A CAT5 fed PA9RDT antenna for VLF

This blog has reported on the excellent work by Roelof, PA0RDT on active antennas. In a note earlier in the year Roelof reports on an other variant of the design.

"Michael Oexner has had good results with a mini-whip E-field probe I build for him. The circuit diagram is below. The feedline is CAT5 network cable.

"Note that the RF-isolating transformers in the signal path are not correct. I have used MCL TT 1-6 parts, rated for 0.004 - 300 MHz at the -3 dB points. The common mode chokes are not optimum, as I used the parts I had on hand. Type 75 or 77 ferrite should be better.

"Michael used a PERSEUS SDR, which has a noise figure of about 25 dB at 9 kHz. This is due to the fact that there is also a RF-isolating transformer in the signal path.

"It is amazing that with this not optimized set up it was possible to have good reception over a 72 km path. The actual capture area of the antenna is 30 x 40 mm single sided copper clad PCB.

There are quite a few people around with a PERSEUS SDR, who are probably interested in receiving Stefan's (DK7FC) signal on 8790Hz (ed- yes Hertz). So a simple antenna design might help. "



Stewart/G3YSX

Chinese Fake Electronics

Recently there was a mention in Sprat of fake 2SC1969 transistors being supplied from China. Leon Heller, G1HSM, pointed out to readers of the GQRP list that there's a lot of it going on, largely due to the current shortage of many components. Sparkfun has an interesting account of their investigation of fake AVR chips on their web site: www.sparkfun.com/commerce/news.php?id=350

Stewart/G3YSX

GCHQ - The Uncensored Story

GCHQ - The Uncensored story of Britain's Most Secret Intelligence Agency by Richard Aldrich is a well written book that should be of interest to many members of the amateur radio community, if only because much of the GCHQ SIGINT input is captured by radio intercept.

GCHQ is the successor to the famous Bletchley Park wartime code-breaking organisation and is the largest and most secretive intelligence organisation in the country. During the war, it commanded more staff than MI5 and MI6 combined and has produced a number of intelligence triumphs, as well as some notable failures. Since the end of the Cold War, it has played a pivotal role in shaping Britain's secret state. Still, we know almost nothing about it.

In this ground-breaking new book, Richard Aldrich traces GCHQ's evolvement from a wartime code-breaking operation based in the Bedfordshire countryside, staffed by eccentric crossword puzzlers, to one of the world leading espionage organisations. It tells many dramatic spy stories that shed fresh light on Britain's role in the Cold War - from the secret tunnels dug beneath Vienna and Berlin to tap Soviet phone lines, and daring submarine missions to gather intelligence from the Soviet fleet, to the notorious case of Geoffrey Pine, one of the most damaging moles ever recruited by the Soviets inside British intelligence. The book reveals for the first time how GCHQ operators based in Cheltenham affected the outcome of military confrontations in far-flung locations such as Indonesia and Malaya, and exposes the shocking case of three GGHQ workers who were killed in an infamous shootout with terrorists while working undercover in Turkey.

Today's GCHQ struggles with some of the most difficult issues of our time. A leading force of the state's security efforts against militant terrorist organisations like Al-Qaeda, they are also involved in fundamental issues that will mold the future of British society.

For me the key takeaway is that pretty well any place where a Union Jack flys and a good many more places besides are likely to be listening sites feeding this SIGINT machine. Until relatively recently this involved men and women with headphones undertaking a very stressful, but boring job, a mixture that created a number of security risks described in the book. In modern times the remote site is more like a hoover sucking up spectrum for the big SIGINT machine in Cheltenham.

One of the more interesting example of GCHQ activities is contained in the closing chapter: "The surveillance effort between the war in Afghanistan and the "war" at home were now seamlessly connected. The RAF had purchased two Norman Islanders which were equipped with sigint suits. Based at RAF Northholt they are used as covert surveillance by MI5. In early 2007 they were used to support West Midlands police when tracking terrorist suspects. The aircraft fly at fairly high altitude and have been seen loitering over the East End of London for long periods....

Another example cited in the book concerns attempts to place monitoring equipment in shipping containers that were destined to carried back to the Chinese heartlands.

Of course it is in the nature of the subject that one cannot tell truth from myth from disinformation from economies of truth. None the less this is a well written book that set one thinking about modern methods of intelligence gathering and clearly demonstrates the impact that radio intercept has on modern life.

Stewart/G3YSX

A MILESTONE - The CARC 50th Anniversary Club Dinner

This year’s annual club dinner held on Saturday 5th June was a special event in the Club’s history - commemorating the 50th Anniversary of the Crawley Amateur Radio Club’s inauguration. The venue was the Heathy Farm Restaurant on the Balcombe Road at Worth.

