21 Jun 2011

VLF tests last weekend

Last weekend saw both DK7FC and DF6NM transmitting with <100mW ERP on VLF. Their signals were successfully received by many stations across Europe with best DX for DK7FC/P being 2404km to Iceland. G3ZJO successfully received a DFCW60 message from DK7FC/P.

Both stations described their activity and results in brief reports which you can find via links at https://sites.google.com/site/sub9khz/news .

17 Jun 2011

VLF test Saturday June 18th (DK7FC/P)

Tomorrow morning Stefan DK7FC/P will be testing for the first time in many months using his kite supported VLF antenna. He will be transmitting from mid Germany on 8.9700000kHz (precisely GPS locked) from around 0600z Saturday. His ERP will be in the 50-250mW region.

If you have Spectrum Laboratory (free software) and a suitable E-field probe or loop antenna then this is a great chance to see if you can detect his signals. The last time he tested he was quite a good signal in the UK and was received by several suitably equipped stations.

It is unlikely his signal will be audible, but he should be a clear trace on the SL screen with a suitably narrow bandwidth setting (4.52mHz or less). Frequency accuracy is paramount and you will need a Spectum Lab config file that "locks" onto GBZ or similar to ensure you know precisely where to look. Initial tests will be with a long carrier followed by characters in very slow DFCW or QRSS.

You do NOT need a VLF communications receiver: just a loop or E-field probe and a small audio preamp feeding the sound card of a PC. This is amateur radio "at the edge" in the same way that optical comms is .....but at the other end of the spectrum. Great fun and a nice challenge.

I shall be looking and streaming the received signals to my VLF grabber visible at https://sites.google.com/site/sub9khz/vlf-grabbers/xbm-grabber . It is also possible that G3ZJO will have his (better) VLF grabber on too at http://g3zjo.bplaced.net/ . The RSGB LF-reflector will carry updates in the event of the kite blowing away, going QRT for storms etc..

15 Jun 2011

Scientists predict rare 'hibernation' of sunspots

For years, scientists have been predicting the Sun would by around 2012 move into solar maximum, a period of intense flares and sunspot activity, but lately a curious calm has suggested quite the opposite.

See http://news.yahoo.com/s/afp/20110614/ts_afp/usspacesun

14 Jun 2011

23cm activity contest next Tuesday

Having had some fun in both the 2m and 70cm cumulative contests today and last Tuesday my thoughts are now turning to the next contest which is on 23cm next Tuesday evening. As I don't have any transmit or antennas on that band I shall just listen. Once again I shall have to make a suitable antenna and the most likely will be either a small 4 el beam made from thick wire or a 23cm Moxon 2 element beam which would be about the size of my hand. My 23cm converter has not been used for well over 15 years so that will need to be checked carefully and the LO crystal re-netted.

70cm activity contest - a brilliant /P evening

Stations worked 70cms UKAC 14/6/11
My tiny 4el 70cm yagi made from wood and a couple of coat hangers worked very well this evening netting me 17 QSOs in just over 1 hour of operating with 5W RF from the FT817. Best DX worked was 191km although I heard both GD8EXI and GI6ATZ at much greater distances.

13 Jun 2011

432MHz Contest - June 14th

Tuesday June 14th is the 70cms activity contest from 1900-2100z. I've made a small 4 element yagi for portable use and this mounts on a small 20mm diameter pvc conduit pipe fixed in the window of my car (see image). It is all very lightweight. At the intended portable site I was able to copy the GB3BSC beacon some 200km away today in a trial run. All being well I should be able to work a few stations around the country.

12 Jun 2011

Solar peak THIS year?

The more I look at the data the more convinced I am that we are now reaching (or may have already passed?) the peak of solar cycle 24 much earlier than expected and at a very low peak level. See some interesting data at http://www.solen.info/solar/polarfields/polar.html about solar magnetic field reversals and the latest plot of solar flux and sunspots at http://www.solen.info .  For several months now the general smoothed trend, ignoring blips, is downwards.  We may never again experience the exceptional HF conditions seen at the peak of some sunspot cycles in the last 50 years, at least not in my lifetime.

