AmateurRadio.com

This weekend I have managed to get the FreeDV program working successfully and made a couple of QSOs on HF.

FreeDV has received a fair degree of publicity recently and is a GUI application for Windows, Linux and MacOS (other platforms are in development) that allows any single side band radio to be used for low bit rate digital voice communication.

I was primarily interested in it for possible use on VHF. It is hoped that the recently introduced 146-147MHz allocation available in the UK to full licence holders (via a Notice of Variation) will be used for digital mode experimentation. I have been constructing a data mode interface for use on the old TR9000 since it can operate on these frequencies but I decided to try the FT857D on HF to get an understanding of the program.


With FreeDV speech is compressed down to 1600 bit/s then modulated onto a 1.25 kHz wide 16QPSK signal which is sent to the mic input of a SSB radio. On receive, the signal is received by the SSB radio, then demodulated and decoded by FreeDV. The appeal being communications should be readable down to 2 dB S/N, and long-distance contacts should be possible using QRP power.

There is a lot of information. videos and guides available on the FreeDV website but the basics are straightforward. The computer requires two sound cards to handle the audio to and from the radio and the speaker/headphones and microphone. One method is to use a USB 'gamer' headset but since I already had a spare PC headset with 3.5mm plugs I opted for a cheap plug in USB soundcard (as detailed below)


Once the audio devices and PTT control are installed and configured within FreeDV it is a matter of monitoring a frequency (in USB) and hopefully you can send and receive.

So far I have only managed two QSOs with Trygve (LA6UOA) and Fabrice (F4FPG) on 14.236MHz with both the audio was clearly understandable but did suffer from the odd breakup and stutter. This was probably due to the laptop being used rather than an issue with the signal as the FreeDV needs a reasonably powerful machine with a decent amount of memory.

The software is very picky, several times the audio device settings have been forgotten or it has come up with a cryptic error message:

../src/msw/bitmap.cpp(846):assert "image.IsOk()" failed in
CreateFromImage(): invalid image

This is a known issue with the Windows version and the solution is to manually remove all of the FreeDV settings from the registry. The full details of how to edit the registry are in the GOTCHA section of the FreeDV site. Editing the registry is not recommended to the inexperienced person so is not a great solution and when starting the program backup after this fix requires reconfiguration of callsign, sound card and PTT settings again.

Despite this setback it is an excellent and exciting new mode. Both Trygve (LA6UOA) and myself were first timers when we had our QSO and we were like excited school children once we were able to converse successfully. Fabrice (F4FPG) was an old hand at it and I thank him for allowing me to briefly interrupt a QSO he was having with another UK operator who I could not hear.

I would recommend using K7VE's QSO Finder website http://qso.k7ve.org/ to see who is monitoring and on what frequency as well as passing hints in real time.

I doubt anyone missed the recent FTDI driver controversy.

The Scottish company Future Technology Devices International (FTDI) released an updated version of their USB-to-Serial driver for Windows on their website late September and last month the driver became available via Microsoft Windows Update. It soon became apparent that these new drivers could 'soft brick' counterfeit and software-compatible clones of their chips by re-writing the USB product ID (PID) to "0000". This action prevents the chip from being recognised by drivers of any operating system, effectively making them inoperable unless the PID is changed back. This clumsy and ill thought out measure was intended to protect its intellectual property.

The ability to reprogram the USB Vendor/Product IDs is a feature of FTDI devices offered to equipment manufacturers and so most bricked devices could be reset by using the downloadable FTDI utility.

Obviously there was much outrage from the hobbyist community and FTDI were roundly criticised and as a result the malicious driver was supposedly removed from the Windows update system.

Or so I thought...

I am currently constructing another data mode interface for some experiments with FreeDV. It requires the usual PTT control driven using the RTS line from a serial port. I purchased a couple of simple TTL level interface boards on eBay which claimed to use FTDI chips.



I built up a little scrappy veroboard circuit with an open-collector drive transistor and plugged into the shack PC and everything seemed okay as this PC already had an older FTDI driver installed.

I am using another computer for the FreeDV experiments and plugged the board into this thinking it too already had a safe FTDI driver installed but instead it brought up the installing driver dialogue and appeared to go online and download drivers and install them. I really didn't pay much notice as I wasn't too worried as any malicious drivers had supposedly been pulled and sure enough after installation everything appeared to work, the port appeared in device manager.

I unplugged the board to make a slight change and was surprised when I plugged it back in the PC the driver installation dialogue reappeared followed by an error message saying driver couldn't be installed and contact the manufacturer.