Now clubs come and go, and it is quite special when a club can survive - and thrive - that long, amateur radio itself having changed out of all recognition during the past half century. Witness the sophistication of present day equipment, the convergence of computer and radio technologies, the small size of most modern rigs compared with the boat-anchors of yesteryear; the emergence of new technologies -D-Star and SDR to cite two examples of many, not forgetting the commercialisation of what had once been a build-it-yourself hobby. After all, the change and improvements in technology are part of the fascination of radio communications – it wouldn’t have much appeal if there were no improvements in performance and no new modes. And the older ones among us have witnessed these changes.

So, back to the Dinner. Come the evening we had a good turnout with over thirty members and their partners. Because of the numbers attending, Heathy Farm had to accommodate us in two rooms, but this worked out quite well as both were adjoining and it was relatively open plan with no intervening door so their was little sense of being separated, and after the excellent meal everyone was able to inter-mingle quite happily.

The two longest serving members of the Club present were our President Derek Atter G3GRO, and Mike Underhill G3LHZ, both CARC members since the early 1960’s, and we were also pleased to welcome several new club members.

Crawley Amateur Radio Club together with Reigate Amateur Transmitting Society was joint winner of the open section of the 2009 VHF Field Day, and the evening culminated in the presentation to the membership of the RSGB Surrey Trophy. The Trophy had earlier been formally awarded by RSGB President Dave Wilson M0OBW, to the RATS chairman and co-team member Peter Tribe G0VVE, who accepted on behalf of both clubs. To close the formal part of the evening Mike Underhill G3LHZ gave a short address outlining the history of the club.

According to comments this was a very pleasant evening enjoyed by all who attended. We are now taking bookings for the 75th.

John G3VLH

Another Successful Foundation Course

We ran yet another successful Foundation course over the weekend 25th/26th September, with seven students attending and three of the new licence holders joining CARC. Ages ranged from 11 years to the quite mature! All the tutorials went well and for the HF Practical I even managed to get the shack station on the air with the help of Rob's recently posted instructions.

Many thanks to Ted MacDonald (G4TTY) for helping with the training and conducting Morse tests, also Dick Lupton (M0RXZ) for his contribution as Exam Invigilator.



There is also a growing interest in an Intermediate Course, particularly after this recent Foundation. However to allow students to re-group, the previous starting date has now been put back until mid-November."



73 Malcolm
(G3NZP)

Stop Press - VHF NFD

Hi All,
Herewith a "Stop Press" posting for the CARC blog :

< Stop Press : The adjudicated results for The July 2010 VHF Contest
have just been posted on theRSGB VHF contest site (www.rsgbcc.org)
- - - The joint Crawley- Reigate team under the callsign G5LK/P have
achieved yet another excellent result in the 2010 VHF NFD contest
coming in overall second place in the UK open section being just
pipped by the very strong G3VHF/P Colchester ARC team who until last
year had been overall winners for the past 5 years until being
displaced from first place in 2009 by the CARC/RATS entry.
The G5LK/P team gained overall first on the very hotly contested
144Mhz band and second place on 432Mhz and third place this year on
1296Mhz after achieving first place in 2009. The results on 70Mhz and
50Mhz were a little disapointing by comparison at 7th place and 12th
place respectively, However this is a good overall result -
congratulations to all the team.
[A more comprehensive report with photographs will follow later]
de G3GRO >

More information is available at

http://www.rsgbcc.org/vhf/results/10/VHFNFD.html

The August Meeting QRSS by Hans Summers G0UPL

On August 25th we were delighted to welcome back Hans Summers G0UPL. Hans gave CARC an inspirational talk on homebrew back in 2006, and before that time and since, has been putting in a lot of hours on QRSS.



He had given a presentation to the Four Days in May symposium at Dayton earlier this year so when Richard G4ANN, Stewart G3YSX, myself and others from Crawley were sitting in the FDIM audience it was a natural to invite him back to Crawley to reprise his talk. Now it should be mentioned that Hans was inducted into the QRP ARCI Hall of Fame at Dayton last year, and so it was quite an honour to welcome him back.

QRSS - What it is and what it does
So what is QRSS? Using extremely slow CW, it is possible to use a computer sound card and special software to extract CW characters from below the audible noise floor of a receiver. Morse code element lengths of 10 to 30 seconds per dot are commonly used.

QRSS enables operators to extend the range of very low power HF communications using simple low-cost home-brewed gear. This is a large part of the attraction of QRSS, and some amateurs who have got into this mode now use nothing else.

The global reach of QRSS is of course part of its fascination. This coupled with the
ability to use simple low cost home built equipment.

• Information theory (Shannon) says that the slower you send, the less bandwidth you need.
• A narrower bandwidth receiver filter means less noise gets through along with the wanted signal, leading to higher Signal to Noise ratio.
• SSB (2.4 KHz) is better than AM.
• CW is better than SSB.
• Very slow CW (QRSS) is better still!

