Monday, November 29, 2010

Minor update for KComm

I have just uploaded a minor update to the Windows version of KComm, my logging and digital modes program for Elecraft K2 and K3 transceivers. Version 1.91 now supports the ability to specify the receive and transmit sound devices using the device name rather than a number which Windows appeared to change at will.

I had been unable to find a way to get the sound card device names from Windows using Free Pascal and happened to mention this during a discussion in the Yahoo digital modes group about how so many sound card programs seemed to lose the sound card settings under newer versions of Windows. Patrick, F6CTE, who is the author of MultiPSK, very kindly responded with some Delphi Pascal code to list the installed sound devices. This has now been incorporated in KComm and makes sound card selection much easier - especially for me as I am always adding and removing USB audio devices on the shack computer which changes the numbering.

My grateful thanks to Patrick for his help with this little problem.

Sunday, November 28, 2010

Jam tomorrow

I have not been keeping up with the development of the controversial ROS digital mode as for reasons given in earlier posts I decided it was not something I wanted to use. However a recent post in the Yahoo digital modes group brought to my attention a development that seems rather alarming. The ROS software has recently included an anti-jamming switch the purpose of which is described as "improves rejection against strong CW and Beacons interferences."

Polite usage of the amateur bands require that you check the frequency is in use before making a call so no-one should be jamming anybody. Furthermore, no-one should be using ROS in the CW or beacon sub bands. So what exactly is the purpose of this switch and why should anyone need it?

Perhaps an inkling of what may be going to happen can be drawn from some of the comments relating to the performance of the anti-jam switch, for example:
  • "The New ROS/2000 passed the test successfully during the CW Contest last weekend."
  • "More test with the New ROS/2000 in other hostile environment. This time during a PSK63 Contest on Sunday."
As I said all along (indeed, this was my original objection to the use of this mode) ROS is just too wide for use in the narrow digital allocations of the HF bands. There just isn't the space for it, unless it remains a niche, occasionally used mode, which clearly its developer and supporters don't intend it to be. As another comment in the ROS forum states: "The bands will fill up once people realize how good this mode is."

The development of anti-jam techniques suggest that ROS is being readied to engage in war with users of other modes. When users can't find a clear frequency they will just operate on top of other modes. The principal claimed advantage of the wide ROS mode is that it enables contacts to be made under similar weak signal conditions to JT65A but that it permits keyboard chats to take place rather than the basic exchange of signal reports and locators. So it appears that a vast swathe of spectrum space is going to be made unusable for other modes simply so that people can exchange brag files.

We need strict regulation of digital modes on the amateur bands. The days of gentlemen's agreements are over. There are too many modes competing for limited spectrum space, and too many hams who aren't gentlemen.

Wednesday, November 24, 2010

Tiny transmitter

I think I may have discovered one of the best kept secrets in radio. I have been thinking, off and on, about how to make a very low power 2m FM transmitter in order to get weather data into my APRS system wirelessly. A circuit using the Motorola MC2833P chip is quite easy to build, and I even have one in my parts box, but a custom crystal to multiply up to 144.800MHz would cost about £25 to be made which just isn't worth it.

One day I was browsing looking at various APRS articles and came across a tracker someone had built using a VHF transmitter module from Radiometrix. I had come across this site before but thought that a) these modules were only for transmitting digital data not the AFSK that we use, b) they were not manufactured for amateur frequencies and c) they were not available in one-off quantities for individual private purchasers. I submitted an enquiry, stating that I was interested in purchasing one TX1 low power (10mW) module on 144.800MHz if the price was within my amateur budget, and was amazed to be informed that they would be happy to offer the module for £13.00 plus carriage and VAT, with a lead time of five days. In total it came to not much more than £20 which is amazing considering many professional electronics suppliers specify a minimum order value greater than that.

The picture of the module is much larger than it actually is - the pins are the standard 0.1in spacing. As I am nowhere near actually needing to use it at the moment, I hooked it up on the breadboard to give it a quick test. The module does indeed accept an audio input: as described in the data sheet you should bias the input pin and then feed it with audio at a couple of volts amplitude via a blocking capacitor. I lashed it up to my FoxTrak APRS tracker and a braaap was received and decoded by my 2m APRS gateway which was enough of a test to be going on with.

