MHz. Folks have used other portions of the 10 meter band, around 28.322MHz if I remember rightly. Which seems to be around the QRP and QRO un-manned beacons.

Nick, VK1AA who is shipping the G80, G40, G2030, and G5 Genesis radios, has put up an offer to send out a batch of crystals on 28.188 MHz to folks free. So long as they get a MEPT or receiver up on the air for QRSS. I shot off an email straight away and am still patiently waiting for it in the mail.

I have started mods to the W1AW NE602/LM386 direct conversion receiver I build up for 80 meters. Needs rework on the band pass filter and local oscillator. Should be fun!

72's

Kim

Wordpress-MU deployment at work

2009-10-07T15:32:00.002+10:30

I'm rather happy that this project is finally coming to an end. I've moved jobs within the University of Adelaide, but I'm still working on our blog servers. It's funny how projects follow you around. Before the underlying infrastructure, now the actual blogs.

So it has an actual blog on it and we've put up a bunch of video from the Open Day we had a month back. The AV guys did a great job. So in time we'll move across other news sites from the main web site to the blog. While I've been hacking away in perl for the last few months and really enjoying that, Wordpress-MU or WPMU is in PHP. I haven't really done any serious work in PHP since I've been back in Australia, but its not hard to get updates in there =)

Kudos goes to Phil for content and plugins, and Scott for themes. Also the Open Day crew for great work organising all the speakers and video.

use Getopt::Long;

2009-09-22T11:38:00.003+09:30

This mornings very short moment of enlightenment was related to the use of Getopt::Long.

I had been messing with passing command line arguments to my server deployment script and had completely failed to get the --verbose flag to work the way I expected.

So I read the perldoc on it and found that I had been going about this the wrong way altogether.

I had this;

my $VERBOSE = 0;
GetOptions( "config=s" => \$config_file,
"verbose=i" => \$VERBOSE,
"modules" => \$INSTALL_MODULES );

print "DEBUG: message" if $VERBOSE;

Then on the command line I had to specify --verbose 1 or --verbose=1, which really wasn't what I had in mind. So this morning the mist on the man page cleared and it all clicked.

If you use "verbose!" => \$VERBOSE, then you can use --noverbose to unset the flag if you have previously set it in your code above. I'm not sure why I moved to using "verbose=i" => \$VERBOSE, but "verbose" => \$VERBOSE was not working as expected.

Anyhow, I was talking to Andy about putting "!" character after the command line flag name and now --verbose sets the variable $VERBOSE and it behaves as I previously expected.

HF Lunchbox 1 lives again

2009-09-15T13:56:00.007+09:30

This morning I dropped in to see Barry VK5ZBQ. We had talked about catching up to sort out one of the two Codan 6924 HF radios that I purchased at an AHARS members meeting auction.

So this morning was "the day". I had a minor ordeal to get there, including losing my bus ticket, missing the bus, then catching a lift after the car would not start. I arrived about 9am and was undoing the case screws to get down to business shortly afterwards.

Barry has a manual for the Codan 6924 Mark 1, so we looked up various sections that I was curious about. Barry set the rig up on the test bench, powered it up, connected it to the signal generator, selected the frequency for channel 1 and we heard the dual tone from the speaker on the front panel. Win number 1. Then we set about transmitting from the rig. The power meter on the signal generator shows out going power when hitting the antenna test position on the mode selector. So out with the multimeter, leading to the detection of a broken microphone lead.

The chassis can be separated by removing some screws and nuts, so you need tiny fingers or a little tool to hold the nut so you don't loose it. So Barry opted to replace the microphone lead with something a little more robust than the original lintz wire type. Apparently you can't solder it very well. So the new lead went in. Took a little while as its quite a fiddley job. We reassembled the chassis and microphone and connected up the output to the oscilliscope. Fired up the HF rig, tuned to channel 1 and tested it. Win 2. We have a nice upper side band trace on the scope and after a bit of fiddling with the HF radio antenna and dummy loads, we hear the transmitted voice from the HF rig.

At this point I'm very happy, as the radio works properly and we work out that it puts out 8-11 watts PEP. The antenna tuner varies the output power a lot. Need to sit down with it and work out how exactly the tuner works, it has a loverly wound toroid with wiper for continuously variable inductor. Now I'm ready to attack the idea of a VCO in stead of a fixed crystal oscillator.

