Congratulations to HARC

Tony Wadsworth , G3NPF has recently posted to Horsham Club (HARC) membership that the Club have again been awarded the David Hill (G4IQM) Annual Trophy for the 3rd time for being the leading group in the 2010 Top Band Club Calls Contest run in November earlier this year. This is a hotly contested event and I CARC wishes to warmly congratulate HARC for achieving their consistent success in this event. This is all the more poignant for CARC as David was a past Chairman of CARC and of the RSGB HF Contest Committee.

73, Derek G3GRO

Christmas Greetings

To All Crawley Club Members and Their Families
We Wish You a Merry Christmas and a Happy 2011

Derek Atter, G3GRO, Hon President CARC

Graffiti

Spotted by Andy G4JNT near a local marine college:

http://picasaweb.google.com/andy.g4jnt/CountryParkRiverHamble#5553550081843582498

Gears

Not amateur radio, but none the less likely to be of interest.

First some square gears:

http://www.flixxy.com/gears.htm

and now to really freak you out some organic gears

http://www.youtube.com/watch?v=3LdlSAN1yks

Thanks to Adrian G3VJM for pointing these out.

- Stewart

The CARC Buildathon Coaxial Loop - Update

I was pleased to receive the following note recently from Ted G4TTY

“Peter

Over our snow enforced holiday, I have been catching up with QSL cards.

The following are the countries that I contacted using that Loop we all made at the Club. I had it fixed to the rafters in the loft.

TED G4TTY

July 08 to October 08, 7MHz”

Call	Watts
EI7CC	30
EA1BRB	30
F5HPY	50
SP6EBK	50
PA0RTW	45
PA1MAK	45
F5OZC	50
M3MUB	5
DP7X	50
F5TO	25
F51AE	40
IN3/1K1 ZJB	10
DL5RDT	5
HB9ANE	30
DL50DRAX	30
DK2NV	25
PA1MAX	4
DK3WM/P	10
DL9TX/QRP	10
DL6LSW	30
HB9ANE	30
LA5UJ	50
DJ2CV	50
DF5VR	50
DA0T	25

Many thanks for your interesting note, Ted. It’s always good to get feedback on the usefulness of this very simple, almost zero cost antenna. For those who may have missed the original CARC Buildathon articles, here are the links.

http://carconline.blogspot.com/2009/01/tuneable-magnetic-loop-antenna-for-7mhz.html

http://carconline.blogspot.com/2009/01/coaxial-cable-40m-tunable-magnetic-loop.html

http://carconline.blogspot.com/2008/12/tuning-knob-control-for-carc-buildathon.html

73

Peter G4FYY

Snow Club Meeting tonight

I have spoken to a few other committee member and in view of the weather, the club meeting tonight will be cancelled.

Instead of meeting in person a group of us propose to gather on GB3WS at 8pm for a short net.

We will make a decision about the fish and chip supper tomorrow morning.

Stewart/G3YSX

RSGB launches major Amateur Radio survey

I am forwarding the following announcement to members of CARC:

On the 1 October at the National Hamfest Newark, the RSGB launched a major survey of the UK Amateur Radio, SWLs and those interested in other aspects of radio communication.  We want to know how you pursue your hobby, your interests from QRP to "Moon Bounce" what bands you work on, are you a contester? All the information that is necessary to see which way the hobby is moving in the 21st Century.  The survey is web based, takes between 10-30 minutes to complete and it is open to all, RSGB members, lapsed members, non-members, Short Wave Listeners, etc.   At the end of the first week over a thousand Radio Amateurs across the UK had completed the survey, this is very encouraging.  You have plenty of time to go on line at (http://www.rsgb.org/survey/) to complete the survey as it runs until the 31 December.  Early completion would be appreciated because we want to start the data collection and keep you posted on the findings as the information comes in.

Although the survey is designed for the individual Radio Amateur a second group of questions, designed for local club participation, so that club members can discuss at length their collective views has been prepared and is available on the same link at the Questionnaire.

The questionnaire is open to all, and please remember that normally only a relatively few people respond so those that respond have a relatively large input to the information gathering process.

If you have any views on the club survey, then please provide that feedback to a member of the CARC committee.

Stewart/G3YSX

RF Perf Board

There has been a bit of chat on the lists recently about some RF prototyping board available as item 170571350963 from the well known action site.

It is a square matrix of copper squares one side each with a drilled hole in the center, and a solid copper plane (apart from the holes :) ) on the other side.

I have never got on to well with this sort of "dot matrix" board, but I would be interested in knowing what others think.

It occurs to me that one should be able to put together a similarly useful prototyping arrangement by laminating some Veroboard with some single sided PCB and drilling through holes where required.

