[Fwd: LF: Canary Islands LF tests (ON7YD)]
Mon, 11 Jan 1999 07:52:01 -0500
Rik Strobbe wrote:
> During my 1 week holiday on Gran Canaria (30 december - 6 january) I took
> some time to do a few tests on LF.
> Here comes an overview :
> The QTH was Arguineguin in the most southern tip of Gran Canaria. The
> location was about 1km from the Atlantic Ocean, but unfortunately in the
> wrong direction for good takeoff toward Europe. The antenna was a kind of
> T-antenna with a 16 meter top section but only 3 meter vertical part. The
> antenna was on top of a 10 meter high building at 13 meter above ground,
> but only 3 meter above the building. It was matched for 136kHz and via a 12
> meter coaxcable inside the building connected to a Kenwood TS440 (with
> 500Hz CW filter). The building was partly surrounded by higher buidings and
> at only 100 meter distance there were 2 overland HV powerlines,
> streetlights came as close as 20 meter from the antenna. Combined with all
> the 'consumer electronics' in the nearby appartements the result was a
> QRM/QRN level at 10 to 20dB above what I got at home.
> Takeoff toward the UK was far from perfect, about 80km over a mountain area
> with peaks up to 2000 meter before reaching the Atlantic Ocean. Takeoff to
> Italy was slightly better, still about 50km of land going up to 600 meter
> before reaching the Atlantic.
> As soon as I the antenna was ready I checked DCF39, it was only at 5dB S/N
> at daytime, increasing to 15dB S/N after dark. For obvious reasons I was
> not QRV the next night (december 31st), so the first real tests were on
> january 1st. It started good with DCF39 coming up to 25dB S/N soon after
> sunset, but no audibe ham signals. So at 20.00UT I switched to 137770 using
> Spectrogram. Arround 20.15UT a faint trace appeared very close to 137770,
> the trace got stronger for some minutes but then weaker again and
> dissapeared arround 20.55UT. When I checked DCF39 again at 21.10UT it was
> back to 15dB S/N as it was the first night. The signal I saw on 137770 was
> very stable in frequency and it was 'keyed' (stopped and restarted abrupt),
> but too weak to make up real CW code. But both my father (ON8RI) and I had
> the strong impression that there were far more 'dashes' than 'dots'.
> The next evenings I checked the band regulary but DCF39 got no better than
> 15dB S/N. Unfortunatly I received an e-mail from G3LDO too late, so while
> he was transmitting QRS on the evening of january 3rd I was having dinner
> celebrating my birthday.
> There were a lot of indications that the trace I saw on january 1st was the
> signal of Marco, IK1ODO :
> the trace appeared at the right frequency, at a time that Marco was
> transmitting and at the same time DCF39 was also very strong (compared to
> the other days). And although it was not possible to make up CW code it was
> clearly a 'keyed' signal.
> Initialy I only determined the frequency of that signal with the 10Hz
> resolution of the TS440 and thought of methods to get a better accuracy
> (with only the TS440 receiver at hand). So I came to the idea that, instead
> of trying to determine the exact frequency of that signal, I could just
> measure the frequency difference between the signal and DCF39 :
> With the TS440 set to 138.17kHz I got the signal at an audio tone of 401Hz,
> when I tuned the TS440 1kHz higher (139.17kHz) I got DCF39 at an audio tone
> of 462Hz, so DCF39 is 1061Hz higher in frequency than the signal. Back home
> I used a WAV file I recorded from one of Marco's transmissions to compare
> it with DCF39 and the result was a frequency difference of 1060Hz. The
> audiofrequencies were measured using the Spectogram and putting the cursor
> on the trace, giving a resolution of +/- 1Hz. So the 1Hz difference
> (between 1061 and 1060Hz) can be explained by this.
> As a result of the above I came to the conclusion that the faint trace I
> recorded was most likely the signal of IK1ODO,but it was not possible be
> identify it 100%. Distance between IK1ODO and EA8/ON7YD was 2806km.
> Taking into account the rather primitive antenna, the high QRM/QRN level
> and the far from perfect takeoff toward Italy I thing that a better
> equipped station in a more rural area at the norther part of the island
> should be able to copy signals from Europe, for sure using QRS and under
> good conditions maybe even audible CW.
> A final remark : From EA8 to the UK and Italy is about 2800 to 3200km in
> almost north-south direction (10 to 20 degress beam angle to UK, 40 degrees
> to Italy). Recent experiences with OH1TN have shown that 136kHz ionospheric
> propagation is often much better in more northern regions. So I think that
> there is a very good chance to be able to cross the Atlantic Ocean between
> Ireland / west UK and the eastern part of Canada (Newfoundland). The
> distance is a few 100km more, but the path is very northern. So maybe we
> should look for some hams (or LF listerens) in VO or VE1 who are interested
> in some tests or even a crossband QSO on 80 or 160 meter.
> 73, Rik ON7YD
> Rik Strobbe ON7YD
> Villadreef 14 B-3128 Baal BELGIUM (JO20IX)