We break for a cup of tea and Barry explains to me how the upper side band (USB) and lower side band (LSB) filters work in the 6924 and what I'll need if I change the oscillator to a 80 or 40 meter band. Apparently there were kits for this, but I've found no documentation. So I will draw everything up and go back to Barry and run it by him. I think I'll work out what crystals I need and populate the remaining empty crystal oscillator board first to get the hang of it first =)

Now that the weather is warming up, I can spend more time in the radio shed/shack. I've put together a dipole for 40 meters along with a 4:1 balun and suitable cable. Should be fun.

Kim VK5FNET

Thoughts on servers and network services

2009-09-06T12:12:00.002+09:30

This is a post that I sent to the Melbourne Wireless mail list. Thought it might be useful for others so I am reproducing it here;

Hi Victor,

Victor wrote:
> > Thanks everyone for the replies so far. At this stage will be sticking with a Intel Atom 330.

I run a dual core atom here, low on power, not particularly fast,but thats the balance you are after if you are going atom I suppose. Always spend as much as you can on RAM! 2GB+

> > When it comes to an OS for the server, I know a little bit (read NOT a
> > lot) about linux, enough to get me through things... Should I look at
> > setting up CentOS on this or is that possibly a bit too "much" for a
> > relative "youngin" into the world of Linux per se.

The only way to learn is to do. Don't let various folks opinions put you off =) There is plenty to learn and lots of different paths to take ;) If you're new to Linux/UNIX then maybe you can head along to your local LUG, Linux User Group. I'm assuming that you are in/around Melbourne so have alook at; http://www.linux.org.au/foss_in_australia/LUGS/VIC

> > I read somewhere that CentOS isn't for the light-hearted?

Centos is geared to be a server OS. It has a few quirks and its configuration like RHEL, is a little different to other Linux distros. I have used RedHat RHEL3,4&5 a lot and Centos mirrors them in functionality, etc My only complaints revolve around; packages in the Perl and web areas are well behind the times and they still use RPM with broken meta package dependencies! If you stick to the default repositories you'll be fine, but the packages are limited. Have a look at EPEL if you need more packages/software...

Generally speaking RHEL is solid enough and stable enough to do most server tasks well. So if Centos lives up to its name of being RHEL with out the irritating license bits then its all good experience on the Resume too...

> > Other possible options is FreeBSD, Debian 4 or Ubuntu 8.x

I have run all the above at work and at home for various uses.

If you really don't have much UNIX/Linux experience then perhaps Ubuntu will give you the least troubles installing and getting around.

Ubuntu is primarily focused at the desktop. The server version has a number of buggy things that are tied to the design decisions around init/startup script and network interface management. Fine desktop. I would recommend it to anyone starting out in Linux. Then you can grow from there...

I run a number of Debian server at home. Solid, stable, but some packages are old. This may not matter in the beginning. Networking is rock solid, more packages that you can poke a stick at. Seriously lots.

FreeBSD I have not been keeping up to date with over the last four years... There was a lot of development in the desktop arena that wasn't interesting, as I primarily used it for servers. Its solid, networking was solid and fast. It was death by compile your own packages. Hopefully this has changed. They have been moving fast, hopefully the ports tree is uptodate. Was the main reason I dropped FreeBSD. Still have NetBSD boxes here for old school non-intel hardware, Alpha, Sun, VAX, etc.

Also, not on your list, but worth a mention is OpenSolaris. I installed it on my laptop. Was pretty happy with it, except no support for my WiFi.

Another thought, to get you going; virtualise! I know it was mentioned else where in this mail thread, though I'd add to it.