Stewart/G3YSX

A Cool Site - well for an Electronics Geek

This site (http://www.electricstuff.co.uk/)was originally brought to my notice because of its hollow state (valve/tube) content, but it's worth scrolling down past the Tesla coils to miscellaneous section.

Stewart/G3YSX.

Various Active Antennas

In response to a request for help with active antennas posted on the GQRP list. Chris Trask N7ZWY / WDX3HLB posted the following interesting response:

"Here is a design for an active short monopole:

http://www.home.earthlink.net/~christrask/Paper003.html
http://www.home.earthlink.net/~christrask/Paper007.html
http://www.home.earthlink.net/~christrask/Paper005.html

a remotely tuned ferrite rod:

http://www.home.earthlink.net/~christrask/Paper006.html

an active wideband dipole:

http://www.home.earthlink.net/~christrask/Paper021.html

a remotely tuned loop:

http://www.home.earthlink.net/~christrask/Paper011.html

and an indoor loop:

http://www.home.earthlink.net/~christrask/Paper018.html

I'm working on an indoor loop that uses a dual 365-pf variable rather than varactors.  It will have higher Q and zero overload problems."

So a few projects to keep people busy over Christmas and SWL QRV.

Stewart/G3YSX

73 Magazine Online

73 Magazine fans, for those that did not know, the archive is on line at http://www.hamcall.net/73

Note that for some reason they did omit 1971.

A Simple Signal Canceller For 136Khz To Combat Loran or Other Noise Sources

Derek Atter G3GRO

This is a copy of an article that Derek published in the CARC Newsletter some years ago. It is republished here in response to requests for a more accessible copy of the article.

Prior to building this simple signal canceller, some experiments were carried out using an MFJ 1025 Signal Canceller Unit (see footnote) to cancel pulse sidebands from the Loran navigation system which spread into the 136 Khz LF band and often masks weak stations. By feeding signals from the main inverted "L" antenna together with the signals from a large vertical receiving loop ( 3 turns, approx 20ft by 20ft) into a twin channel up-converter with 10Mhz IF outputs and then into the MFJ1025, which is only designed to cover from 1.5Mhz to 30 Mhz, the Loran pulse sidebands can be completely nulled out leaving the DX stations in the clear and making a major improvement to my 136Khz receive capability not to mention the relief from not having to listen through the constant clatter of the Loran. I have also found the canceller system equally effective in dealing with a local noise source which has recently appeared just at dusk and which sounds as if it may be a defective sodium street light. As an experiment I have in fact built two loops at right angles, the plane of one loop running SW-NE favouring the Loran and the second running SE-NW for some experiments in comparing signals with different loop orientation. It should be noted that it is not practical at LF as it is at HF to produce a cardioid pattern using two nominally omni-directional wire antennas because at LF, the spacing would be small in terms of wavelength and hence there would be insufficient phase change with azimuth angle. It is the fact that there is a 180 degree phase change between signals arriving from opposite sides of the null at right angles to the plane of the loop that makes it possible to generate a cardioid pattern when signals are combined in the right proportions with those derived from an omni. The signal canceller based on the MFJ1025 has proved to be very flexible and effective but it is fairly complicated and having established what could be achieved in practice, I have now built a very simple cancellation system operating directly at 136Khz principally aimed at knocking out splatter from the Loran but also proving the capability of dealing with other sources of interference providing that they do not lie close to the bearing of the wanted signal! The canceller now feeds straight into the FT990 transceiver at 136Khz rather than through an up-converter.

The Canceller - A Poor Man's MFJ !
The basic 136 Khz canceller has only 5 passive components ( See Figure1 below). The signal from the omni-directional wire antenna feeds an adjustable phase shifter with the output from the phase shifter being simply fed directly in parallel with the input from the loop antenna via an isolating variable resistor RV2 which controls the amount of omni-derived signal being combined with that from the loop. A change-over switch S1 at the input to the phase shifter allows a 180 degree phase shift to be added to that of the phase shifter. Capacitor C1 and variable resistor RV1 together with the tri-filar wound transformer form a variable phase-shifter with a range of approximately 180 degrees and reasonably constant amplitude over its control range. The variable phase control RV1 does not quite reach 0 degrees at one end of its travel and so switch S2 is provided which allows a fixed selection of the 0 degree position. This simple signal combiner arrangement is based on the premise that the signal from the inverted "L" will normally be much larger than that from the loop and thus allows the omni signal to be fed simply in parallel with the loop output from the phase-shifter via a reasonably high value of resistance in RV2. without adversely affecting the loop signal level. Adjusting the RV2 in conjunction with phase control RV1 allows the unwanted signal to be nulled out. In my case, the combined output of the loop and omni antennas from the canceller is then fed via a bandpass filter and 20dB amplifier to the receiver input of the FT990. It is also useful to be able to switch off the omni or loop inputs individually via S3/S4