10 Jun 2011

6m Super DX - use WSPR!

We are now in the season of super-DX Es openings on 6m when the band opens spectacularly across the Atlantic to the USA and the Caribbean as well as northern South America and Africa. WSPR could be a superb tool to help track fleeting openings over these very long paths, but we need more stations on 6m WSPR for this to be possible. Ideally stations need to be operational 24/7 on 6m but as a minimum from around 1100-2400z and located in Europe, the eastern USA, Canada, the Caribbean and northern South America. When not busy on 137kHz I propose to make 6m my WSPR home this summer. If the band opens across the Atlantic then 5W to a small vertical or dipole should be enough to get transatlantic spots. Let's fill the 6m WSPR slot with activity.

6m WSPR today

Good conditions on 50MHz today with WSPR spots from GM4SLV, PA0O and CN8LI when using 5W to the V2000 vertical antenna. The report from John in the Shetlands was -2dB S/N suggesting just a few milliwatts would have been enough. PA0O is interesting as it may not be Es but tropo propagation as the distance is pretty short for Es skip.

8 Jun 2011

137.5kHz WSPR

This evening F8BOJ was testing on 137.5kHz WSPR so I had a go at copying him, although he is around 700km south of me in the null of my fixed loop. G4WGT was copied but so far no sign of F8BOJ. I've also been TXing with 100uW ERP but no reports this evening although GW3UCJ thinks he may be seeing signs of my bursts but too weak to decode.

144MHz Cumulative Contest

Last evening I went out portable with my halo and FT817 to a local (small) hilltop to operate in the RSGB 144MHz cumulative contest. What surprised me was the great amount of activity: the band from 144.17 - 144.36 was packed with SSB stations from all over the UK.  Just over an hour of operation gave me best DX of 203km and 7 stations worked. It was great fun. Next Tuesday evening is the 70cms cumulative contest, so I may well give this a try too from the same spot.

7 Jun 2011

Elector valve radio kit

Not having built valve radios (far too young at 62, HI HI!) my eyes were drawn to the latest offer from Elector magazine for a complete valve radio kit built into a neat wooden case. See https://www.elektor.com/Uploads/2011/6/Valve-Radio-Kit.pdf. This uses a low voltage valve (6J1) in a regenerative design with a transistor audio amp. At around £50 with shipping it is not cheap, but it is a complete kit. For the offer see https://www.elektor.com/extra/valve-radio.1843103.lynkx .

WSPRnet database issues

Several times in recent weeks the WSPR on-line database has been unavailable. Not sure what the problems are. It is a pity as this database of reported WSPR spots is a remarkably useful resource. Maybe it is simply that there are too many users now and the database cannot cope? Like many, I'd like to thank all involved in providing and maintaining this database - thank you guys.

4 Jun 2011

Amateur VLF transmissions this week

G3XIZ as received at 45km 4.6.11
Both Marcus DF6NM and Chris G3XIZ have been active on VLF this last few days. G3XIZ was a good signal on 8.976662kHz with his improved antenna and DF6NM has been copied in Yorkshire by Paul Nicholson. Although QRN can be a problem at this time of the year there is still activity. The screen shot here shows G3XIZ's VLF signal with me today.

2 Jun 2011

6m WSPR

At this time of the year 6m is a great band for sporadic-E DXing with QRP and simple antennas. All of Europe and North Africa is in range with 5W SSB and a dipole, halo or small vertical. At the moment I'm putting my WSPR beacon on 6m whenever I can in the hope of catching some short openings in unusual directions. Best DX reports so far are to/from CN8LI in Morocco at 2113km. With some luck, the band will open up to the USA and Canada soon (multi-hop Es) and I'll get some spots from across the Atlantic on 6m.