I have recommended to folks in our local LUG, put Ubuntu on your machine, install VirtualBox and install the other OSes in virtual machines. More doco; https://help.ubuntu.com/community/VirtualBox

Yes VirtualBox is targeted at Desktop installs with the guest OS in a window, but it gives you a feel for the guest OS with out much investment into building another real machine. You can shut it down and boot it up, tinker with it later. Some videos; http://video.google.com.au/videosearch?q=ubuntu+virtualbox

If you get real serious about virtualisation, perhaps the simplest remote managed VM server is the Oracle Xen based stack. I saw a demo of it at LCA2009 in Hobart. I was quite impressed. Managed through a web browser. Not through some heavily licensed Windows sever like VMWare =P You can play with all the iSCSI stuff and file system mirroring etc, lotsa fun =) Doco on Oravle VM; http://wiki.oracle.com/page/Oracle+VM

VMs are only good if you *really* need separation of different server apps from each other, IMHO. There is a lot of overhead in running VMs, on machines that don't have the virtualisation instructions. I don't run VMs on servers at home any more. The only reason I would is if I have to tinker with different OSes for debugging. Another reason would be snapshot file system backups. I do have a few VMs on my laptop to demo, test code, or compile code...

I'd recommend figuring out what "network services" you want to run and run them on their own interface on the server. Have a look at the 'ip' command. You can run more than on IP address on each physical ethernet interface (NIC). Then you can make the application/service listen on that IP and then tighten up your firewall rules with 'iptables'.

Doco on iptables etc; https://help.ubuntu.com/community/IptablesHowTo
More info here; http://netfilter.org/documentation/

Then once you've played with all that, theres the amazing arena of routing =)

Old school protocols;
- OSPF; http://en.wikipedia.org/wiki/Open_Shortest_Path_First
- BGP; http://en.wikipedia.org/wiki/BGP

New protocols;
- OLSR; http://en.wikipedia.org/wiki/Optimized_Link_State_Routing_Protocol
- B.A.T.M.A.N.; http://en.wikipedia.org/wiki/B.A.T.M.A.N.

Download;
- quagga OSPF&BGP routing software; http://www.quagga.net/
- olsrd routing software; http://www.olsr.org/
- batman routing software; http://www.open-mesh.org/

Talks;
Thought this talk might be interesting; David Rowe presented at Linux.Conf.AU in Hobart this year on the MeshPotato about the village telco model, using B.A.T.M.A.N. as the routing protocol;
talk notes; http://lca2009.linux.org.au/programme/schedule/view_talk/46?day=all
talk slides; http://lca2009.linux.org.au/slides/46.odp
talk video; http://mirror.linux.org.au/linux.conf.au/2009/Friday/46.ogg

Anyhow, have fun with it =)

regards,

Kim
-- http://vk5fnet.blogspot.com/
_______________________________________________
Melbwireless mailing list
Melbwireless@wireless.org.au
http://wireless.org.au/mailman/listinfo/melbwireless

Repairs and receiver experimentation

2009-06-22T22:01:00.005+09:30

Its been a while since there was some progress on the workbench. This last weekend kicked off by reassembling the frequency counter after re-soldering every joint on the board. It took about two hours to do, but it has all paid off, its now working comparing against a known working source.

I started tweaking the direct conversion receiver, with less success, but got to test out a number of other crystals along the way. 2MHz oscillates stably at 1.999999MHz, while the 25MHz crystal does not. I changed a number of different inductors and NPO capacitors to similar values to other circuits I've seen, but to no avail for 25MHz... So much for the idea of 25MHz +/- 3-4MHz VFO. There are plenty more options to come though. Found what looks like a pair of FT37-43's. Will have to check the datasheet but they look about the right size and came from a mystery box from a junk sale a while back. Will tinker with it some more.

The DC receiver picks up a lot of terrible noise around 1.8MHz which I assume is AM broadcast with the 2MHz crystal. Need to tinker more with that, and see if I can find a better way to link up the front end, not using a band pass filter to give me more tuning range. Not really sure how this works yet, but theres a lot of draw design found from the net and build. Probably hitting impedance mismatch issues. I'm sure I'll figure it out eventually.

I think its time to migrate the DC receiver from the breadboar to a manhattan board. I'm finding that the more I tinker with it the less it works. Probably connections of the components being dragged around by CRO probes, etc... Well its too colder to hang around in the radio shack any longer.

mashup ideas: solar powered radio

2009-06-08T11:50:00.005+09:30

From the maker blog a while back they ran a series of posts on joule theif.

Bill on the SolderSmoke blog ran a couple of articles on mechanically keyed transmitters, like the ET phone home rig, also a rew ideas around clock powered keying.

