Monday, December 27, 2010

New key

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.

Monday, November 29, 2010

OSDC trip

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

Wednesday, November 17, 2010

Monthly update, November

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

Tuesday, October 26, 2010

Wireless Networking in the Developing World book

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

Sunday, October 24, 2010

National Field Day 2010

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

Sunday, October 17, 2010

Copper cactus J-Pole - part 1

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

Wednesday, October 13, 2010

SolderSmoke 126.mp3 is out

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

Tuesday, October 12, 2010

Friday, October 08, 2010

Web Cams for Linux

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

Sunday, October 03, 2010

Interesting power generation projects from the crew of HackerSpace Adelaide

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;, 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

From the WIA broadcast news this morning;



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;

The VK5 News: 3rd October

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

9,10th foundation license
23rd October, Nat Field Day
20th, 21st November foundation license training
QRP CW @ Rostrevour Tennis Club
More at;
VK5PH Paul

Friday 15th October; Meeting at the Reedbeds; Talk on coax cable, types, suitability, tools included
More at;

Tuesday, September 21, 2010

Back to studying

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 SolderSmoke 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.



Monday, September 20, 2010

Word of the day: flum

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 =)



Thursday, September 16, 2010

Exciting things at work

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

Friday, September 10, 2010

junk code

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.

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";

72, Kim

Tuesday, August 31, 2010

How small can you make antennae?

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

Tuesday, August 10, 2010

Quote of the day by SKR

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;

AHARS Symposium September 19

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

Saturday, August 07, 2010

Voltage dividers for 5volt Arduino and 3.3volt SPI devices

I am setting up a radio module to plug into an Arduino.
Specifically the RFM12B like in this schematic;

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

Thursday, August 05, 2010

usbsoftrock Ubuntu package, from the softrock40 group

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.



Sunday, July 18, 2010

Whats on the bench

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.


Monday, May 31, 2010

Arduinos in from Little Bird Electronics today

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 =)



80 meter DC Rx - Debugging lack of mixing

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...



Sunday, May 16, 2010

80 meter DC Rx - Debugging AF Amp

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.


Saturday, May 15, 2010

How about a DDS tuned from an Arduino?

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.


Monday, May 10, 2010

80 meter DC Rx step 3 - VFO built and working

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.


Tuesday, May 04, 2010

30 meter dipole down

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.


Monday, May 03, 2010

looking for an interactive perl shell...

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

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.

FromJesse Vincent
DateMon, 12 Apr 2010 22:28:04 -0400
SubjectPerl 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:

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:

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

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.


Jesse Vincent

30 meter receive dipole up

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.


Sunday, May 02, 2010

80 meter DC Rx step 2 - AF Amp

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. =)


Wednesday, April 21, 2010

80 meter DC Rx step 1 - Diode ring mixer

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...?


Sunday, April 11, 2010

just finished a colpits oscillator for the DC Rx

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.


Monday, April 05, 2010

QRSS receiver up and running

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.

Friday, April 02, 2010

stage one prototype working

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.

Monday, March 15, 2010

more work on the DC Rx

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

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

Wednesday, March 10, 2010

I have mail

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 =)

Sunday, March 07, 2010

More work on QRSS DC Rx and a photo

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 =)



Monday, March 01, 2010

Making a band pass filter, or I hate toroids

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.



Thursday, February 04, 2010

First perl module

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...

Thursday, January 07, 2010

First Adelaide Perl Mongers social meeting

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.