MF WSPR activity at an all-time high

MF WSPR activity this evening

This evening the 472 and 500kHz bands are humming with WSPR signals and those monitoring for them. At the last count there were 40 stations either on RX or TX WSPR. No great DX so far this evening here with the best report being from an SWL F59706 who is 560km south of me.

Best DX yet on 8.97kHz earth-mode: 6km QRSS3

Today I went out to my usual test sites to check the performance of my latest VLF earth-mode system. For the first time, my RX loop and preamp could be optimally tuned in the field. At 1.6km the 8.978kHz QRSS3 beacon signal was rock solid (see first image).

5W 8.978kHz QRSS3 earth-mode signal at 1.6km (STRONG)

5W 8.978kHz QRSS3 earth-mode signal at 6.0km (10dB S/N in 0.67Hz BW)

I then moved on to a number of other locations eventually arriving at a spot 6km from the 5W TX where previously I'd only ever managed copy with a constant carrier or QRSS30 (30 second dot CW). This time the signal was about 10dB over noise in 0.67Hz bandwidth on QRSS3, my best ever result at this range (second image).

In the coming week I'll be looking for a new RX test location around 7km or further from the home QTH in the hope of increasing my through-the-ground DX record.

500kHz WSPR Spots

Conditions on HF appear to be very disturbed (according to the propagation forecasts) yet I'm getting plenty of WSPR spots on 500kHz. It will be much better when we all get access to 472-479kHz as, currently, activity on MF is split between this band and 500kHz.

SAQ (17.2kHz) transmission Oct 24th

SAQ, the historic alternator transmitter on 17.2kHz CW VLF will be making a special transmission on United Nations Day next Wednesday Oct 24th 2012 starting at 1010 UTC with the message being sent at 1030 UTC.   Reports from this transmission will not be confirmed by QSL card (some test transmissions are  QSLed).  The transmission is a part of the celebration of the United Nations Day in Grimeton, see http://undayorg.files.wordpress.com/2012/09/unday-english1.pdf.

IC7100 for 1 penny??

Amused to see the Nevada advert for the Icom IC7100 on their website. At this price I would expect this high end mobile/home station multimode to be sold out!

Nice price for the IC7100 !

Earth-mode VLF RX kit updated

Today I've been updating my VLF receiving kit ahead of doing some further field tests, probably on Monday. I've now changed my RX loop so that the resonance can be adjusted in the field using a capacitance switch box to bring it to resonance.  The capacitance to bring it to resonance is around 240nF. The loop was about 1kHz off-tune so that the signal was around 4-6dB weaker than it should have been. Now I can tune the loop for maximum S/N in the field and can adjust the loop to a variety of test frequencies.  I've also peaked the 8.97kHz tuned circuit on my earth-electrode receiver input and fixed a faulty connection cable.

Whether these changes will allow me to get any further through the ground remains to be seen.

What a 500kHz WSPR signal looks like

G6AVK has his temporary grabber running on 500kHz this evening. See http://www.qsl.net/g6avk/ . It was interesting to see what my WSPR signal looks like on a grabber at around 80km away. My report was -24dB S/N but, as you can see, it is clearly visible FSK keying around 6Hz.

G3ZJO builds the G3XBM MF transverter

Over the last few days Eddie G3ZJO has been building a near carbon copy of my 10W transverter for 472/500kHz. I am pleased to hear that the build went well and Eddie is getting well over 10W RF from the unit.

G3ZJO's (very neat) version of my 472/500kHz transverter

Eddie found a couple of errors on my schematic (values shown on my photo are wrong on the circuit) and these I must correct. Once these had been sorted - my fault - the transverter worked fine. I see Eddie is getting some good reports on 500kHz WSPR this evening.

If anyone else builds a copy, please let me know and send me a photo.

Earth-mode 8.97kHz VLF tests

Today I did the first tests using my new 5W 8.97kHz beacon looking for signals at my usual "close" test site 1.6km from the home QTH. Good copy on QRSS3 and even solid copy on 10wpm CW. Copy was using my 30t 80cm loop on RX although results were similar using a 5m spaced earth electrode pair. Tests at greater range over the weekend. This is a recording of the 10wpm 8.97kHz CW signal at 1.6km .

QRSS3 signal at 1.6km using a 30t 80cm loop on RX

10wpm signal at 1.6km using a 30t 80cm loop on RX

As the traces show, there are a lot of strong interfering signals around in this part of the spectrum. With an E-field probe there were lots of telemetry like signals audible which I think are being carried over the national grid overhead cables. These were about 0.5km away from the test site.

Ten-Tec Argonaut VI

Ten-Tec is working on a new QRP radio that is a little larger than the FT817 but with a more conventional styling than the KX3. At the moment I understand price has not been fixed. 25 pre-production units are being field tested.  First shipments are not expected until later this year and there are hints that this may slip.

I am ambivalent about this new design: with limited HF band coverage and no VHF/UHF coverage and a styling that is "plain Jane" how many people will opt for it compared with (a) a new KX3 or even (b) an FT817 despite it being a 10 year old design? It needs to have some pretty strong unique selling features I think.

Interestingly, the Ten-Tec website makes no mention of this radio as far as I can see. Elecraft were forward selling the KX3 nearly a year before it made it out to first customers. Why is Ten-Tec not already seriously warming up the market? Surely if it is to be worth buying they should be encouraging potential customers not to buy a KX3?

The image above is linked from the www.qrper.com website.