There are several other products with interesting ham radio applications on the Radiometrix website. The HX1 is a high power (300mW) version of the module I bought. With the addition of a PA I could turn my FoxTrak into a standalone tracker. Even by itself it would probably have quite a decent range from the fell tops. Also of interest is the SHX1 which is described as "a small multi-channel 25kHz narrow band VHF transceiver with up to 500mW RF power output, usable for 144MHz band amateur applications." I think you could build a little hand-held transceiver with one of these, just for fun.

Many of these products aren't in the online shop so you can't find out the price or buy online, which is probably just as well as I could see myself ordering some more of these toys for something to play with over Christmas. I would certainly be interested to hear from anyone who has used, plans to use or has some ideas for using any of these little radio modules from Radiometrix.

Tuesday, November 23, 2010

Free Lake District Wallpaper

I have received many favourable comments whenever I have posted pictures from some of my local walks in this blog. I'm sure this has more to do with the beauty of the landscape than my skill as a photographer or the quality of my camera. Still, your appreciation of my pictures gave me the idea that I could use some of them to create desktop backgrounds or wallpapers that I could give away as promotional freebies from a website that needs more visitors. Here's a sample of one of them.

If you would like a view from the English Lakes to brighten up your desktop, please visit Free Desktop Wallpapers. I hope you find something there you like. And please feel free to post the link anywhere it might be seen by others who would enjoy the images. Every little helps!

Saturday, November 20, 2010

WOTA day

What a day it has been for activity in the Lake District fells! Although the day isn't over the light is beginning to fade as I write this and I'm guessing there won't be any more activations today. But a quick count of the spots on the Wainwrights On The Air website shows there have been a total of 22 different fells activated by 6 different people which is probably a Wainwrights record.

At times the spots were coming so thick and fast that there was a danger of missing someone because you spent too long calling another station. And the fell-top stations had a hard job finding a clear frequency. Many had to QSY two or three times from their original chosen frequency because they landed on top of someone else's contact. Perhaps we need to consider moving to 70cm for WOTA?

I myself made 16 contacts and added 7 new summits to my chaser total. I wish I could have been out on the fells myself to gain a bit of elevation and work some of the more distant ones. But this has still been my most productive day of WOTA chasing. Thanks to Phil G4OBK, Geoff GM4WHA, Phil M0AYB, Richard G1JTD and Colin G4UXH for the contacts. Visit Phil G4OBK's Wainwrights blog where he will no doubt be posting an account of today's activity with pictures shortly.

Friday, November 19, 2010

A little RF goes a long way

In this case, 5W of WSPR on 40m to a bent attic dipole. Not, perhaps, as impressive as M0XPD's results with 50mW on 30m. But it's still nice to be heard on the other side of the planet.

Visitors Book Spam

I received two emails this morning from people who had received spam from someone who claimed to have got their profile from my website G4ILO's Shack. I don't have user profiles on my site. The only place the spammer could have got the email address is from the visitors' book, and sure enough when I checked both these people had made entries in it.

The visitors book uses the common trick to obfuscate the email address of encrypting it and using a Javascript function to display it in the user's browser. This worked on the assumption that spammers email harvesting bots simply grabbed the raw HTML pages and didn't use an actual browser so the Javascript didn't run and the email addresses remained hidden from the spammer.

I guess it was only a matter of time, given that computers are now much faster, before spammers started using embedded web browsers to load web pages before scanning them for email addresses. That is the only explanation I have for this. I have removed the display of the email address from the visitors book comments entirely, which should prevent this happening in future.

Some visitors ask questions or mention something interesting in their comments and I thought it would be useful for those who read them to be able to reply if they wish. But I doubt that many people take advantage of this so removing the email address is probably no great loss.

Tuesday, November 16, 2010


The winds of economic change are starting to have an effect on our online business. Because of that I am spending a lot more time on the computer trying to maintain our search engine positions and think of new revenue streams, with the consequence that I have less time or enthusiasm for blogging and other radio-related activities.