26 May 2011

The Elecraft KX3 Ultra-portable multimode QRP rig

There is much excitement about the latest product from Elecraft, the KX3. This was announced at Dayton and it looks like a marvellous addition to the Elecraft range. See http://www.elecraft.com .

The RSGB Luso Tower fiasco

Some time back, the RSGB bought a huge Luso tower - list price £31k, although they got it for less - but are now selling it for £13.5k as they can't get planning permission for it at their new home at Bletchley Park.  What has this sort of monster got to do with amateur radio? What sort of example is our national society giving to newcomers? Pay BIG money for everything to get a BIG mast, BIG yagi, BIG rig and BIG linear?

The RSGB must give more of a lead by showing that this does not have to be a "fat cheque book" hobby and that simple, low cost, equipment can be effective. RadCom does carry some excellent articles, but I fear many newcomers reading the magazine would come away thinking it's an expensive hobby.

25 May 2011

10m Sporadic-E and BIG signals

As an example of just how strong signals can be on 10m with strong Es conditions take the reports this afternoon from DJ0ABR. With 500mW to my halo he was giving me a WSPR report of +7dB S/N. This suggests I'd still be OK with just 500uW from the transmitter. I know others have achieve far better than this but it does remind you that a big sporadic-E "cloud" acts as a very good mirror.











Sepura introduce intrinsically safe TETRA portable

My colleagues at my old company, Sepura, have just released details of their new ATEX intrinsically safe TETRA portable. From my own experience of designing intrinsically safe products (PF2UBIIC, EXPF85) this is a far from easy task, especially today when the tests are even more extreme and challenging. Well done to the team involved.

Intrinsically safe radios are designed to be used in very hazardous locations such as oil refineries or petrochemical plants where the risk of explosion is high. They are designed to be safe even in certain fault conditions.

My first JT65 QSO

Although I've listened/looked at received signals with this mode, this morning I had my first ever JT65 QSO (using QRP of course) with EA1YV on 14.076MHz. I used the JT65-HF package with the simplified interface for HF QSOs. It worked a treat. See http://physics.princeton.edu/pulsar/K1JT/JT65.pdf.

As I've no antenna for 20m I just used my 10m halo tuned via the Elecraft T1 auto-ATU.

24 May 2011

4m transverter - some builder feedback

Just got this very nice email about my 4m transverter:

Hi Roger,
               My name is Mark (mi0bdz) and I was browsing the net for 70mhz projects when I came upon your site. I could hardly believe the simplicity of the little 70mhz  transverter you designed and built. I decided to copy it. I started on Friday afternoon after gathering the bits together and completed it by Saturday evening. I could not have done this without thanking you for sharing the project,  which I class as the best usable project I have come across in many years.
   I have found that by careful selection of the TX transistors and bias resistors that 3 watts is possible. I did have to alter the values of the bias resistors quite a bit, but that is all. Everything else is as your schematic. Thankyou again for a wonderful little project. This is a gem. The sensitivity is also excellent. You were right about packing a lot into a chip indeed. Thanks again Roger.

  Regards
             Mark

23 May 2011

Cycle 24 already peaked?

Check out recent trends - it looks like the present cycle has already passed it's peak. Or is this just a blip?

22 May 2011

6m Es

Well, the 6m sporadic-E season is in full swing again: yesterday loads of Europeans worked with QRP and the vertical and this afternoon being spotted in Spain with WSPR. Initially it's fun working around Europe, but as the season goes on the real excitement is further afield looking for US/Canadian and South American stations on 50MHz. It never fails to amaze me how far one can hear/work on 50MHz with the right conditions. Also, next month should see the return of UK-Japan openings on 6m possibly as a result of reflections/scattering from high altitude noctilucent mesospheric clouds; signals with this mode are usually very weak.

18 May 2011

Old QSL cards

Clearing the loft today I came across several QSL cards from my first year in Cambridge back in 1971 including this one from Bob G3WKW for a QSO across town using my 1 transistor 2m TX on CW and FM. I cannot recall the details or how I obtained the FM. Power was just a few milliwatts into a dipole in the downstairs room in a terraced house. Bob went on to work for Motorola before retiring in Hampshire a few years ago. We still keep in contact.

