Latest sunspot predictions (from NOAA)

The very latest table of predicted sunspot numbers for cycle 24 have just been published on the NOAA website. They show a peak of 90 (+/-10) in May 2013. According to the table, the sunspot count will have risen to 45 by this time next year, so we should be assured of some regular USA contacts on 10m next autumn.

500kHz transverter (breadboard) photo

This is a photo of the 5W 500kHz transverter breadboard in its "raw" state. In the next couple of days it will be rebuilt tidily into a small aluminium project box and should look a lot neater. Still, isn't it amazing that something this rough on the bench top can work so well and be heard 951kms away!

Power harvesting IC - runs off 20mV produces 5V

This week's Electronics Weekly has a link to Linear Technologies new power converter IC (LTC3108) that can run from 20mV and deliver 5V. It is designed to be used with Peltier effect devices and similar sources of low voltages, but it could be used with the DC power derived from a crystal set.

Weather and 500kHz antenna matching

It surprises me how much my antenna matching changes depending on weather, temperature etc. I use my simple ferrite rod ATU for the main antenna tuning (tapping down the coil for best antenna and TX connection but I make final adjustments using my little Elecraft auto-ATU at the shack end of the feed coax to the remote ATU in the back bedroom near the antenna. If it rains or the weather is cold, I need to rematch the T1 ATU to get best SWR.  I guess this is all due to the ground losses changing in wet weather as a result of changes in soil conductivity.

A new report from Germany on 500kHz

Last night I was copied, just, at -30dB S/N, by Veit DL7ET in JO31 square at 468kms. This is now my 47th unique station report on the band (well 49 if you include 2 CW contacts). At some point soon the antenna for 500kHz will have to come down so I can re-erect my 28MHz antenna, but maybe not for a couple more weeks.

The next QRP project?

Having finished the 500kHz transverter to my satisfaction I'm mulling over the next project "big idea" to keep me amused on a winter afternoon. I do want to build some homebrew gear for 28MHz as this remains one of my favourite bands: antennas are small and unobtrusive, DX is not hard to work with QRP when the band is in good shape, and the frequency is low enough to be able to make gear, and get it working, with my limited test equipment. Maybe I should do it in stages:

1. A direct conversion mixer and back end with CW/SSB filter bandwidths.
2. A direct-conversion 28MHz front end mixer and RF filter based on an SBL1 or NE612/602.
   
3. A stable mixer-VFO covering the CW and SSB part of the band.
4. A driver and PA for up to 5W.
5. A DSB mixer module to use with the above to use in a simple DSB transceiver.

Scottish DX on 500kHz

After no luck on CW I returned to 500kHz WSPR and was immediately rewarded with 3 spots including one from GM4PMK in the west of Scotland in IO66 square some 615kms to the north west of me. He's spotted me before but this is my first report from him in several weeks. He is reporting Andy G4JNT some 20dB stronger than me, which is consistent with the difference in ERP (Andy is running 200mW ERP and I am running around 1mW ERP).

500kHz CW activity tonight

Several DX stations on tonight on 500kHz CW. OR7T was calling LA3EQ (recently allocated the band in LA) and OZ8NJ was a good signal working G3DXZ. So far tonight, with all this excitment, no-one has heard my 1mW ERP signal on the key! WSPR is much easier!

500kHz full transceive transverter with 5 extra parts only ..and no relays!

I've now modified my WSPR tx up-converter to a full TX/RX tranverter suitable for WSPR, QRSS and CW  in a very simple way, making use of the FT817 split facility which allows you to RX on 500kHz and TX on 28MHz. By adding a series LC between the TX PA and the FT817 input/output RF connection (with back-to-back diodes at the L and C junction, this allows "pass through" from the 500kHz ATU to the FT817 on RX (tuned to 500kHz). On TX, the diodes conduct and the C part is in parallel with the first cap in the TX low pass filter. This scheme is now working really well with good RX sensitivity and no change in TX power out.