So my brain was buzzing away recently and it wasn't until I spotted the solar powered garden lights, that ceased to work a couple of months ago, that I thought about re-using them. The little solar cells only put out 0.8-1.1 volts. Three in series put out around 3.2 volts in full sun light. I need to go back and see what kind of current they can sink though...

To power something like an arduino keyed tx or a DC receiver with NE612, I would need a solid and regulated 5 volts.

It wasn't until this morning, on the irc channel of our local homebrewers, that I thought about mashing up the joule theif and the 80 meter DC receiver to make a solar powered radio =) It would make it limited to day light hours, but its certainly workable. Still have some other things to work on first, but certainly the next project on the list =)

2 Meter Portable Ops

2009-05-24T03:03:00.000+09:30

Yesterday Karl VK5FOSS and I VK5FNET, worked through the check list to do a test set up for the 2 meter portable rig. The aim was to get all the kit together for operating in the field. Why would we do that you ask? Well last year I wasn't really quite ready for either of the rallies that we worked at. The ROSA and the Classic Rally of Adelaide. Both time Karl and I worked as radio operators. The main function of the role is to record information on the stage and pass this information as 'messages' to Rally Control.

HAM radio operators work under the banner of WICEN. WICEN is an organisation for emergency radio communications to help in message passing for the emergency organisations like the Country Fire Services, Police, Ambulances, etc. The aim here is for radio operators to work well under pressure to get messages through under tricky conditions. I've been told that despite the technical problems I had at the rallies, I did a good job and should continue working in this field. So once I am confident I have useful portable kit I will join WICEN and do more formal activities with them. Here is a summary from the de-brief of the last rallies.

Anyway, so yesterday we made a list of things we are missing and working to narrow that down. Along with places to find said missing items. Things like; good rope, large non-black tent pegs, tubing for another mast, extra RF patch cables, another dummy load, a good box on wheels that can be pulled or pushed like a sack truck and fix my SWR meter.

So later in the day we put together a couple more patch leads and a 7.5watt dummy load for Karl. I have also spent a fair bit of time working on the SWR meter. I looks good to me, but I think I'll follow up with some of the local HAMs to confirm that its accurate as I had to repair the input connector. Which meant disassembling the whole thing and rebuilding it again, which means it will need re-calibration.

Was planning some more study for the next exam today, but a long list of around the house jobs are yet to be done. You know the ones, mowing, digging, weeding, tidying... Maybe tonight =)
The main reason I need to push to get these exams out of the way is that I really want to work packet at the next rally. This is where my radio/linux/networking/computing interests all meet. There is so much stuff to explore in this space, thankfully it doesn't seem to change very fast, so I will have a chance to catch up =) Then I can start work into the areas of HF and 2 meter packet radio with some of the local guys. Not sure where that will end yet =)

Kim VK5FNET

Progress on NE602 based direct conversion receiver

2009-05-24T03:02:00.000+09:30

So today I stayed home due to brain pain, it had been building up for the last few days. Also I had difficulty with my balance. To the point that walking involved bumping into everything. Lots of water and pain killers helped a little, breakfast and coffee later helped a little too. However the head ache didn't wear off until late into the afternoon with more sleep. So I spent some of the day sitting down, tidying the shed.

The cool thing about that was I found a couple of little paper bags with parts that I had bought months back and promptly filed for safe keeping in boxes! Anyhow, that list of parts contained an SA602, 3.579MHz crystals, a variable poly-cap, a large breadboard and some zeners.

This was all the missing parts for the NE602 based direct conversion receiver I've been wanting to build. So late this afternoon I sorted out all the other parts, put them in a box and setup on the kitchen table to assemble. My soldering iron and other tools are currently at a friends, so I pretty much had to assemble everything up on the breadboard.

Made dinner, a tasty curry with shallot pancakes. Then assembled it as per the circuit from W1AW. I am not sure where I first found it, google has a few references to it about. There are also a few variations on the NE602 direct conversion receiver, like the MRX-40_Mini_Receiver and another that I like using LC tank circuits for both the RF input filter and the oscillator side.

I fired it up but heard absolutely nothing. Much comparing with the diagram led to adding the vcc and ground rail for the LM386, after which I could hear familiar hash with the speaker held very close to my ear. I dug out the Pixie2 hoping to create some kind of signal. However the oscillator from the Pixie2 did not create the expected signal or inteference on the DC receiver. So this needs looking at another day when I can focus for more than ten minutes at a time. Hopefully this coming weekend wont involve any more headaches.