The only noteworthy item of radio news at G4ILO has been the acquisition of an SCS Tracker / DSP TNC for HF APRS packet. It is shown in the picture sitting atop my K2. When I find the time, I will write a review of this TNC for my main (non-blog) website. For the time being, all I will say is that I did a side by side comparison with the best of the PC sound card decoders and it was very quickly apparent that the SCS TNC decoded many stations the sound card software didn't. Considering what it cost, I'd have been very disappointed if it hadn't.

Thursday, November 11, 2010

Curse Yaesu

... for making the power connector for the FT-817 a nonstandard and apparently unique size. I sacrificed the power cable of a multi-voltage wall-wart which had a set of interchangeable tips to make a cable I could use to run the '817 from my lab bench supply for an experiment. One of the tips looked to my eyes exactly the same as the one on the Yaesu charger, even down to having a yellow plastic insulator at the tip. But stupid me I didn't think to check it would actually go in before severing the cable from the wall-wart and now I find that it doesn't. So not only did the wall-wart lose its cable in vain but I now can't do my experiement, since it would have taken longer than the '817's woefully inadequate batteries would permit. Grrr!!

I can't even find an FT-817 power cable on eBay.

Wednesday, November 10, 2010

Tracker trouble

Today was one of those perfect days you sometimes get in winter. It was too good to stay indoors, especially as rain is forecast for tomorrow, so after lunch I packed my APRS tracker and Motorola GP300 in my rucksack and went for a short hike up Binsey, one of the Wainwright hills in the northern Lake District.

There had been a frost overnight and even now in the early afternoon the temperature was only a degree or two above freezing. Looking towards the central Lake District across Bassenthwaite Lake you could see the distant hills were covered with a light dusting of snow.

On the way up to the summit of Binsey I observed that my tracker was not transmitting. The tiny red LED on the GPS was flashing to say the receiver was working but the GPS OK light on the tracker itself was out. If I switched the unit off and then on it would send its position as soon as GPS lock was obtained, but that was usually all I got. When the beacon was sent I also heard a few noises from the Motorola receiver. None of this had happened during testing in the shack, but a cold fell-top is not the ideal place for troubleshooting. The lack of position reports received during my walk on Sunday was probably not due to conditions

On my descent I enjoyed the view of the snow-dusted Skiddaw range against an almost cloudless blue sky. To think, some people are stuck in an office on a day like this! (OK, I know, I don't have to rub it in!)

Back home I connected up my tracker on the bench and it worked perfectly again. I then put it in my rucksack as it had been while I was out and it started to behave as it had while I was out. Some braaps were accompanied by a sort of farting sound that was probably RF feedback. I'm pretty sure RF is getting in somewhere and causing the tracker board to misbehave, but the question is: where?

I've tried moving cables about and clipping ferrites on the leads but so far I'm not sure what is the cause. I hate this kind of problem which can have you going round in circles thinking you've fixed it and then it recurs. I'm not sure yet if the RF is being picked up on one of the cables - both the PS/2 GPS cable and the curly Motorola cable are quite long for this application - or whether it is getting to the module directly since it is only in a plastic case. Perhaps I should try it in a die cast box. Any ideas?

Tuesday, November 09, 2010

Two new continents on 40m

I popped up to the shack after watching some evening TV and decided to have a listen to what was happening on JT65A on 40m. I tuned my K3 to 7.076MHz and had only been listening for a couple of minutes when I saw a CQ call from VK6BN appear on the screen. I only just managed to set up a reply before the start of the transmit period and you could have knocked me down with a feather when he came back with a report! We completed the QSO in the minimum 6 minutes.

I've been reported in VK before using WSPR, that's nothing unusual, but this is my first ever two-way contact with Australia on any band or mode and I'm pretty amazed to have achieved it on 40m of all bands using just 30 watts to my attic dipole. JT65A really is amazing!

As if that wasn't enough, I then worked KE1AF for my first contact with North America on 40m. So I shall be going to bed this evening feeling pretty pleased!