The serial port now appeared in the device manager with a yellow exclamation mark saying no driver installed error 28. Examining the device details showed that the VID was still 0403 but the PID was 0000 it had been bricked! Unfortunately not soft bricked as I have been unable to reset the chips PID using the FTDI utility.

I am not exactly sure what has happened but still a case of beware when it comes to FTDI devices and I shall be avoiding them from now on.

Back in January when I took delivery of the FT857D I reorganised the shack, disposed of lots of surplus junk and the resulting layout has served me well for most of the year.

As I've acquired more equipment I have found myself struggling for space and the cluttered workbench has prevented any proper construction.

Following a rearrangement in the house I had a spare 'desk' which I wanted to make of, so the plan was to move the workbench and put the new desk next to the existing desk. I had some bookshelves which were being used inefficiently and I almost threw them out but decided to make use of them by cutting them down and modifying to make new shelves to sit on the back of the desks.


I had another clean out and the remaining junk is now in large plastic storage boxes under the desk should it prove useful one day. It is still a little cluttered but I have much more room with proper access to my books and magazines.


 It is a work in progress, but it is a much better place to work and operate in.

Last weekend South Kesteven Amateur Radio Society (SKARS) operated the GB2FFC special event station at the First Foston Scout Group for the 2014 Jamboree on the Air (JOTA) weekend.

JOTA is an annual event in which Scouts and Guides all over the world make contact with each other by means of amateur radio, giving them an opportunity to experience wireless communication and electronics.


This was a first for both SKARS and the Scout group and we set up a SSB voice station and a data mode station primarily running PSK. The QTH was the Scout hut in the village of Foston, between Newark-on-Trent and Grantham (IO92PX)

Nigel (M0CVO) and Sean (M6ENN) ran the SSB voice station as well as supervising the popular Morse key trainer. This allowed the children to tap out their names using a crib sheet and gave them a certificate to acknowledge their achievement. Working voice proved challenging due to the high noise level in the hut due to the other scout activities. Despite this they still managed to work stations mainly on 20 and 40m. Nigel ran a Kenwood TS-480SAT into one of his own M0CVO DBD-2040 loaded dipoles at approximately 100W



I operated the data station consisting of my FT-857D and interfaces connected to a laptop running PZTLog feeding a M0CVO Magitenna at 30W. I also had my Czech morse key connected to the TR9500 acting as a sounder and they really like the military style key.

Explaining the PSK datamode and what the program was doing to young children was quite challenging. The Scout group were also running JOTI (Jamboree on the Internet) which consisted of laptops running an IRC chat application allowing world wide groups to talk to each other so the distinction between that and the slower PSK station was a bit difficult for some of them to grasp. Thankfully there were two very intelligent and enthusiastic Scouts who got the idea and understood the QSO process and were soon explaining it to the other Scouts leaving me free to type and push the macro buttons. One of them described it as 'awesome!'



GB2FFC ran from 09:00-15:00 UTC on the Saturday and 12:00-15:00 UTC on the Sunday and made 88 QSOs in total, mostly other amateurs but we did manage a number of other JOTA stations in both modes. The whole event was great fun and we were made very welcome by the Scout group. The enthusiasm was infectious so hopefully it will be the start of a regular annual club event helping out the Scouts for JOTA - plans were already being sketched out for next year, maybe involving camping!

Here are the PSK QSO maps for the weekend. Saturday was on 20m and 15m and were just European, Sunday I was operating mostly on 10m hoping for some transatlantic contacts, and did make a couple in the short time we had - didn't quite manage to connect with some South American and Asian stations but they could be seen and decoded to the delight of the children.

 

I now have a full licence and a new call sign M0NRD.

I sat the advanced level examination held during the RSGB Convention on the 12th October. The results were due at least six working days later so wasn't expecting to know how I had done till this week so I surprised when the certificate arrived on Saturday morning and was over the moon to discover I'd passed with a distinction.

I only decided to apply to sit the exam last month. Regular readers may have missed the announcement as it was an after thought at the end of another post.

I became a licensed ‘foundation level’ radio amateur last September (M6GTG) and an ‘intermediate’ (2E0NRD) in May this year. It was a bit of a bold decision to attempt the final stage as I hadn't been actively studying for it. There have been many people who have progressed in a shorter time but going through the levels in just thirteen months is a big undertaking especially when time and concentration is taken up with work, career and domestic commitments.