The RX Preamplifier
Most general coverage receivers tend to be somewhat short of gain at LF and although the signal from the main LF antenna was adequate, I found that even a relatively large loop needed some additional gain in order to provide sufficient signal level from the Loran to allow cancellation to be effective. With some receivers, the preamp may not be necessary but any preamplifier should have a low intrinsic noise figure to avoid adding additional unwanted thermal noise to the omni signal and hence degrade the overall noise performance. The preamplifier I have been using has two stages of amplification and is preceded by a bandpass filter. The bandwidth of the input bandpass filter is about 3.5 Khz. Switch S5a/S5b is an optional facility which allows the bandpass filter to be replaced by a low-pass filter with a 3dB cut-off frequency of around 180 Khz so that the preamp can be used from a few Khz up to above 200Khz for general LF use. The preamp uses two MAR3 Minicircuits "Modamps" in series which each have a gain of 12dB and -1dB saturation point of +10dBm plus a good noise figure. They also have a nominal input impedance of 50 ohms. The choice of two MAR3 gain-blocks rather than a single MAR6 with a similar total gain, was dictated by the better signal handling capability of the MAR3. I have in practice found the signal handling of the latter very good even with a wide open front-end. The -3dB bandwidth of the input bandpass filter can be adjusted to approximately 3.5 Khz by means of the small top coupling trimmer capacitor VC1 between coil L1 and L2 to give a flat top response or slightly over-coupled double hump response after first peaking the cores of L1/L2. with loose coupling. Diodes D1/D2 at the input protect against unwanted TX power.

Performance
The nulling performance of the simplified system appears to be similar to that of the more complicated earlier version using the MFJ1025. The Loran interference produces the equivalent of around 15 microvolts (+24dbuV) without the nulling system in operation giving an S meter reading of S4/S5 on the FT990. This can be nulled quite smoothly down to below the prevailing general local noise which during the day averages at around S1on the S meter (around about 1microvolt) or less with of course the occasional kicks and clicks etc. on the S meter from time to time. A strong carrier for example ( eg. DCF39, the German RTTY station on 138.8 Khz) can be nulled by typically 30 dB but the phase and amplitude controls then become quite critical to achieve that depth of null. If one wishes to use canceller on very strong carriers etc. it may be beneficial to split the amplitude adjustment RV2 into separate coarse and fine controls. Avoid wire-wound potentiometers. Some random variability has been observed in the depth of deep nulls during periods of high winds which is thought to be due to phase changes arising from the slight de-tuning effects as the wire antenna swings in the wind but does not have any significant practical effect the cancellation of Loran etc. With the canceller system in use I have been able in recent weeks to copy weakish DL/HB9 stations etc. with relative ease whereas without it, I would not even have detected the signal or have extreme difficulty in copying. Fortunately, from my location in Sussex (IO91VC), there is currently no DX activity on the same heading as the Loran station which of course would also be nulled out!

The Antennas
The main transmitting antenna being used at the moment to provide the omni-directional input to the canceller system is a base-loaded inverted "L" with the vertical section of around 36ft and a 3-wire top loading capacitance of 3 parallel wires each of 150ft strung between spreaders at each end. The above antenna feeds the canceller system via the transmit-receive switching relay.

The 20ft square loop antenna used to cancel Loran is strung between trees about 25 feet beyond the end of the main transmitting antenna and uses reasonably thick (1.5mm2) stranded insulated wire to keep the RF losses low. The individual turns of the loop are just bunched together and suspended at each corner via an insulator. The loop is resonated by two capacitors in series across the loop mounted at the centre of the lower leg providing capacitive tap matching to the output coax. The "bottom" capacitor is 47N in parallel with10N across the 50 Ohm feeder; the "top" capacitor has a value of 7.65N made up of several individual capacitors in parallel one of which is a 500pf compression trimmer. The capacitors are mounted in one of the small sealed kitchen food storage containers. The loop may be tuned to resonate at 137Khz by injecting a signal generator into the 50ohm output port and connecting an oscilloscope or RF millivoltmeter across the loop via a high impedance probe and adjusting the capacitance for resonance.

I have added a slight complication in my version of the loop interface box to include a small 12v relay and RF choke to allow DC to be fed down the coax cable to the loop so that the second loop running at right-angles can be remotely selected from the shack in the house some 150ft away.

My experience with smaller multi-turn loops of around 1 metre square has been somewhat disappointing in receiving DX stations by comparison with the main inverted "L" antenna nor did I seem able to obtain sufficient signal from the Loran sidebands to adequately cancel the Loran hence my use of a larger loop . However this may have been due to shadowing from the large wire transmitting antenna and if it is not practical to put up a larger loop then it may me worth investigating a smaller multi-turn loop in other sites.