Monday, November 08, 2010

Autumn walk

Sunday was a fine but cold autumn day and Olga and I went for a walk near Loweswater. In my rucksack I took the Motorola GP300 and the FoxTrak APRS tracker. This is a somewhat more bulky arrangement than using the VX-8GR, however this hobby has for me always been more about providing a reason to build and tinker about with stuff than using the latest, most efficient technology and using this home-built tracker with a radio I bought for £1 at a rally is just somehow more fun than using Yaesu's latest gadget.

I had obtained a cable for the Motorola with the correct two-pin plug to make up an interface. I cut the tip off the 3.5mm jack so that inserting the plug did not cut off the speaker and I programmed a channel on the radio with 144.800 as the transmit frequency and 145.500 as the receive frequency. This meant that I could hear anyone calling CQ during the periods between transmitting position beacons. The downside is that the FoxTrak cannot tell if the APRS frequency is clear before transmitting. But many dumb trackers do that already because they don't have a receiver. In any case, the APRS activity level here is so low that the chances of a collision occurring are about the same as winning the lottery.

Although the path we walked along was quite high, this was not a very good location for radio. Only one position beacon was received by a gateway and I made just one voice contact - with Phil M0AYB/P activating the summit of Blencathra for WOTA. (Phil later went on to activate Mungrisdale Common which completed activations of all of Wainwright's Northern Fells. I'm doubly sorry to have missed contacting him there, but congratulations Phil on the achievement.)

Our walk took us down through the woods to the lake shore and then back to the car. The autumn colours were wonderful - my pictures don't really do justice to them. I expect most of the leaves have now gone. Last night there was a gale and this morning through the overcast we could see wet snow on the mountains down to quite a low altitude. I doubt that there will be many more opportunities for a walk like this before the end of the year.

Friday, November 05, 2010

Spot on

Having an interest in weak signal narrow band modes, not to mention APRS which requires you to park your receiver on a specific frequency, I have always wished that the frequency readout on my radios could be relied upon. The QRSS band, for example, is only 100Hz wide. If your dial reading is out by that much, you'll miss it completely.

Many people try to calibrate their transceivers using WWV but that is not often a very good signal over here, and what with all the other carriers around 10MHz - many of them locally generated - you can never be sure that you have tuned to the right signal. I have wanted an accurate frequency reference for some time so a couple of weeks ago, following a comment by QRSS enthusiast Steve G0XAR, I ordered an Efratom LPRO-101 rubidium frequency standard on eBay. It arrived in about a week.

The unit I bought cost about £50 and came with a plug for the 10-pin connector and a 24V switched-mode power supply. These second hand units are widely available. New, they cost over $1,000 even in quantity. They are used in cellular base stations and are manufactured to have a maintenance-free life of ten years. To ensure reliable service the cellphone network providers take the equipment out of service before the ten years is up after which it is presumably shipped to China for reclamation. The used units should have several years of life in them, especially in occasional amateur use.

Rubidium frequency standards work by locking a crystal oscillator to the very precise frequency at which the amount of light from a rubidium lamp dips due to a phenomenon known as the hyperfine transition. A synthesizer locked to a reference oscillator is swept through this frequency until the dip is detected. The LPRO-101 includes an oven for the reference crystal, circuits to detect the dip and lock the oscillator, an output that tells you when the unit is locked, and the frequency reference output at 10MHz. The connector also provides signals that can tell you the state of health of the rubidium lamp. Once that fails you may as well scrap the unit because it can only be replaced by the manufacturer at a cost far in excess of what you paid for it.

To use the LPRO-101 you could simply attach a 24V supply and connect a cable to the 10MHz output. However, it's useful to have a circuit that shows you when the unit is locked on frequency. I used one shown in an article by KA7OEI built up on a piece of Veroboard, which uses a dual-colour LED to light red when the reference oscillator is unlocked and green when it is locked. You can see the circuit board inside the partially assembled case.

The voltage regulator and crystal oven inside the LPRO-101 generate a lot of heat so the unit is intended to be mounted on a heat sink. I purchased a Hammond extruded aluminium case to use for the project, which should provide reasonable heat sinking for the module.