Hans shows that the theoretical improvement in SNR is then:

• 12 wpm CW, occupying 10Hz: 0dB
• 8 wpm CW, occupies 6.67Hz: +1.8dB
• 4 wpm CW, occupies 3.33Hz: +4.8dB
• QRSS 1s/dot, occupies 1Hz: +10dB
• QRSS 3s/dot, occupies 0.33Hz: +14.8dB
• QRSS 10s/dot, occupies 0.1Hz: +20dB – that's 4 S-points relative to 12wpm Morse!

In other words: 1W of QRSS can communicate as well as 100W of 12wpm CW, or 24kW of SSB!

Some History
In 1964 RCA developed what was in effect the first emergency system using narrow band CW. Operating on around 15 MHz and with a transmitter power of 100mW to a half-wave bent dipole, the equipment was battery powered. The transmitter was crystal controlled, using a special crystal optimized for 37C and placed under the operator's armpit to maintain temperature stability! The transmit frequency swept over 20Hz in 20 seconds at a rate of 3 bits per minute. With a receiver bandwidth of 0.75Hz reliable communications was possible over 2,000 miles in daytime.

Current Design Trends
What therefore are the design parameters for today’s QRSS receiver and transmitter? The major change is in how the very narrow receive selectivity is obtained, from the use of a computer sound card rather than a crystal filter. Quite a modest PC or laptop running FFT software analyses your receiver audio via the sound card input. For this to happen you will also need suitable software, of which there are various programs available for free download, including Argo, Spectran, Spectogram, and Spectrum Lab; Argo being the ideal beginners choice.

And once you start, QRSS is addictive and it's great fun. It’s also great area for home brewing, with lots to learn about propagation, new criteria becoming important e.g. frequency stability to keep within the extremely narrow bandwidth, and frequency measurement.

Of the groups available on the web Knights QRSS group is particularly active.

A 30m QRSS Transmitter Kit has been produced by Steve G0XAR and Hans G0UPL.



Earlier this year they produced 100 kits which Hans took to Dayton FDIM.



The kits were sold out in four hours following his FDIM QRSS presentation on Thursday 13-May. It is now available again at a cost of £10.00.

Where possible the preferred method of construction is into an Ozon mint tin. These mints are available at many newsagents here in the UK. One target is a complete 20m station in a box, not just a transceiver.



Therefore the tin should contain the battery pack, Morse key, headphones and even
antenna wire!



QRSS Receiver in an O\ZON Mint Tin

The components for this project were all chosen for small size and low current consumption. Hans carried out some on-air tests during QSO's on 80m CW - the other
op re-tuned for 20m and listened for the rig, but nothing was heard. Some more work
is needed on this project.

Beaconing and Your License
Running mWatts it is tempting to run in beacon mode, although current legislation states that beacons must not be unattended. However Knights QRSS group have coined the term MEPT – Manned Experimental Propagation Transmitter - and are lobbying for “MEPT”'s to be legalized within the license conditions. In Hans opinion
these tiny powers don’t really get noticed much!

30M QRSS Beacon
Hans describes this as “A borderline insane” 30m QRSS beacon project, completely independent of computer control and containing NO microprocessors! The beacon contains an 8K EEPROM (28C64 chip) of which only 1K is used. It is programmed by hand from front panel switches. The controller is capable of the following modes:

• 12 WPM ordinary CW
• QRSS3 (CW with 3 second dot length)
• QRSS10 (CW with 10 second dot length)
• DFCW3 (dual frequency CW with 3 second dot length)
• DFCW10 (dual frequency CW with 10 second dot length
• A type of slow-Hell Schreiber

These very narrow bandwidth modes are decoded using a Fast Fourier Transform (FFT) program running on a PC. For more details of these modes visit ON7YD's Extreme narrow bandwidth techniques page.

This project was/is a long series of modifications, operation periods, reports, and endless expenditure of frustration, patience and sometimes jubilation. Eventually Hans received reception reports from all around Western and Northern Europe.

These reports included Mike ZL4OL, Tjærand LA9BEA, David VK6DI, Heinz OE5EEP, Peter PA1SDB, Johan SM6LKM, Vic G3GKI, Larry WB3ANQ, Chris DL6JAN, Erik ON4LP, LA5VNA and others.

In pursuit of his final goals Hans casts his net wide and there were a numerous sub-projects included in his presentation, such as battery cells to power these small rigs.



Baked Bean cans, Orange juice bottles and Bleach. 4 Cells make a
battery.

This was a subject in itself, and explored the use of baked bean tins, lemons, orange juice bottles and containers of Azda bleach.

The use of LED s as varicap diodes was looked at in some detail, and of the built projects the small receivers and beacon transmitters, and the beacon controller were discussed in some detail. An L-Match ATU was another project in the G0UPL portfolio.



The G0UPL L-Match ATU

In addition to his home QTH Hans also took kit and operated from Granada in the Caribbean and Southern Turkey where he also received some long-range reception reports.

Within the confines of CARC On Line’s Blog pages it really isn’t possible to do full justice to the scope of Hans’ talk, and for that we strongly recommend visiting his excellent website at www.hanssummers.com

John Longhurst, G3VLH