After a cursory glance at the syllabus and a quick leafing through the RSGB Advance! book I had decided while there were quite a few areas that I didn't know in depth the electronics theory and mathematics were okay due to my higher education background (though it has been 26 years since I left University) so I just needed to fill in the blanks.

After posting off the application the plan had been to spend the month going through the book, learning, refreshing and revising the subjects as necessary. Of course I got sidetracked and distracted so it got left it to the last minute, well in fact to the week before the exam.

As soon as I started studying properly I soon realised I'd seriously underestimated the amount of details and facts that I need to understand and recall. I knuckled down and despite doing full days at work I studied in the evenings, making notes, working the questions on the Hamtests website and in the QADV program and gained confidence of getting at least the 60% pass rate. I tested myself on the QADV practice papers and mock papers on the RSGB website and seemed ready.  

I had intended to be at the RSGB Convention proper however I agreed instead to spend that weekend at the Mother-in-laws in Cambridge and drove over to Milton Keynes in thick fog on the Sunday morning.

The actual exam seemed reasonable there were a few head scratchers and several questions on topics I suddenly found myself unsure of. I took my time deliberating and checked every single 'licence condition' question against the supplied licence document even if I thought I knew the answer. Double and triple checking questions, values, calculations and answers and with 10 minutes of the alloted time remaining I had filled in the marking sheet and made a quick exit in time to get my Sunday roast dinner.

I had left confident and reasonably happy but over the next few days doubt inevitably started setting in. I kept remembering questions.. had I got that one wrong? I resisted the temptation to check the text book and keep thinking well it is only 60% I need...

To achieve a distinction was very satisfying, a lot of people have said they expected me to walk it but self doubt and a lack of self confidence is something I have suffered from for many years. When I was a spotty student I would probably have agreed but now an overweight, slightly befuddled middle aged man with greying hair you do have your doubts.

I would like to thank all those people who have congratulated me and those who have encouraged me along the way and wish everyone studying and taking the exam in the future the best of luck.

The shack has gained a couple of 'new' radios, one of them look familiar?


It is the Trio/Kenwood TR9500 that I repaired last month for a fellow club member. Having no transmit audio I'd replaced a faulty transistor in the microphone pre-amp. Subsequently it's owner reported it was still misbehaving and locking up in transmit mode.

I'd offered to give it another look but the owner decided to cut his losses and wanted shot of it. He had just purchased a nice new radio at the National Hamfest and was also selling a 2m Trio/Kenwood TR9000 multi-mode set to make some room.

I liked the look of these pretty sisters and got both of them for a very reasonable price, the TR9500 costing just £10 in lieu of the previous repair work. I collected them at the weekend and got around to checking them out last night.


The TR9000 is a lovely compact rig, the case has the odd scuff but the front is in good condition and has cleaned up nicely. I just need to attend to the microphone plug as it wearing the ubiquitous piece of brightly coloured insulating tape. It is fully functional and I made a few contacts on it during last nights 144MHz UKAC. It is nice sounding and seems to have a good sensitive receiver.

The troublesome TR9500 has been back on the bench and connected to a dummy load and my X-50 dual-band collinear and I cannot find anything wrong. The ALC 'issue' I suspected was a red-herring, the audio does cuts out and the S-meter goes to S9 but only when the RF gain knob is turned to minimum not maximum as I'd thought, the same thing happens on the TR9000.

It is entirely possible the fault reported by its previous owner is intermittent (a bad joint, sticky relay etc) It is also a possibility that RF was leaking back in the rig causing it to lock up. I plan to use it in anger maybe during next weeks 432MHz UKAC especially if the receiver proves as sensitive as that in the TR9000. 

As I mentioned the National Hamfest took place recently and since it is local to me I decided to go along on both days. The Friday was by far the busier day with lots of sellers in the outdoor flea-market with a genuine 'buzz' which seemed lacking on the Saturday, there were a lot less sellers outdoors.

The main hall left me a bit underwhelmed, the layout seemed a bit messy and some areas were cramped while others seemed to have acres of spare room. It was also very hot in the main hall especially on the busy Friday, however it was still an enjoyable couple of days and met up with some fellow tweeters and operators. 

My purchases were modest and as well as the usual connectors and cabling I picked up a nice as-new 7A regulated linear power supply, a foot switch, a replacement satellite Quad-LNB, a very sorry looking 70cm linear amplifier and picked up one of those lovely Czech morse-keys for when I brave doing the code!

