Thu, 13 Apr 2000 14:37:44 -0400
Peter Dodd wrote:
> > From Dave G3YMC
> > I wish Larry and the VE team all the best for their forthcoming
> > transatlantic tests - the choice of a period in November is excellent, and
> > if there is a chance then (and December) is the optimum time.
> > I think it would have given Peter Bobek a very special thrill if his aims
> > were met by a normal amateur using normal CW and an average station.
> I don't recall that DJ8WL had any hang-ups about using QRSS - in fact
> all my QSOs with him used this mode
> Of the modes proposed for these Transatlantic tests the extremes are
> 30 or 40WPM CW and slow CW that would take several hours. From
> experiance gained in the last couple of weeks in crossband tests on
> 72kHz/137kHz, mainly with I5TGC, I feel that the following notes may
> be of some interest.
> Even in good conditions a signal radiated from 1W erp is going to be
> very weak by the time it has travelled 3000km, even on a sea path. In
> periods of exceptional conditions such a signal may be audible but a
> much greater chance of success can be had by using QRSS. This can
> illustrated by a 72/137kHz cross-band I had with OH9UFO. Reino was
> using nomal CW on 137kHz. I was a comfortable 'O' on QRSS. I was
> asked to try fast CW and Reino copied his report and gave me 329 -
> then lost it. This QSO was very marginal and if it wasn't for the
> inital QRSS contact it would not have happened.
> We have very little knowledge of the long distance propagation
> mechanism of weak signals at LF. All we can say is (from observing
> commercial stations) that they seem better in Winter at around
> 0400UTC for this path. The greater the distance the shorter the
> openings so digging the signal out of the noise using very long
> integration times is impractical.
> The openings for the I5TGC experiments lasted half an hour, which
> gave plenty of time for QRSS with a dot length of 3 or 4 seconds.
> Exceptional conditions can occur any time so we should not confine
> the tests to special expeditions. We should have a plan.
> Regards, Peter, G3LDO