Kim VK5FNET

Fun with radio - part 2

2009-05-24T02:53:00.001+09:30

Now that I have built a receiver, as the first stage in a QRSS grabber, how do I calibrate it?

I commented in Bills blog, SolderSmoke News, about the how the two pixie 2's David Rowe and I built were not on the same frequency despite being the same circuit. They are about 2KHz apart, which we put down to the tolerances in the components.

My HF rig has a 'digial readout' that measures down to 1KHz increments. QRSS uses a 'band' of 100Hz wide. Thats right, a tenth of what my smallest increment on the HF rig. So how to I measure that?

I'm looking to build a frequency counter or meter. Are there homebrew designs out there?

kim vk5fnet

Fun with radio - part 1

2009-05-24T02:51:00.001+09:30

Yesterday I spent an afternoon working with David Rowe building a Pixie 2; www.kenneke.com/~jon/pixie/

The Pixie 2 a tiny direct conversion radio intended for training new HAMs in under standing radio and building electronics. The initial build was a little bit troublesome as the oscillator wasn't. This makes it quite hard to build the rest of the radio, as it can be built in stages; the oscillator, the PA/detector, the audio amplifier.

Well the afternoon turned out to be quite productive and with a working radio picking up Davids Pixie transmitting from a foot away on the work bench. It puts out a whopping 200milliWatts and the output waveform on the oscilloscope was very sinusoidal.

David has a full amateur radio license and is a very cluey electronics engineer. I have my foundation license, so while I'm not worried about building a transmitter yet, I am quite interested in software defined radio(SDR) and QRSS. Which is what this project/journey is all about.

Whats next? Well as I now have a DC radio with audio output, SDR being the end goal, the next thing to build is the audio interface to the laptop so I can get the Linux QRSS client running...

kim vk5fnet

Band Pass Filters

2009-05-24T02:50:00.003+09:30

Last night I built up an input band pass filter. The point of this little beastie is filter out the RF from above and below the band or radio frequency that you want to receive on.

I found a page on the band pass filters.

So the original Pixie 2 circuit - a direct conversion receiver I'd like to use for QRSS - has a low pass filter. Firstly, the reason the BPF project was started, is to remove all the spurious noise from other bands. Mainly the huge signal from the commercial AM broadcasters around 1.8MHz. Secondly, I want to make pretty sure that I'm not spraying harmonics across higher bands.

Some testing with the original LPF from the crystal oscillator shows a nice sine wave like signal with some noise on the peak of the upper cycle. However the Chebyshev BFP has lots of harmonics and looks like its attenuating a lot. I need to get some advice on reading the output of my CRO. Also a spectrum analyzer would be a very hand tool. But I'm not real happy with the output of the Chebyshev, it actually looks worse than the input side from the oscillator.

It seems, on advice from VK5TR / VK5JST, that many of the generic toroids from Altronics, DSE & Jaycar, may not have a suitable Q factor. Jim suggested the FT68-41 toroid cores. The suggested core is the T94-6. Will have to find a source of toroids specifically for the purpose. Not found any local suppliers, but will keep looking.

BPF == band pass filter
LPF == low pass filter
HPF == high pass filter
CRO == cathode ray oscilloscope
harmonics == multiples of the frequency that you are generating

Kim VK5FNET

More on toroids

2009-05-24T02:50:00.001+09:30

Been searching for info about the toroids from Altronics. Setting up a band pass filter for the QRSS receiver.

The L4534 seems to be the same dimensions as the T130-2.

OD = 1.30 / 33.0 mm +/- 0.02 in
ID = .780 in / 19.8 mm +/- 0.02 in
Ht = .437 in / 11.1 mm +/- 0.025 in

Also I've found a useful site on the standard sizes.

The T130-2 has a AL of 11 +/-5%. So then to calculate the inductance like so; uH=(AL*Turns2)/1000

The L4517 does not match up to any of the standard sizes. Its just a bit bigger than the T50-2. So I'll use that as a model and obviously subtract some turns ...

