recycled steerable dipole

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 ...

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

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.

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

New warning system for solar storms

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

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

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.

73,

Kim

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 =)

73,

Kim, VK5FNET

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

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.

Thanks,

Jonathan
AF6YF

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.

Kim VK5FNET

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...?

Kim VK5FNET

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.

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 =)

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 =)

72,

Kim VK5FNET

VK band plan

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

Foundation License limitations and restrictions

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

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

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

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