Tiny Watts

Rain was clearing from the west last evening, so I decided to try some WSPRlite transmissions from IO73RF, a local beach with an open aspect from south to NW.

Portable operating is as much about the scenery as it is about the radio.

Unfortunately, I had failed to realise two important things as I rushed to get out: I left my beach transmitter at its previous setting of 5mW, and was using the same callsign for it as I was with the WSPRlite operating back home (at 200mW).  So discerning which station was which was tricky, but not impossible, thanks to the reported power output differences.

Never mind.  It's really just an excuse to look at the sea and get some fresh air (well, lots of fresh air, given the wind!)

I did manage to extract some useful information from WA2TP's reception, where I have taken all other UK stations being heard by him at the time and converted them all into 5mW equivalent signals.  This sounds simplistic, but it is usually very reliable (last year, I could see that G0CCL's 5W and 1W signals were out of calibration by monitoring his reception at a station in the US - to an accuracy of 0.3dB!)

So, on the extreme left (MW6PYS) is my actual 5mW signal as received by WA2TP, and everyone else's 5mW equivalent signal.  The blue horizontal line is the -34dB SNR limit that can be decoded by current WSPR software (WSJT-X in this case):

It's yet another powerful piece of evidence that shows the enormous benefits of coastal operating.  Whilst my received signal was 14dB above the detection limit, all other signals are below it, with 7 of the signals significantly below that limit.  

Put another way, taking 14dB off my 5mW to still be detectable at the lowest decoding limit gives 200microwatts.  Think about that.  It's 0.0002W!

Powers used by others stations ranged from 0.2W to a staggering 10W (sadly, the latter station is MW0NAB, who is blasting everyone in the local area with his signal, yet serving only to demonstrate the uselessness of his antenna system).