500kHz WSPR summary (1-2mW ERP or less)

After about 3 months on 500kHz WSPR, I've now been decoded by 44 different stations in 19 grid squares in 7 countries with best DX still SM6BHZ at 951kms.

Today I got some reports from Sam G4DDK, better known for his RadCom microwaves column - nice to see him listening on 500kHz.

10m/40m WSPR

This afternoon, for a change, I've been putting out a signal on 10m WSPR as my vertical on 500kHz can be resonated on 28MHz using the Elecraft auto-ATU. So far nothing heard here and no reports.

All was quiet so I moved to 40m where instant reports at 5W, then 500mW, from all over Europe. Now testing at 50mW output.

New grid square and station report on 500kHz

Just got my first WSPR report from Brittany, France from F5JNV in IN98 square at 427kms. This is now my 41st report so far on 500kHz. A 42nd report was received from a G SWL a few minutes later.

SAQ (17.2kHz): extra transmission Dec 10th 2009

There will be a CW transmission with the Alexanderson alternator at SAQ on 17.2 kHz on Dec 10th 2009 at 08:00 UTC and again at 16:00 UTC the same day.

The reason for the extra transmission is a centenary commemoration of the Nobel Prize given to Guglielmo Marconi and Karl Ferdinand Brown. SAQ does not want QSL-reports this time and will not verify. They still intend to continue with their annual transmissions on Christmas Eve (morning), Dec 24, at 08:00 UTC with tuning up from 07:30 UTC.

This is always a great opportunity to try your hand at VLF CW reception either with a simple up-converter, direct conversion RX or even a software receiver totally implemented on a PC.

Back on 500kHz WSPR (TX)

Having just got some more IRF510 FETs from the GQRP club I've rebuilt my 500kHz PA and got it working properly towards class E. As long as the antenna is close to 50 ohms the PA hardly gets warm (on a WSPR TX cycle at 5W RF from the PA) as the efficiency is now so good.

Will run the 500kHz WSPR beacon overnight tonight then plan to modify the PA and ATU to 136kHz for a few days. 136kHz WSPR tests will run over the weekend if things go to plan. ERP will be even lower than on 500kHz, but I'm hopeful of some reports. If you get a chance to listen and report (via the WSPR database) I'd be most grateful.

The new TX PA is working well: I've had a 0dB S/N WSPR report from F6CNI near Paris!

RXing on 500kHz this evening

Although I cannot TX on 500kHz at the moment (should be back on next week), I am listening again this evening and hoping to copy G3ZJO who is testing his station on WSPR. Not heard him yet but will keep listening.

Off 500kHz TX for a few days

Our little 2 year old grandson has come to stay for a few days, so I'm unlikely to get much operating time until Sunday evening. I have to rebuild my PA before I can get back onto 500kHz TX, so it may well be next week before I'm on the band again. I shall try to listen as and when I am able. The main information I've gathered on FET PAs (especially in class D/E) for 500kHz is to make sure the antenna is well matched (i.e. don't adjust the ATU/matching when the PA is on), don't exceed the peak voltage rating on spikes, ensure that parasitic oscillations are well suppressed and be generous with the heatsinking.

Another oscillator calculator

Harry Lythall SM0VPO has a most interesting site full of ideas. Among the useful stuff is an oscillator calculator which allows you to work out values of L and C to make an oscillator that Harry claims always works. The circuit produces about 20mW.

This is the link http://web.telia.com/~u85920178/blocks/osc7m00.htm

500kHz WSPR - back to 100uW ERP

Having blown my 3rd IRF510 PA because of overheating, I decided to go back to my 700mW PA based on a 2N3906/2N3904 pair until I rebuild the transverter with a decent heatsink. This PA is bullet proof!  Having made antenna improvements since I last ran this ERP, it will be interesting to see what reports I now get. So far, just M0BMU and G7NKS at -10dB on the reports when running 1-2mW, so all is as expected.