G3GRO 60 years RSGB

Announced in RadCom this month, Derek, G3GRO has been a member of RSGB for 60 year.

Stewart/G3YSX

RSGB Abandons 2010 Board Election

A few days ago, the RSGB made the following announcement:

"Governance of the RSGB is regulated by the Memorandum and Articles of Association (M&A) of the Society, a copy of which may be found on the Members’ only section of the website.

"An irregularity has been identified in the nomination of the two candidates to stand for election as nationally elected members of the Board. Unfortunately, it was not noticed until after RadCom had gone to press that both candidates shared two nominators. This is not in accordance with the M&A and therefore the candidates were not properly nominated.

"The Board has considered its options under the M&A and has determined that the only course of action open to it is to declare the election for nationally elected members of the Board invalid. Given other requirements of the M&A, the Board will now co‐opt both candidates as Board members for a twelve month period until the next election (late 2011) when the candidates may stand for election again.

"The Society very much regrets this error, but believes that the best interests of the membership are served by acting as set out above."

This simple apology, without a description of how the error occurred or what steps have been taken to ensure that it does not recur, belittles a serious breach in the process by which members have their only input on important aspects of the operation of the society.

The structure of the RSGB is that the members elect the Board. The board directly appoint the chairman of committees, and the chairman of the committees appoint the committee members and define the mode of operation of the committee. The operation of these committees has a major impact on the amateur radio in the United Kingdom.

A number of us in CARC already have grave concerns at the lack of accountability, lack of transparency, lack of openness, and unwillingness to take member input into their decision making, of RSGB committees. This is particularly the case with the ETCC which directs Ofcom in the allocation of spectrum to major amateur radio systems such as repeaters.

Thus the RSGB Board has this year denied the membership of the society any input into the only part of the process that it can use to affect decisions that have major impact on the regulation and operation of amateur radio in the United Kingdom.

Given that in some aspects of its the work the RSGB acts as an agent for the elected UK government, the absence of a proper Board Election in 2010 is, in my view, an affront to democracy and therefore unacceptable behavior by the body that represents amateur radio in the United Kingdom.

Stewart/G3YSX

Questions to Prospective RSGB Board Members

To

Phillip Brooks, G4NZQ
Charlie Morrison, GI4FUE

Dear Sirs,

I am writing on behalf of the Crawley Amateur Radio Club. You are a candidates for election to the RSGB Board. We have read your statement in RadCom, but we have a number of questions that we wish to put to you to factor into our decision making before voting in the Board Election.

To make this an open process I have posted the questions on the CARC Blog (carconline.blogspot.com), and have requested that Southgate ARC (http://www.southgatearc.org/) post them on their Newswire service. We would request that you copy your answers to those two web services, or that you request that I do so on your behalf.

1) Many elements of the RSGB decision making process take place behind closed doors with little effort to consult with members before a final decision is made. In this modern, Internet connected era, there are many ways to solicit wider input from the community. If (re)elected what steps will you take to ensure that the RSGB Board gathers wider input as part of its decision making process?

2) The sub-committees of Board, for example the ETCC is composed primarily of unelected members. What steps will you take to ensure that the membership of sub-committees is more representative of RSGB membership, that they are accountable to the membership for their decisions and the that decision making process is transparent and includes an appeal mechanism?

3) The RSGB recently increased its membership fees at a time when members are under considerable financial stress. What measures do you feel the RSGB should take to ensure that it does not place additional financial burdens on its membership during the current financial crisis?

Stewart Bryant
Chairman Crawley ARC

Simple LCR Bridges

I have mentioned to a few people that I built the LMS Impedance Bridge published in both QEX and QST by Dr George R. Steber, WB9LVI. The design can be found at http://wb6dhw.com/RLC_Meter/N%20LMS%20Impedance%20Bridge.pdf . Indeed I thought that I had written it up for the CARC blog, but when I went to look for it I remembered that I had delayed writing it up because I got bogged down trying to compare the results of a number of LCR meters at the G3YSX QTH.

The thing that brought this to the top of my mind, was the following design by Rik Strobbe ON7YD http://www.rcl-meter.strobbe.eu/index.html which shows an even simpler version using just two resistors and two capacitors. Rik, ON7YDD is well know for his excellent technical work on LF communications. The only downside with Rik's design, in common with all of these instruments, is that it requires an audio card with line in (i.e. with stereo in), and unfortunately these are only to be found on desktop machines or on the more expensive USB sound "cards".

I have not tried the ON7YD version of the LCR bridge, though I expect that I will, if anyone does build one I would be interested in reports on its performance.

- Stewart/G3YSX

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

Crawley Microwave Round Table Program Sunday 12th September 2010

This venue has a reputation of having a very friendly atmosphere - come along and support the construction contest and hear the talks.