I have three of the L4517's would with 36 turns of 0.5mm enabled wire for an inductance of 12uH. Now to pick out the capacitors for the BPF. Then find the smallest way to build it all up on copper clad board for the Pixie2 in the Haighs tin.

kim vk5fnet

Fun with toroids

2009-05-24T02:49:00.000+09:30

The aim here is to find an inexpensive source of toroids for kits for QRSS receivers. Jaycar and Altronics have a reasonable number of shops around the place and also do Internet and mail order, so folks should be able to get the parts easily enough.

Anyhow, some time back I picked up all the 15.2X8.53X5.94 toroid cores, L4517 the local Aztronics. They sell from the Altronics catalog. So these cores are not standard sizes or models that are used in HAM radio, so far that I can make out. They are pretty close to a T50-2, as they are supposed to be iron core, but are a bit larger diameter. Using 0.5mm/24bs enameled copper wire, WW4016, from Jaycar, I've spread the turns out over at least 80% of the toroid, values as follows;

10 turns gives 0.001mH

20 turns gives 0.003mH

25 turns gives 0.005mH

36 turns gives 0.012mH - for 3.5MHz BPF

I could probably squeeze on another 5 turns, but 10-36 turns covers the inductance that I need right now. Perhaps other gauges of wire will yield other usable values. These toroids as they are setup are intended for low pass filters or band pass filters. The Pixie 2 needs just one in its current configuration. I intend to build up a better filter as there is lots of AM broadcast signal there when down on the flat in Adelaide.

kim vk5fnet

dreams of arduinos

2009-05-24T02:48:00.001+09:30

Its one of those local public holidays today. Cup day or something. The kind that make you sleep in, warm enough to organise firewood and mow the back lawn. Well whats left of the lawn from the water bans and hot summer, but then theres the go inside time. Cool down with a chilled beverage and surf the 'net time.

I've been following the SolderSmoke blog and podcast, Bill mentioned that he put in a submission to Hack A Day about QRSS. Hack A Day is one of those sites that just gets the juices in the brain a pumping and thinking about building various things.

The first thing I found this morning was pluggable modules on an arduino shield, like lego blocks to enable fast prototyping of hardware and software.

The second was a two servo, four legged robot powered by four AA batteries and an Arduino.

The third was a tiny parallel supercomputer; the non-von1-supercomputer. There was another project a while back implementing a basic stamp supercomputer.

From a link somewhere I found one of the things that I keep crossing paths with, a home made Arduino board project. I found one today that set my mind racing off down the path of pluggable modules; the cheapduino.

So while not specifically parallel, but pluggable architectures of embedded systems. It could simplify the design of the individual board if a backplane had all the power, clock and a MPI interface for each CPU.

Perhaps a single USB connected backplane with a serial interface for each pluggable daughter board, in a simple frame that lets each daughter board have an edge connected I/O space. Something like the cards in a QBUS VAX. Smaller obviously, about five centimeters or two inches a side.

On that you could build a service per CPU, say, temperature logging, writing to a SD card, inrfa red comms., two wheeled robot platform built with servos, xigbee Tx/Rx, bluetooth...

I'm sure that there are loads of other ideas in this space. Its all about context and filling a need, its just strange some days where ones mind wanders... parallel pluggable embedded systems, which I'm sure one call call a mini-frame. Hmmmm ... theres an LCA talk in that I'm sure.

Kim VK5FNET

Podcasts I've been listening to recently

2009-05-23T16:35:00.001+09:30

Recently I've been listening to a couple of podcasts about HAM radio, homebrew, computers and Linux.

I have been hanging out for the next podcast from Bill N2CQR. Bill posts usually once a fortnight and keeps an interesting blog called SolderSmoke. Homebrew amateur radio, some travel log, some amateur astronomy and other related geeky things.

A couple of weeks back I found Linux in the HAM Shack, which is self explanatory really. Russ K5TUX and Richard KB5JBV, aim to walk you through all the popular things you's likely do with computers in HAM radio. Assume radio experience, but not Linux experience.

I have at least a hour bus trip to work and then another hour home again, so these podcasts help fill the voids in my head with useful radio thoughts =)

Kim VK5FNET

SolderSmoke the book has arrived

2009-05-22T15:21:00.000+09:30

My copy of the SolderSmoke book has arrived. Much reading ahead.