One thing I learned from researching on the internet is that the LPRO-101 will run cooler when operated from its minimum recommended supply of 19V. This just so happens to be the output voltage of the power supply for an old Toshiba laptop whose screen failed so I decided to use that instead of the 24V supply that was sent by the seller.

The other thing I learned is that the rubidium lamps wear out with time. When they are made, the manufacturer ensures that they contain sufficient rubidium to achieve the stated maintenance free life of ten years, so the expected life in continuous use would be ten years less the use it has already had.

If I ran the unit all the time my rig is on - for example as an external frequency reference for a transceiver - then it is going to fail sooner or later. If I only use it for frequency calibration purposes, switching it on only when needed, then it will probably outlast me. The TCXO in my K3 is pretty stable so I should be able to obtain adequate accuracy for my purposes by manually calibrating the master oscillator using the rubidium standard and repeating this as often as necessary. How often that turns out to be, we'll see.

Here is the finished unit. Annoyingly, I messed up the front panel of the rather expensive Hammond case. Originally I had intended to use an SMA socket for the output but I didn't get the holes for its two mounting screws in the right place and after filing to fit it looked unsightly. So I fitted a BNC socket instead which is what I should have done in the first place. Unfortunately you can see the two holes for the SMA mounting screws either side of the BNC socket. So my frequency standard doesn't look quite as professional as this one built by DL2MDQ. Oh well, it's only a piece of test equipment!

Thursday, November 04, 2010


I don't know how long it has been around but I only discovered this online propagation prediction tool using the VOACAP prediction engine today.
It's very easy to use, and produces a nice chart showing the best times and frequencies to use to make a contact with a particular region. Of course, the predictions are based on the average expected propagation for the month, it won't tell you what the bands are like today, which is why it is better not to waste your time on tools like this and turn on the radio.

Wednesday, November 03, 2010

KComm updated

Today I released a new version of my logging and data communications program for Elecraft transceivers, KComm, on my website. The program is developed in Lazarus / Free Pascal and is released under the GPL.

Apart from numerous bug fixes and small improvements I have made in the months since the last release, the new version 1.9 allows the receive and transmit sound devices to be selected separately. This is something that is becoming increasingly necessary, though users will have to play "guess the device number" as I don't know how to find out the names of the sound devices in Free Pascal in order to display them in a list box. The program also supports the K3 "TB" command which allows it to get the text decoded by the K3 DSP in CW, PSK or RTTY modes and display it on the screen just the same as if you were using a sound card program.

Although I have given up developing ham radio programs in general, I am continuing to update and maintain KComm as it is the only one of my programs that I continue to use regularly. However this will be the last version for which I will be able to provide a compiled Linux binary. The screen of the old Linux laptop that I used to compile it has almost failed so I will not in future have a computer on which I can do this.

Tuesday, November 02, 2010

Being prepared

We Brits and our friends across the Atlantic may share a common language but sometimes it seems as if we live on different planets. One of the most obvious examples of this is that Americans sometimes seem to act as if Armageddon could happen at any minute, something that doesn't seem to cause much lost sleep over here.

Perhaps I'm jumping to the wrong conclusion based on the higher emphasis given in the USA to the use of ham radio for emergency communications. Read some issues of QST these days and you might think that "emcomms" is what amateur radio is really all about. Many American hams maintain "go kits" - portable radio stations that they keep charged up and ready to go the moment they are needed. Over here we have something called Raynet, but I get the distinct impression that it is a bunch of people who would like to use ham radio to help in an emergency rather than a volunteer emergency service on the lines of, say, Mountain Rescue that has a clearly defined purpose and meets a genuine need.

In his latest blog "Smoke Curls" Jeff, KE9V recently posed the question of whether a portable QRP HF station was really useful in the context of emergency preparedness. Most of the replies seem to illustrate the extent to which the thought of a major disaster is never far away from the American consciousness. My comment that the only benefit I could see in having battery powered HF ready to use was so I could take advantage of the noise-free bands while the power is out - which in fact I did during the outage that occurred during the local floods a year ago - probably seemed rather flippant, though that wasn't the intention.