10:00 Venue Opens
The pre-lunch program will open with the usual table-top sale of useful bits and pieces plus general natter session giving a chance to meet up with old friends.

In parallel we will be as usual running the UK Microwave Group annual construction contest for the G3VVB trophy. Participants are invited to bring along items of home constructed equipment and enter the contest. Entries do not necessarily need to have been constructed during the past year. Last year's winner was Mike G3LYP – this year it could be you that carries away the trophy!

12:00 Construction contest judging commences.

13:00 Lunch. (rolls, sandwiches etc. and tea/coffee will be available at the tea bar)

14:00 Opening address by Derek G3GRO and the results of the construction contest

14:15 What to do with a big dish ? Mike Willis G0MJW

15:00 Getting the most from your G3DDK LNA – Sam Jewell G4DDK

15:45 Break. (tea and coffee available)

16:00 Applications for weak signal modes – Brian Coleman G4NNS

16:30 End of meeting

The Mystery of the Phantom Whistling Kettle - an Unusual Case of RFI!

One night during recent testing of the revised earthing arrangement of my HF Windom antenna I became aware that I had signs of RF feedback on 7Mhz SSB when running QRO especially with the audio processing switched on in my FT1000MP – a sure sign that all is not well with the earth routing in my newly relocated shack downstairs in the conservatory . I had also heard a few occasional thuds from the loudspeakers of the hi-fi system.

I then became aware that I could hear the electric kettle whistling in the kitchen which has a rather unusual mournful sound as the whistling dies away after the appliance switches off after reaching boiling point. This puzzled me because that apart from myself, I thought that the house was empty.

So I went into the kitchen to investigate thinking perhaps I had an un-announced visitor but the kitchen was empty and what is more,the water in the kettle was cold so it could not have boiled to create the whistle! It was only at this point that I realised that the whistle on this new Morphy-Richards kettle was not in fact driven by steam but was electronic in origin and had a switch underneath to turn the noise on or off! A couple of bursts of QRO on 7Mhz again produced the same mournful wailing again confirming that I had clearly got quite a bit of stray RF getting into the house wiring since the kettle 13A plug in the kitchen was at least 35ft away from the earthing point of the HF rig and Expert 1K-FA linear amp.

Helped by Peter G4FYY, some general re-routing and shortening of the various earth leads ensued and separation of the earth route from the ground point of the in-line choke balun in the feeder to the Windom antenna to the copper ground stake. This seems to have cured the earth problem and now when I hear the kettle whistle I know that a cup of tea is really on its way !

73, de Derek G3GRO

Intermediate Course being Planned

Subject to sufficient take up, there are plans to run a 10 week Intermediate Course commencing Thursday September 30th, 19.00 to 21.00 each week. The contact address to register for the course is training@carc.org.uk.

Foundation Course 25th and 26th September

Malcolm, G3NZP has now confirmed that CARC have sufficient interest to run a Foundation Course on 25th/26th September and there will probably be room for a couple more candidates. The closing date is Friday September 10th, so if you, or anyone that you know are interested in taking the foundation course/exam, please contact CARC using the club training email address (training@carc.org.uk).

What is it?

This was bought at boot fair the seller knew nothing about it so nothing known about it's origin. It seems to have 2 electrical connectors at the top with wires hanging down to make contact with a sample or something and in the centre there is a probe which can be screwed in and out.




Richard G4ANN

Bletchley Park WWII archive to go online

Millions of documents stored at the World War II code-breaking centre, Bletchley Park, are set to be digitised and made available online.

Electronics company Hewlett-Packard has donated a number of scanners to the centre in Milton Keynes so volunteers can begin the ground-breaking task.

For more info click here

Or here

10 Metres Opens Up For Early Sporadic-E Openings

It would be worth keeping an eye open on the 28MHz band over the next few days. The band was open for some very strong sporadic-E contacts across Eastern Europe as far as OK & SP and down into southern Italy as well as DL and OZ plus south westwards to EA yesterday (13 May) and also today (Friday 14th) from noon until late afternoon.

One notable SSB QSO was with Raphael IM/P- IK0FMB (what a callsign!!) on the little island of Antioco, 20K West of Sardia with an S9+ signal with 400W to a 2-ele home made beam who gave me a 5&7 report with 400W from my windoim antenna.

There were quite a few low power beacons to be heard including IZ8DXB/B in JN70L as far south as Naples and EA4Q in Spain. Stations on 28 MHz were reporting that 6M was also open although when I listened a bit later I heard nothing on my windom.

Lets hope that this early opening is a foretaste of good DX conditions this summer on the HF Bands as the sunspot cycle progresses.

