8.97kHz DX tests Oct 2nd 2010 (DK7FC)

Stefan's latest tests are going well with copy at 902km (Poland) and in Holland and the UK. His signal is stronger than ever before. Well done Stefan. Some stations right across Europe and even in North America are watching.

10m WSPR DX

For a change I went onto 10m WSPR today and was rewarded with a -26dB S/N report from FR1GZ on Reunion Island (9724km away) when I was running 5W to the halo.  Interesting to note the Doppler shift on the signal (and also on the signals from FR1GZ) which suggest movement of the equatorial F layer.

Earlier in the afternoon ZD7FT was a reasonable signal on 10m SSB from St Helena and there were several VE and W's on 15m SSB.

More German VLF radiated DX tests Sat October 2nd

From Stefan DK7FC:

Dear LF/VLF,

My next VLF kite experiment will be tomorrow, saturday, 2nd october :-) After my request to the german air traffic control i got a very kind telephone call at 01:30 AM and later i got the permission to go up to 200 m above ground. See attached mail if of interest for you.

So, if there will be enough wind and no rain, i will try to become QRV at arround  8 UTC.

Tomorrows program:

- (after some resonating tests): Transmitting a short message on 8970 Hz, mode: DFCW-600, hoping to be visible on several receivers in the EU region and maybe Canada and USA (!?)
- Transmitting a CW message (in 12 wpm and in 25 wpm), hoping to be audible at Bernd/DF8ZR (16 km range) and my grabber (40 km)
- Maybe trying a xband QSO 9kHz/144 MHz to DF8ZR
- Transmitting a message on 6470 Hz, mode: DFCW-600, hoping to be visible at many RX, especially Renato Romero who has set up a grabber page at http://www.vlf.it/cumiana/livedata.html
- Transmitting a 30 minute carrier on 8970 Hz which allows long time integration. Paul Nicholson wants to try to record the VLF audio stream from Florida and maybe extract my signal.

- Being visible at PA3FWM at the university of Twente who set up a grabber page at http://websdr.ewi.utwente.nl:8901/grabber.html
- Being visible at SQ5BPF and maybe a russian station?
- Being visible at Paul Nicholson and Markus/DF6NM, of course ;-)
- Finally reaching the 1 A antenna current limit
- and all i have forgotten

I will record my signal of my grabber and will extract an audible signal, if possible. This will be filtered, frequency shifted to 800 Hz and published here as a mp3 file.

My grabber will show the 8970 Hz signal at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html
The 6470 Hz will be visible at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

It is now on the Canadian and US RX stations to make possible what still seems to be inpossible: A transatlantic transmission/reception. The first time my signal can reach a 50 mW ERP limit (wind forecast announces strong wind, so a high kite angle, so a good efficiency!) on 8970 Hz. It is still not sure how the propagation behaves on this frequency at this time and locations so we may see a surprise. Of course any report is very much appreciated, no matter of what distance or country. Every clear reception above 859 km is a new world record by amateurs on VLF!

So, hope the sun will shine at good wind conds and low QRN and high interest :-)

Best 73, CU, Stefan/DK7FC

PS: Markus/DF6NM, will you be on the phone again to make QSP? :-)

More reports wanted on 137kHz WSPR

Continuing to beacon close to 137.467kHz WSPR with about 20uW ERP and getting regular reports from M0BMU (69km) and occasionally others when active. I'd appreciate more reports. It would be interesting to know if others further away can see the occasional 2 minute WSPR burst, but possibly not decode it. 

137kHz receive challenges

Several people have emailed me about receiving signals on 136/137kHz. Now I'm certainly not greatly experienced in this, but a few things I've picked up from others are worth passing on:

• Many HF rigs are deaf on 136kHz, for example the FT817, although this is less deaf if you switch IPO to "on" on 136kHz. A small preamp may help as long as this is selective and doesn't increase overload and intermod from strong out-of-band stations. 
• The receiving antenna may have to be directional e.g. a small loop/preamp to allow local noise sources to be nulled. 
• DCF39 on 138.830kHz sending FSK data with a burst every 10 seconds is a good indicator of receiver performance: it should be a good strong signal in the UK. 
• Ultimately it is S/N rather than noise figure that matters on this band.
• Be prepared to use PC software such as Spectran or Argo to look for weak QRSS mode signals.

Here, I'm using the deaf FT817 (no preamp) with my 80sq m transmitting loop facing W-E at the moment and this is able to receive G8IMR's 20mW ERP WSPR beacon most of the time (188km) despite not being in the main direction of the loop. I've also copied G3XIZ, G3XDV, G3YXM and G3KEV on the band, the last being on CW. So, even a poor receiver can produce results, but it is really worth optimising the set-up (including here at G3XBM) to get more decent results. This is on the agenda.

VE7-JA QSO on 136kHz

JA7NI and Scot VE7TIL completed a trans-pacific QSO on 136kHz this morning, a first between Canada and Japan.  DX is 7162km. This was the result of many months of hard work and planning and followed several previously unsuccessful attempts.

7th new reporter on 137.5kHz WSPR

M0BMU copied my 137.5kHz QRP WSPR signal today giving me -19/-20dB S/N, which is quite a good report. Distance is 69kms. This is now the 7th unique station reporting my WSPR beacon. I'm still hoping for a report from outside of the UK soon, but suspect I'll have to increase the ERP beyond the current 20uW level to achieve this. The consistent signal report from Jim should allow me to calculate ERP based on field strength at a good distance. This will allow me to check the accuracy of my ERP measurements much nearer to home.

Sub-9kHz Amateur Radio group: 100+ members already

Since creating this new group on Saturday it already has over 100 members. Now we need to see some postings from people actually doing activity down there in the "Dreamer's Band".

See http://tech.groups.yahoo.com/group/sub9khz/

A good evening on 500kHz

This evening I was well pleased with my simple 500kHz transverter and the vertical wire loop antenna in the garden producing around 2mW ERP. The map shows stations that reported me on WSPR including LA3EQ at 769km, which is the best DX so far on the loop. The loop doesn't seem to be that directional surprisingly.

137kHz QRP transverter (provisional schematic)

Attached is a first draft of the 137kHz QRP transverter schematic. The values are not all correct or optimised on the circuit. Also the RX preamp has still to be added, but this is what I'm proposing to do. The TX is working pretty well (best DX 148km) and produces around 5W from the PA which runs cool and 20uW ERP. An updated version will appear on my website later. It may even get put in a box soon!