My opinion is that emergency communications is a job for the experts and the last thing they need is a bunch of amateurs trying to help but more than likely getting in the way. The Cockermouth floods were the nearest I have ever come to being directly affected by a disaster and it never even entered my head that as a radio amateur I might be able to help. As for needing HF or any other kind of ham radio for personal emergency communications I still feel the likelihood of something happening in which my radio gear might end up being my only means of getting in contact with anyone I needed to is so remote that I'd cross that bridge if I ever came to it.

I would never assemble a "go kit". And if I did, I know for sure that I would forget to charge the batteries or raid it for parts I needed for something else so it would never work in the unlikely event it was needed.

Is there a cultural difference between us and Americans in this regard, or is it just me?

Monday, November 01, 2010

Taking part

On Saturday I blew the dust (literally!) off my K3's microphone. After I had finished sneezing, I started making some contacts in the CQ WorldWide SSB DX Contest.

This was not intended to be a serious competitive effort. My intention was to spend all of the time I could spare that weekend making contest contacts and see how many stations I could work. I spent about an hour on Saturday morning before going with Olga to the garden centre, and a couple of hours in the afternoon. On Sunday I was up earlier than normal because the clocks went back overnight, so I operated for about three hours in the morning before lunch. I had intended to do some operating in the afternoon as well but the three hours in the morning had left me feeling a bit tired and stiff so I went for a walk after lunch and then fell asleep on my return home. Getting old is my excuse!

I made a total of 154 contacts in 43 different countries and 4 continents during my six hours or so of operating. The detailed breakdown, for those interested, is shown in the screen grab of the contest statistics dialog from KComm (the Extra field shows the number of CQ zones.) This would give me a claimed score of 17,487 points if my calculations are correct, which by comparison with last year's results would place me well down the second half of the All Band Single Operator Low Power Unassisted results table.

This was the first time I had made such an effort for an SSB contest. Until now I hated turning on the radio during big SSB contests because the bands sounded like bedlam. But I had never tried with the K3 before. Instead of a mush of intermod, splatter and AGC pumping I could hear everything clearly. Sometimes I could hear two or three stations on the same frequency simultaneously, one in the foreground and a couple in the background. And the superb DSP filtering made it easy to shut out close-by stations so I could copy a weaker one. I often had the passband down to 1.8kHz and copy was still crystal clear.

Initially I started off just working the loud ones because I didn't want to waste the serious contesters' time by making them struggle to hear my call. But I found there was no hard and fast rule relating how strong a station was with whether they heard me. One Finnish station, 10dB over 9 with me, just kept on calling as if I wasn't there. But many weaker ones came right back to my first call.

Frustratingly, a significant number of stations came back to me as "Golf 4 Lima India Oscar" - exactly the same error that was made when I ordered my QRSS beacon kit a couple of weeks ago. What is it about my call? This doesn't happen on CW (though I used to get replied to as G3ILO very often as the holder of that call is a well known QRP CW operator.)

Conditions didn't appear to be very good this weekend. I'd hoped to hear some interesting DX on 10m but I heard hardly anyone at all on the band. As always, 20m was the liveliest band, but I made almost as many contacts on 15m, probably because the QRM was less making it easier to make contacts.

I didn't work any DX and I only worked one all time new DXCC entity - Svalbard, JW5E. I did hear a VK on 15m on Sunday morning but he had a big pileup going and after trying for about five minutes I decided not to waste any more time and move on.

Despite my unspectacular results I thoroughly enjoyed my few hours in the CQ WW DX SSB contest. No doubt and other online forums will be full of grumbles about contests taking over the band for the entire weekend, the only time working people can get on the air etc etc. But if you can't beat them, why not join them?

My feeling is that contesting is one of the many different activities you can pursue and to get the most from the hobby you should try as many of those different activities as you can. As this post has hopefully shown, having indoor antennas is no obstacle to working a decent number of stations and earning a respectable score for the time spent. It's not the winning, it's the taking part that counts. I certainly felt like a real participant in this radiosport event and I look forward to seeing my call in the results table next year.