73, de Derek G3GRO

Dayton 2010 day 1

This is the first of a series of mini posts describing the trip to the 2010 Dayton Hamvention. G3VLH, G4ANN, G3LHZ, M0ZAF and myself (G3YSX) traveled out to DAY via Charlotte yesterday. Looking at the various blogs, we did better than many other European hams who tried to go out yesterday, but none the less it was a long haul. We got here, but it seems that those that tried to travel out via Spain found that flight after flight was canceled.

In our case the flight was delayed from 0940 to 1140 due the late arrival of the inbound aircraft, which was in turn caused by an extended flight to dodge the ash. Our flight time increased from 9 hours to 11 hours due to the need to fly north of the volcano to avoid the ash.



From the aircraft we could see the volcano off the port side of the aircraft.

We finally landed at 16.56, 3 hours 20mins later than planned. We were then moved on to the (late) 19.49 flight to DAY in a process that was very smooth by US Airways. We then arrived at Dayton field just as a thunderstorm settled in. A bit of bumpy air and a short hold gave the pilot an opportunity for a slightly expedited landing just as the storm moved to the south of the field.

Getting the hire car was smooth, but navigating the extensive roadworks put our GPS sat nav into a routing loop. We told it to use minor roads only, which did the trick, and finally got to the hotel at 23.30. For me this was a total journey time of 21.5 hours.

Stewart/G3YSX

MTI ATU2000 / STR400

Richard, G4ANN, is looking for information on an Automatic ATU that he is hoping to repair and use on HF. The label says that it is made by (or at least Marketed by) Marine Technology International Ltd. It has markings STR400 and ATU2000 on the cover.

Outside and internal pictures are shown below.

If anyone has any information on this ATU, particularly a circuit diagram and/or a manual of some sort, please can you email (stewart at g3ysx.org.uk), or add a comment on the blog.

Thanks in advance for any help

Stewart/G3YSX

VHF NFD. The Presentation.

They say a picture paints a thousand words. Well here are two pictures that are the result of literally thousands of man hours over several years.

Peter G0VVE and Andy G7FWE clearly capture the mood at the award ceremony held before the RSGB AGM in Bedford this morning.







See you all on the hill at 15:00L on Friday 2nd July.
Or on the air from 14:00Z on Saturday 3rd July.

CARC Spring Surplus Equipment Sale

31st March 2010

Well, we had a reasonable turnout for the Spring Surplus Equipment Sale, and there was quite a wide range of equipment to go under the hammer – signal generators, a nice HP scope, a Dymar 2-tone audio generator, frequency counters, an ERA Morse Reader, a built Howse twin receiver kit, Morse keys, drawers of components, computer stuff and other items too numerous to list. It was also nice to welcome friends from other clubs.

The redoubtable auctioneer and hammer-wielder was Stewart G3YSX, and with Richard G4ANN looking after the financial and admin side of things the evening went without a hitch. And not to forget Ted G4TTY who kept the teas and coffees coming throughout the evening.



Finally, whilst CARC takes as standard a 10 per cent commission on sales we would also like to say a “thank you” to those sellers who donated all the proceeds of their sales to the Club funds – it all helps in these difficult times!

John G3VLH

Mini-Whip with CAT5

I have previously reported on the excellent mini-whip design produced by Roelof Bakker (PA0RDT) (http://carconline.blogspot.com/2009/05/pa0rdt-active-antenna-continued.html).

Recent work on the application of the design to VLF reception has enabled the use of CAT5 (Ethernet) cable in place of a coax feed.



As Roelof said in a note to the RSGB LF reflector : "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."

Referring to work on 9KHz he continues "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."

"I have the parts for an optical link active E-field antenna, as suggested by Stefan. Due to other more pressing matters, I have not yet put them to good use."

It looks therefore as if we can expect further developments of this simple but very effective design.

Joze (S52AB) reports on a CAT5 mini-whip http://s52ab.jalbum.net/mw-test-2/ in which he shows a comparison between reports on a CAT5 fed mini-whip and (presumably) the same mini-whip fed with coax. My visual impression from looking at the received signals is that the CAT5 has a higher loss, although it is not clear at what frequency these measurements were taken. For those interested in LF work, Jose's main site (http://lea.hamradio.si/~s52ab/) is worth looking at.

- Stewart/G3YSX

Triax 2 Lug to 3 Lug Interconnection

At a rally last year I purchased a Keithley 616 Electrometer for a very reasonable price. Unfortunately it had a serious problem as can be seen from carefully looking at the connector in the picture below.



Investigation's on the web through up this Wikipedia article (http://en.wikipedia.org/wiki/BNC_connector) that explained all. As this says:

"Triaxial (http://en.wikipedia.org/wiki/Triaxial_cable) (also known as triax) connectors are a variant on BNC which carry both a signal and guard as well as ground conductor. These are used in sensitive electronic measurement systems, particularly of Keithley manufacture. Early ones were designed with just an extra inner conductor, but later tri-axial connectors also include a three-lug arrangement to rule out an accidental forced mating with a BNC connector. Adaptors exist to allow some interconnection possibilities between tri-ax and BNC connectors."