WSPR and DXCC

The following is an extract from a posting on the LF reflector and may suggest getting QRPp DXCC may have become a whole lot easier:

"The discussion at the RSGB meeting noted the ARRL’s position that essentially if two stations make WSPR reports with each other and this is confirmed by QSL or some other approved method then there has been a two way exchange of call sign, report and other info e.g. locator and that qualifies as a QSO for DXCC purposes."

This may surprise some, and did me.

Does anyone know precisely what the ARRL has said regarding DXCC qualification and WSPR? By the definition above I "worked" VK6POP with a few watts of WSPR on 40m earlier this week.

As someone pointed out, a lot LESS data is exchanged in an HF contest, when often the callsigns are not sent (very often) and reports are meaningless. At least with WSPR you get the full calls, location and QTH locators exchanged.

Blown my 500kHz PA ......again

My IRF510 500kHz PA has a tiny heatsink (soon to be addressed when a new heatsink arrives) and it is not very tolerant of poor antenna match. As a result it died again this evening in mid WSPR! This afternoon I managed to raise to PA output to 8W by changing values and this must have made the tiny heatsink just too small to be useable. I also need to find a better way of getting my antenna tuned to 50 ohms.  This is all a good excuse to do a proper rebuild next week.

Belgium gets 4m allocation

With immediate start all radio amateurs in Belgium holding a full licence have access to 69.950MHz (+/- 5kHz) with 10W EIRP on a non-interference basis.  If you can read French or Dutch there is more information here.

New WSPR DX record tonight (40m)

Trying out WSPR2 on 40m this evening and just got a report from VK6POP at 14465kms, which is a new DX record for me. I was running 5W to my 500kHz antenna tuned via the Elecraft T1 ATU. It must work pretty well on 40m!

First experience with WSPR 2 (new version)

Well, it works. I deleted the old version from my PC and installed V2 tonight. Set-up was straightforward and I like the slider to set the TX percentage. Also 500kHz is now one of the default listed bands (600m). My first TX was spotted (with the new version) by I2IAL on 40m.

WSPR 2.0 now available

WSPR 2.0 introduces a number of new features including a  user-friendly setup screen with drop-down selection of audio devices and rig-control parameters, support for compound callsigns, fine selection of the fractional time for transmitting, and a Tune button.  A new Advanced setup screen offers optional CW identification and tools for frequency calibration and automated frequency corrections for your radio.  Full details are presented in the WSPR 2.0 User's Guide, which you will need to read in order to use the new features.  For the first time, a binary installation package is made available for Ubuntu Linux (versions 8.10 and later), Debian 5.03, and other Debian-based 32-bit Linux distributions.

WSPR available at http://physics.princeton.edu/pulsar/K1JT/wspr.html 

Sunspots - blimey!

Just seen the sunspot count for today - 29 - which is pretty good for where we are in the new cycle. It is very clear that sunspot cycle 24 has got into gear and next year should show considerable improvement on bands like 10m.

Birthdays

It was my elder grandson's 2nd birthday last week. We went to Paris to enjoy it with his French grandparents and had a good time. This is a picture of both grandchildren when they came to stay a few weeks ago. It is my wife's birthday next week, so I'd better get thinking. Mine, just before Christmas, is easy as I tell my XYL what I want - usually some radio books.

500kHz PA blown - my fault

My IRF510 500kHz PA just died on me as I TXed for a full WSPR slot into an open circuit (the wrong coax connected!). It won't take 5 minutes to fix tomorrow, but this evening I'll WSPR on some HF frequencies for a change.

500kHz - USA reception this evening

The 5W ERP beacon of W17XSH (the "WSPR shortened" call of WD2XSH/17) was copied here very well just after midnight. This is my first transatlantic WSPR reception and only my second 500kHz station heard from N.America.

