Tuesday 31 March 2020

Amateur Radio - the Covid-19 Files.

How is your Covid-19 crisis going?  Here in the UK, as many countries, there are fairly severe restrictions on travel and general movement.  In essence, we can only leave the house for shopping, work that cannot be done at home, and other such essentials.

Courtesy Mark For Europe, FB.

As it happens, all this difficult situation has come just when I have been examining two different WSPR sets ups operated by Ian, VK3MO.  He has a multi-Yagi array on one tower, which is a general installation.

Ian's second tower is also a multi-Yagi array, but optimised for low angle radiation.

Luckily, I'm being paid for an article about WSPR, and some of the work for it can only be done from the coast.  So that permits me to legitimately leave home, as does the need to exercise (contrary to what the Police started saying and doing last week, driving to exercise locations is not prohibited in law - so far).

Early morning long path listening.

In any case, the place I go is so remote that I would never seen anyone on a normal day, let alone a restrictions day.

Interestingly, listening to Ian's long path signal in the early morning has shown important differences between listening sites.

For the morning long path period, as heard at the coast, VK3QN (low angle optimised) was a median 10.5dB stronger than VK3MO.

But with the delta loop back home, the difference in favour of VK3QN was only 5dB - with far fewer reported spots.

This result would appear to suggest that it is very low angle signals at this critical time that yields the excellent difference between the two stations received at the coast.  The delta seems to be picking up radiation arriving from somewhat higher angles, where there is less difference between QN and MO, masking the degree to which the low-angle array is better than the non-optimised array.

So, this all kicks-off another round of work, and one which needs a highly-portable WSPR receiver not reliant upon a heavy and power-hungry, conventional transceiver.

What I need is a new Raspberry Pi 4 model, connected to a SDRPlay RSP1a receiver.  Luckily, I won an SDRPlay competition last year, so I already have a spare RSP unit!

I suppose, though, that it will be necessary to wait until the virus restrictions are lifted - which could take some months - before it is sensible to openly go out onto beaches and play around at the coast.  We don't want to give radio a bad name, after all.

New linear PSU.  A small mass on the top stops an annoying casing hum!

Meanwhile, I treated myself to a new linear PSU yesterday, which arrived overnight, despite the restrictions.  It's already in use on WSPR listening duties, though there is no detectable difference in RF noise, relative to my SMPSUs.

UPDATE: The PSU wasted no time in dying, apparently due to a failure in the large transformer windings.  A hum, smoke and that was it - dead - after just three months!  It's on its way back to Radioworld, but I doubt it's easily repairable.  One to avoid, it seems.