Return to the sea!

The weather has turned very autumnal here in North West Wales recently.  High winds more typical of winter, and a very cool airstream have dominated the last week.

My simple /M station, at a different location, working JA, last year.

These are the kinds of conditions that prompt me, like some animal seeking the last fruits of summer, to visit the coast with a HF radio in tow.  Not that I'm far from the coast anyway - just a couple of kilometres, in fact!

So, I decided to see this year if WSPR reception at 14MHz is better down on a small peninsula - Point Lynas - that projects into the Irish Sea from the northeast 'corner' of Anglesey.

/M location: Point Lynas and lighthouse, Anglesey.  Image: J. Rowlands/Pixaerial.com

It's not the widest expanse of sea you've ever seen from the coast, but it does have a nice, clear path to the NW, where signals from the far west of the US come in.

The comparison I was running was hardly fair.  At home - elevated and on a copper mine with a clear view of the sea, I had my vertical delta loop into a FT-450 and a laptop to decode.

At the coast, I had a car with nothing more than a simple, magmounted mobile whip, feeding a Kenwood TS-480SAT and a Raspberry Pi to decode.  The ground here is hard schist rocks of very poor characteristics.

My initial problem was to address RFI from the Raspberry Pi.  After lots of attention to possible ground loops and so on, I found that the easiest solution, and a very effective one, was to power the Pi and its screen from a 22Ah Lithium power pack.  This lasts for several hours.

And the results of about 45 minutes of WSPR data gathering at 14MHz?  Very surprising, given the difference in antennas.  On the longest path, with a direct, clear line across the sea to AA7FV, my mobile whip was hearing that station at -24.5dB, compared with only -27dB for the delta loop.  In other words, nearly twice as strongly into the whip.  K5XL also came in 1.5dB stronger into the whip.

You may want to stop me there and say it was some difference between the hardware.  That's possible, but in practice isn't supported by the other results, which vary in both directions.  Stations for this table were those heard consistently over the operating period (16:58 - 17:44UT, 19/08/19)

 
Overall, the two, very different antennas yield the same, or very nearly the same outcome!  That's quite an amazing result for such a simple antenna, albeit one in a good, yet not perfect seaside location!  The next test will have to be from a location with more sea horizon to the west; it's actually quite difficult to get car access to the coast around here.

This gives a lot of encouragement to the significant fraction of the radio community that only ever operates from mobile or portable situations - a number certainly destined to increase as ever-more electronic RFI blights our home-based radio lives.