Unfortunately the plug shown above is very expensive, and even if I had found one I would have then had to find some cable and make the connector, which if making an ordinary BNC up is anything to go by would not have been easy, and the adapters mentioned in the wikipedia article are rarer than hens teeth. I must have searched every new and surplus connector tray at the Friedrichafen show last year, and a good few English rallies and found nothing that would work.

I was at the point of giving up and soldering some wires to the outer contacts (I thought of replacing the connector with a standard BNC, but the internal construction of the Keithley 616 made this a very difficult and hazardous to the instrument) when a friend to whom I am most grateful gave me a triax to BNC adapter.

Unfortunately the adapter was a three lug adapter and as indicated in the wikipedia article it would not mate with the two pin socket (deliberately so). After a lot of measuring and staring at the connectors we concluded that the ONLY difference between the two and three pin varieties was the positioning of the lugs and that whilst not perfect a one lug socket would work well enough (at least compared to the current situation of no mating connector). So out came the Dremel, off came the lug and on went the adapter.





Now in case you are wondering, I do have a reason to want to be able to measure the astonishingly high resistance values that this instrument will measure, but more of that at a later date.

Stewart/G3YSX


Footnote to readers, the reason why CARC shows the full URL hyperlinked to the URL, rather than the more conventional article text to URL linking is to make it easier for our editors to produce the monthly pdf version of the newsletter.

A Loop Experiment

On 15th March I set out for a business meeting in the US and decided that as an experiment I would leave my 40m coax loop that we made at the club connected to my FT817 receiving WSPR. The receiver ran almost continuously for the 14 days that I was away. I say almost continuously, I have a bug in the computer that keeps resetting the the audio port from line-in (which is the audio input port I am using) to mic in (which interestingly still receives the stronger signal due to audio cross talk between the ports) and I needed to remotely log on from time to time to correct this. Because I could not be sure that I would have good internet connectivity whilst I was away I did not attempt to rin the system as a remote transmitter.

Please excuse the mess in the shack, but the loop in use is shown below.



This rather saggy loop is in my loft shack which is constructed with aluminum foil covered plasterboard, although as it is not bonded together I am nit sure what effect it has. It was oriented in a plane exactly East-West.

Over the 14 days on 40m (which is not the most popular WSPR band) I logged 120 unique call signs from 19 countries. To get some assessment of the range groupings I grouped the number of unique contacts into range buckets 1.414 time the previous max range as shown below:

0 to 50Km 2
50 to 121Km 2
121 to 221Km 6
221 to 362Km 9
362 to 562Km 19
562 to 845Km 23
845 to 1245Km 26
1245 to 1811Km 10
1811 to 2611Km 6
3742 to 5342Km 1
5342 to 7605Km 8
7605 to 10805Km 1
10805 to 15330Km 1

The contacts in the range 0 to 500Km were most probably NVIS which is about 38 out of the 120 contacts meaning that about 1/3 were NVIS and 2/3 were contacts that required F layer skip.

I then took a look at number of unique contacts by country, and did a by eye estimate of the baring from my QTH. The results I got were as follows:

Country # Range(Km)
Australia 1 60
Austria 3 111
Belgium 3 102
Brazil 1 220
Denmark 1 47
England 14
Finland 3 45
France 6 160
Germany 35 70 to 110
Italy 9 130
Netherlands 7 76
Norway 1 28
Poland 5 80
Scotland 4 330
Spain 4 190
Sweden 2 47
Ukraine 7 84
USA 3 290

I did not do bearing for UK because they were spread over such a wide arc that I did not feel that the results would contribute much to understand how the antenna behaved.

I then classified the results into front and back (315 deg to 45 deg plus 135 deg to 225 deg) and side (45 deg to 135 deg and 225 deg to 315 deg). The result was that 16 unique reports were made on the front back and 81 off the side. Even if I discount all of the NVIS contacts the majority of contacts were still off the sides. This distribution is heavily skewed by the distribution of round the world stations, but the results would suggest that the small tuned loop probably receives off the side, or omni-directionally rather than off the face which I believe is common wisdom.

Just one final observation I took a look at the powers (in Watts) that various stations that I received were advertising.

Power #
0.05W 1 (Germany)
0.1W 1 (Netherlands)
0.5W 5
1W 12
2W 12
5W 64
10W 8
20W 1 (Italy)
100W 1 (Spain)

I leave you to draw your own conclusions.

It will be interesting to see how this compares to other antennas that I have available and to get a feel for their patterns. I will run some other tests and report what I find.