15 May 2011

137.5kHz WSPR

Several stations on 137.5kHz WSPR tonight. G4WGT is testing a new rig, M0PPP is getting decent reports and me getting reports from just G3XIZ so far. Will leave WSPR running for a few hours and see what happens.

14 May 2011

QRSS30 QRPp beaconing on 137kHz band

PA3FNY's reception of the QRSS30 beacon XBM (me)
My QRPp QRSS30 beacon sending "XBM" is active on 137.7679kHz (approx) from now until around 2300z. As before, any reports and screen shots would be much appreciated. ERP is still around 50uW. The last time it was on it was copied in Holland and again today, this time by Victor PA3FNY (see screen shot above) at a distance of 328km.

G3XIZ TXing on VLF today

G3XIZ is active this morning on 8.9766616kHz and clearly visible on the G3ZJO grabber in Northampton. His signal was a lot weaker than the last few times for some reason. I think the difference is at my end.

12 May 2011

Bloody-nosed beetle larva in IO80ef square

About 1.5cm long, behaved like a woodlouse.
Walking part of the coastal path in Devon at Prawle Point I noticed this very strange creature in the footpath a few metres from the cliffs. It looked a bit like a fat slightly iridescent woodlouse about 1.5cm long with a very wrinkled outer shell. There is a video of the creature moving at http://www.youtube.com/watch?v=rSDiJA1b1zM . It turns out the creature is the larva of the Bloody-Nosed beetle, which is quite common in the southern UK.

8 May 2011

A beautiful QTH locator square

Bolberry Down - Devon UK - IO81CF
Ever wondered what one of the most beautiful QTH locator squares in the UK looks like? Try IO81CF in South Devon. This is a view along the rugged clifftops just below Bolberry Down which was the location of one of the first ever 6m contacts between the UK and the USA by G5BY back in the late 1940s. I was walking here earlier today when this photo was taken.

ZEVS DXing on 82Hz (yes 82Hz!)

Several stations are reporting reception of the Russian ZEVS station that operates daily around 82Hz (ELF) sending coded messages to Russian submerged submarines. G3ZJO has copied it as has Chris G3WCD. When I get back from Devon I must try too. I think I should be able to copy it. The attached image is the signal as seen by G3WCD this evening. The signal is FSK coded. Data rates at these low frequencies are very low.

USA 4m beacon

WE9XUP is a new 4m beacon operational on 70.005MHz from FM07tm square that will be running 24/7 until 1.9.11. 4m is not allocated as an amateur band in the USA, so this is just a special propagation beacon. It could be a very useful indicator of multi-hop Es or other modes that may fleetingly open up the transatlantic path on 70MHz. Transatlantic 4m QSOs have been made cross-band more than once. I am not sure if this beacon supports weak signal modes like JT65 or WSPR, but that would be very useful.

7 May 2011

"Enough" - a book by John Naish

May I recommend this brilliant book reflecting on the sheer stupidity of our endless striving for better and more when we already have more than enough? We have evolved into a race chasing the impossible dream that ends up with us all stressed out, depleting our resources, unhappy and unfulfilled. The author argues we need to develop a cultural sense of "enoughness" and to be happy with what we HAVE rather than always striving for more and better.

I couldn't put this book down and all the way through was saying, "yes, spot on" again and again and again. Having read the book I doubt any of us will instantly change our ways, but just maybe we will reflect on our culture and modus operandi and think a bit more carefully about what is REALLY important in our lives.

The book is not a dull, environmentalist tome. Rather it is full of humour and light-heartedness. A truly excellent read for western man in the 21st century. I suspect this book will be seen in years to come as the book that woke us up and brought us to our senses in much the way that Rachael Carson's "Silent Spring" did back in the 1960s.

