Thursday, 21 September 2023

Autumn Equinox Beach WSPR

Yes folks, the equinox that, from this point on, takes us into winter, is upon us again!

I always try to do some WSPR receiving down at the beach, facing the incoming signals along the morning long path, whenever I can at the quinoxes. During the pandemic lockdowns - I shudder to remember them - the ability to get out onto the beach and meet some local people was part of my survival strategy.

Nice, but a bit showery, at the beach this morning.
 

The set-up, for 14MHz, is simple: an elevated 1/4 wave vertical, with two sloping elevated radials, installed on saltwater-saturated sand at the water's edge. On this run, I was using a SDRPlay RSP1a receiver, with a Raspberry Pi 4B doing the business on the WSPR signals.

Whilst it was geomagnetically fairly quiet during the test, it had been slightly rough the previous later evening. This does tend to degrade my performance at 53.2 degrees north (e.g. WSPR signal broadening is common here during rougher conditions, whereas it may not occur at all a bit further south).

A particular station of interest for me is VK3QN, a fixed long-path (to Europe) 14MHz array that is optimised for low-angle radiation. It's owned by Ian, VK3MO and transmits 5W every ten minutes.

I found Ian's signals were not being decoded, once they reached a good signal strength. I had the decode depth on 'normal', whereas 'deep' seems, oddly, to work much better on very strong signals; VK3QN is a solid, saturated line on the waterfall whilst transmitting.

VK3QN fixed long path (Europe) 2 x 6-ele 14MHz array. (C) VK3MO, with permission.
 

In any case, my reception of VK3QN was very good, but the typically-excellent performance of the likes of 2E0PYB, who I think is still using a vertical phased array, not too far from the sea and in a low noise environment, was doing a bit better. That said, the usual disclaimer has to be issued, in that we often don't know (and some won't tell!) what antenna is in use on any given day. We also have to be mindful that, being well east of me, 2E0PYB's long path will peak about 15 minutes earlier than me, so my curve has to be mentally shifted to the left.

VK3QN being heard by various UK stations, 21/09/2023

Feeling a bit deflated that my effort to get up at 5am and brave heavy showers and a cold wind didn't seem to be bringing home the goods, I turned my attention to analysing the signal from VK2DAY. This restored a bit of faith in beach operation, with something around a 9dB typical enhancement over even the excellent stations of 2E0PYB and GB0SNB(/SDR). Nobody else in the UK could hear VK2DAY in this period.

VK2DAY reception, 21/09/2023.

How about VK7JJ, which wasn't being heard very often by anybody in the UK? Turns out I wasn't quite as good as the other two 'big cheeses', but still there with the only three who were hearing him.

VK7JJ reception, all UK stations hearing him, 21/09/2023.

Turning to VK4PK, again only three UK stations hearing him in this period and where I was definitely above 2E0PYB and, overall, about level with G6MC/K.

VK4PK reception by all UK stations hearing in this period.

Where the beach did very well for me was in hearing stations that nobody in the UK - not even 2E0PYB and GB0SNB - could hear during the test period. These included ZL2KR (-21dB/2500Hz, 05:08UT), VK2WQ (-24dB/2500Hz, 06:40UT) and JA5YLT (-23dB/2500Hz, 07:18UT) - though G4HSB, whose data I could not access for some reason, was also reported as hearing that station. With the detection limit for WSPR being about -34dB, this implies at least 13dB enhancement for these stations, relative to the other best stations in the UK - and much more than this, compared to a typical UK receiver.

Zl2KR spots, heard only by me in the test period.