I also picked up this little 2.4GHz B/W video monitor for a whopping £1 and it works a treat. I have a number of 2.4GHz wireless security cameras (purchased back in 2009) intended for a PC-based PVR CCTV system but the whole PC system proved unreliable so they are sitting idle. This little monitor can receive on the four standand channels and as a bonus runs off 13.8V so ideal for sticking in the car and driving around the local housing estate eavesdropping on other similar cameras - I am joking of course!


The very sorry looking 70cm linear amplifier is a Tokyo Hy-Power HL-60U. I found it hiding away in a box of junk on one stall and after a bit of haggling got it for a fiver! From its appearance I really didn't expect it work, especially since the warranty seal had been broken. I wasn't too bothered about the power amplifier I was far more interested if the built in GaAsFET pre-amplifier still worked.


Getting it on the bench I opened the case, expecting to find it plundered and butchered and was pleasantly surprised to find the insides looked almost pristine. I think the main PA transistor may have been replaced, but while it looks a bit messy the flux resin around its joints looks the same as other areas of the PCB so not sure. It looks slightly different internally to some another photographs I found on line and I have searched the web for a manual and schematic with no joy. Tokyo Hy-Power went bankrupt last year and the website and precious data downloads have all but disappeared.


As it looked intact with nothing missing I connected up the dummy load, power meter and fed the input from one of my Baofeng handhelds. It powered up and was giving 15W out for a measured 3W in with no distortion on the audio, so far so good. However after connecting up the FT-857D and slowly increasing the input power is became apparent that 15W seemed to be about the limit of its output, not the 60W as promised.

Removing the dummy load and putting it on the X-50 antenna I had a listen around for weak stations to checked the operation of receive pre-amp and it worked! Should prove useful for the 70cm contests.

Weather balloons have been routinely launched into the atmosphere for many years by government and commercial organisations for the purpose of scientific and meteorological observations and research. Hundreds are launched daily around the world, using predominately renewable Hydrogen as the lifting gas.

These balloons invariably carrying radiosondes, a battery powered telemetry instrument package to measure various atmospheric parameters and transmit them to a ground receiver. Worldwide they operate on radio frequencies around 400MHz and 1680MHz.

Last year I discovered the hobby of High Altitude Ballooning, where enthusiasts send up their own balloons loaded with experimental payloads and radio telemetry trackers using low power transmitters and amateur radio data modes and frequencies. I have since had a great deal of enjoyment receiving and decoding these as well as developing my own payload.

I decided last year to also try my hand at decoding the commercial radiosondes. Reception of the telemetry signals is relatively straightforward as they are of higher power than the hobbyist transmitters and decoding can be done by the Sondemonitor program from COAA available to individuals to produce graphs and charts of temperature, pressure, humidity as well as the location (if transmitted) and height of balloons.

The software is available for a 21 day trial but when I attempted to install it I was thwarted by a licensing issue caused I believe by installing trial versions of COAA's ShipPlotter and PlaneSpotter programs in the past, despite this I still decided to purchase a software licence for the princely sum of €25.

However this was just before the Christmas upheaval and the dismantling of my receiving set up and so it got mothballed and I have never got around to using it till now.

It was quite by chance that I was flicking around the SDR yesterday using my original (Version1) FUNCube Dongle PRO when I spotted a Radiosonde signal on 404.2MHz, my interest was piqued. (It should be noted the later FUNCube Dongle PRO+ unfortunately has a coverage gap on this frequency so cannot be used)

I connected to my magical HAB antenna and using SDR# and the Sondemonitor program I received and decoded my first radiosonde early this morning and a second flight around noon.


The program produces some interesting graphs showing temperature, humidity, pressure and other measurements during the ascent and after the balloon burst, as well as Tephigrams.


 
I am not sure where these balloons are launched from. The Radiosondes are identified by the software as Vaisala SGP models (but have no GPS data?)  Checking the Vaisala website there are a number of devices and one downloadable document is a comparison of the Vaisala Radiosondes made by the UK Meteorological Office in 2013 (pdf file) which mentions a site in Camborne in Cornwall, but I have also seen mention elsewhere of a site in Larkhill on Salisbury Plain.

The Met Office document also hints that the Radiosonde currently used by them is one of the Vaisala RS92 range, indeed the RS92-D appears to be a device which has no on board GPS and would fit with the GPSless decodes I have made.

Definitely another interesting radio diversion and if you are interested then reception can be made using RTL-SDR receivers as this tutorial on RTL-SDR.com demonstrates, but bear in mind the demonstration/tutorial shows GPS information being received which I have not seen on either of the two launches.