Robert Helliwell

The death of Emeritus Professor Robert Helliwell of Stamford University was announced today. Helliwell was the author of the book "Whistlers and Related Ionospheric Phenomena" back in 1965. This is a wonderful book on the subject of VLF atmospheric physics which is still available from Amazon.

My 50uW ERP signal at 45km on 137kHz in QRSS30

Chris G3XIZ has sent me a nice screen shot showing my QRP beacon signal a couple of days ago. The signal is in QRSS30 and as Chris says, certainly good enough for a 2-way QRSS QSO on 137kHz. Chris is 45km from me.

Bluebell woods

Just spent a pleasant afternoon walking through an old wood near where I used to live in Devon. The woodland floor was a carpet of bluebells and garlic flowers. This is the first time I'd been back there in around 40 years and it was as lovely as ever.

5 May 2011

Ultra low voltage oscillators

Thinking a bit more about my crazy idea for a mains hum powered QPRp beacon TX, I chanced upon this page which discusses FETs running from extremely low voltage supplies. See http://www.dicks-website.eu/fetosc/enindex.htm. Some of the zero threshold voltage MOSFETs (ALD110900A) used in sensitive crystal sets may also be useful in this application. The link shows an FET oscillator powered by just a thermocouple producing only 13mV! Incredible. See also http://cap.ee.ic.ac.uk/~pdm97/powermems/2009/pdfs/papers/069_0209.pdf and http://www.aldinc.com/pdf/Ultra%20Low%20Power%20Oscillators.pdf

4 May 2011

UK trains - actually pretty good

For the last couple of days I've been down in Canterbury visiting my son, his wife and our grandson. As my wife was busy I took the opportunity to travel alone by train. There is now a new high speed service from London to Canterbury that has slashed journey times on that part of the trip. All trains were clean, on-time, fast and comfortable. Also, at £25.50 return with my senior railcard, excellent value. We complain too often, but railways in the UK are actually rather fine of you can travel off-peak when the commuters are not crammed in. As an ex-trainspotter back in the late 1950s and early 1960s I still love trains.  Secretly I'd like a Ian Allen locospotter's book (now Platform 5 books) so I could collect numbers still, but would risk being called a sad anorak!

1 May 2011

325km with 50uW ERP on 137kHz

Well, Henny PA3CPM has just sent me a new screen grab showing my signal at 1041z today on 137.676kHz in QRSS30. This time you can make out some of the CW (visible just below the continuous Loran line) and the periodicity between callsign blocks is visible confirming this is indeed my signal.  Distance is 325km (202 miles) to JO22mb square. This is the first time my 137kHz signal has got into mainland Europe. I am amazed that a really simple beacon on a tiny board into a simple wire loop in the garden can span such distances. Even more amazed that Henny could find it!

30 Apr 2011

Over 100km on 137kHz with 50uW ERP

Just got a screen grab from G3WCB 101km away showing my QRSS30 beacon signal being received at his QTH near Windsor. Mine is the lower trace in which you can see "BM" (part of XBM). It is not strong, but there. I will leave the beacon running with around 50uW ERP during today.

A few hours later G3WCB got me stronger with the XBM very clear on the screen.

Henny van Elst in Holland was also seeing traces at the right frequency, but too weak to positively identify.

29 Apr 2011

QRSS3 beaconing on 137.6748kHz

My QRSS30 (slow CW) LF beacon has just been started up. I'm hoping that QRSS30 will get me reports from a bit further afield.  Any reports and screen grabs would be much appreciated. It will be on for much of the weekend unless I need the antenna for some VLF tests. The message cycle takes about 25 minutes and best results will be with Argo, Spectran or Spectrum Lab software on a PC and FFT bandwidths of around 0.1Hz.

Message:    
XBM in QRSS30, pause, then G3XBM in 10wpm
Freq:           137.6748kHz
ERP:           50uW (antenna 80sq m vertical loop)
Location:    JO02dg, Burwell Cambs