Overnight my 500kHz WSPR beacon was running but no new stations reporting me when I checked at 0700z.

8th country on 500kHz WSPR

Just got my first report from Wales tonight with a huge (for me) -6dB S/N report from GW3UCJ in IO81 at 286kms away.  Also a new reporter from Belgium ON6EO. Reports are very good tonight so the WSPR beacon will run overnight.

136kHz WSPR tests (soon)

Very encouraged by my results at 500kHz, I'd like to try some "low ERP" WSPR tests on 136kHz using the same small antenna and transverter (slightly modified).  Ideally I'd need stations like M0BMU, M0FMT, G7NKS and others not too far away from JO02dg to TX and to listen out for me, as these stations get a good signal from me on 500kHz.

Please would you let me know if you'd be able to listen and upload 136kHz WSPR spots sometime in the next week or so? As yet I am not quite ready to start, but I'll let you know when I am.

Presentation on CW and other weak signal modes

Andy Talbot G4JNT has put an interesting presentation about weak signal modes onto his website. He gave this talk at a recent Microwave Round Table. See http://g4jnt.com/MartleSham.htm. It is exploring how we can push the boundaries further when working with very weak signals.

My first 2-way CW QSOs on 500kHz

This afternoon, just after midday, I worked Mal, G3KEV, in Scarborough for my first 2-way CW QSO on 500kHz. I gave him 569 and he gave me 529. Then at 4pm I was called by Chris G3XIZ who gave me 579. ERP at my end around 2mW.

Report from 7th country on 500kHz

This evening I got my first report from Germany on 500kHz WSPR - DK6NI in JN59ln at 805kms. This brings my countries total to 7 now.

FT817 successor coming?

Has anyone heard any intelligence/news on what is happening at Yaesu regarding new hand-held all-band, all-mode, successor to the FT817 with new features such as internal auto-ATU, speech processor, maybe 70MHz included on EU version, LiIon battery pack, etc...

Transatlantic 500kHz reception - VX9MRC

This evening at around 2200z I heard my first ever North American ham station on 500kHz. VX9MRC, the beacon operated by VO1NA was coming through on CW (about 10wpm) on 507.77kHz in and out of the noise at about RST339 at best. On WSPR he would have been solid copy.

A 30th reporter on 500kHz

Lots of trouble getting my 500kHz antenna to match tonight, so late getting on to WSPR tonight. To my surprise (as the antenna current was lower as a result of the rain I think) I got a new report from France - F6CNI in JN19qb which is 418kms away.

Back home - on 500kHz tonight

Just been to Paris, by Eurostar, for our elder grandson's 2nd birthday. At home, the 500kHz antenna is being battered by the very stormy weather at the moment, but I hope to be on the band again tonight ..... if the antenna and roof are still there at teatime.

Voice powered transatlantic 20m test

AA1TJ's historic attempt to span the Atlantic with just a "voice powered" TX (powered only with DC generated by rectifying audio from a LS into which he was shouting) started at 1500 UTC on Tuesday Nov 10th. Power out was about 15mW QRP from the coast of Maine, USA. They had a 2el vertical antenna aimed at Europe and a good clear sea path, but unfortunately the test was unsuccessful, although they did make contact (not voice powered though) with Europe on 160m QRP. For a report see http://www.QRPme.com .

Norway gets some new bands

Stations in Norway now have new, quite large, allocations at 500kHz, 5MHz and 70MHz as well as certain other changes. If you can read Norwegian, see http://www.lovdata.no/ltavd1/filer/sf-20091105-1340.html ).

SM6BHZ hears me on 500kHz WSPR

SM6BHZ heard me at last on 500kHz WSPR at 0556z this morning, so my best DX has now gone up to 951kms with the tiny station. He reported my WSPR signal at -26dB S/N. The distance beats my previous record on the band by almost 100kms. Gus, thank you so much for country number 6 on the band and Joe K1JT for designing the software to make this possible.