73

Stewart/G3YSX

DON'T SHOUT BUT "WSPR"

For our talk on 24th February, Walter Blanchard, G3JKV introduced members to the Weak Signal Propagation Reporter system. This uses a clever suite of software which encodes the message to be transmitted, and monitors and decodes other WSPR stations that you can hear, during precisely timed periods with a 2 second cycle time. The monitored signals are decoded and uploaded to a web site which publishes the results in tabular form for further analysing and mapping. In effect it is a world-wide beacon network additional to the traditional beacons (-which are not comprehensibly monitored and tend to have larger power than "weak")

This new digital system is already used by 2 or 3 CARC members (including G3YSX, G4FYY and 2E0MZB) and I hope they will correct and expand on my notes taken during the talk.

In WSPR "weak" means output from the TSCVR of 5 or less Watts and the software can decode signals received with Signal to Noise (S/N) ratio as low as -28dB. This is about 500 times "better" at decoding than the human ear listening to voice on SSB. If like me you find dBs hard to appreciate the WSPR website provides tables of power in Watts and dB equivalents.

The software has been written by Joe Taylor K1JT who is a physics professor at Princeton University, New Jersey, and who with his colleague Russell Hulse won the 1993 Nobel Prize in Physics. Professor Taylor's group continues to explore problems in astrophysics and gravitational physics by means of radio-wavelength studies of pulsars. Among recent highlights are the discovery of many new pulsars, including millisecond and binary pulsars.



In operation the PC generates the encoded signal and switches the radio to transmit at precisely the right time i.e. at the being of each even minute. The PC needs to know precisely the correct time and this is obtained from a time server on the web e.g. dimension 4 at http://www.thinkman.com. The last 6 seconds of the two minute cycle are silent. The PC can run Linux, Windows etc. and a processor speed of at least 1.5GHz is suggested by K1JT, although Walter suggested that 500MHz is satisfactory.

Interconnection
Interconnect between the PC and TSCVR is identical to that used for PSK , RTTY etc.

The connection of the PC serial port and the radios Push to Talk (PTT) is often made to part of the accessory port of the TSCVR. This can include optical isolation and 1A power transistor to handle the current needed by some TSCVRs to switch to Transmit. To carry the audio between the PC sound card and the TSCVR an isolating transformer will prevent the PC's dc voltage on the sound card reaching the TSCVR and vice versa.

There is a wealth of designs and information about PC to TSVCR connection techniques at provided by W5BBR (Google says that there should be a www.w5bbr.com/soundbd.html site, but this did not seem to be up when the editor looked for it. However the material can also be found at http://www.cqham.ru/soundint.htm). The latest version of the software allows interconnection by CAT system, which additionally ensures the frequency set in software matches the TSCVR setting.

The Encoded Signal
The transmitted signal contains information using Frequency Shift keying (FSK) at the low shift value of only 6 Hertz(Hz). The encoded transmission includes; sender's callsign, Tx location and Power level in dB. As the shift is so small it can not be heard by the average listener and the transmitted signal sounds like a continuous 1500 Hz tone. When listening typically there is ?beat? occurring between signals and "woof-woof" sound is heard. The signal is contained in a 200Hz Pass Band.

WSPR signals heard are decoded by the PC and can then be upload to the web at www.wsprnet.org. There are millions of monitored signals on the site and data can be selected for further analysis. To register with the site you need your Maidenhead locator http://www.levinecentral.com/ham/grid_square.php will give latitude and longitude plus Maidenhead locator directly from your callsign using data from QRZ.com.

Having downloaded the WSPR software, to get started try the 30m band as this has many monitored calls listed in the webpage, where distances and azimuth angles are tabulated. Once monitoring is working and your PC is decoding some of the results you can see on the web, you can consider transmitting. Walter drew our attention to the following points

*Correct UTC time (from internet atomic clock)
*Correct dial and transmit frequency remembering that changing freq on rig does not alter the data set on the PC
*Start with Transmit to Receive ratio set at 20%
*Choose the correct frequency band on the menu bar
*Check Rx noise ? needs to be 1dB plus and minus 10 dB tolerance
*Select USB mode
*Use TSCVR with frequency stability within 2Hz at 28MHz or you may need to add the manufacturer's "high stability Oscillator" cost about £50.

What is it good for?
Well there is all the data to analyse in any way you wish. The effectiveness of aerial types, locations, mounting etc. and TSCVR type and power can be monitored by adding switching to change the equipment automatically during the 6 second silent period.

Map of monitored calls



More information
Try www.g4ilo.com/wspr.html This is a clear comprehensive explanation and I suggest is essential reading. Also search for wspr in www.youtube.com to see wspr in pictures!

Further Links

Steve Nichols G0KYA, RSGB Propagation Studies Committee www.qsl.net/g0kya
Walter Blanchard email wb@g3jkv.co.uk

By Ted Aston G7OBF