Thursday 30 January 2020

(Yet) Another trip to the Beach - and a magazine article!

Yesterday, I noticed a fairly new callsign on 14MHz WSPR - DU6/N7MOT, operated by Lenny, a very friendly chap as it turned out.

Lenny's sending out quite a lot of power for WSPR - 20W - through a hexbeam pointed at the USA.

I was curious to see how Lenny's signal might be enhanced down at the beach with a stick antenna on the car, compared to my slightly-inland, hilltop-based vertical delta loop on superb ground and rural quiet RF conditions.

Geographical reach, TX and RX, MW1CFN/M from IO73vh (beach)

The delta loop received Lenny four times in about 80 minutes, whilst my stick only received him once.  I think that's because the path was changing at the time.  Even so, at 08:46, my stick received Lenny at -9dB, and the delta at -18dB.  Very typical of the enhancements seen in past missions to the beach.

In terms of transmitting from the beach, the results are quite remarkable.  None of the following stations heard the 1W from my delta loop, whereas they all heard the stick at very good signal strengths: ZL3JE, Zl2BCI, JH3APN, BG7IBS, BA7KW.

The plot below shows ZL3JE receiving my stick antenna's 1W, peaking at -17dB SNR.  The limit of detection at the moment with WSPR software of all varieties is -34dB.  Because the delta loop was not heard at all by ZL3JE, this implies an environmental gain provided by the beach of at least 17dB on this specific path at this specific time.  Not all paths and times will realise this spectacular result, of course, but it is certainly available for limited periods.

That's the kind of gain you can only dream about from home.  This work really reinforces the conclusion that operating from a home environment, even if it's RF-quiet and only a km or two inland, is very much a compromise that won't ever realise the potential available from the beach.  That, and the fact that you won't ever suffer from neighbours installing solar PV and destroying your hobby altogether!

MW1CFN/M 14MHz, 1W WSPR received by ZL3JE.
For those interested in testing out beach operating for yourselves, you can do worse than buy a copy of Practical Wireless, where my article about this will appear either in the February or March edition, I understand.

Coming soon!



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