VK3MO vs VK3QN (Round 2)

A new test very early this morning, long path, of how VK3QN measures up against VK3MO (details of TX antennas in use given here), using WSPR at 14MHz.

With an incoming tide, and good surf on a steep beach, it's always a little difficult to pitch the receive (1/4 wave vertical) antenna at the correct position.  This was especially so for this run, because I changed from using an SDR receiver to a TS-480 rig and Raspberry Pi 3B+combination.   Moving all this equipment and the antenna in a hurry, if the water rushes in unexpectedly, is not easy!

Listening for VK on early morning long path.  Rig in the box, Raspberry Pi in the bag.

The advantage of using a rig is that all the 'signal processing' is already done by the analogue circuitry of the rig, before being fed to the Pi as simple audio.  This relieves the Pi's processor of the hard work needed with SDR software.

The Pi also never misses a WSPR decode cycle, which can often be a big headache with Windows latptops.  With so much effort involved to deploy in the field, missing cycles is definitely unacceptable!

I'm glad to say that everything went as it always does with the Pi - beautifully!

There was a 2dB median difference favouring QN over MO.  MO peak signal was +21dB (compared to 'just' +9dB to the vertical delta back home), whilst QN, optimised for low angle, reached an essentially identical +20dB (+7dB to the delta).


So, on this occasion, no significant difference in peak signal, but a modest difference in the median of reports.

Obviously, much more work is needed to reach a firm conclusion.

Turning to other VK signals, I was delighted to see I was the only person receiving VK3YE (200mW) anywhere outside of the Antipodes for several hours prior to and during my run.  VK6AS (1W) was also heard, with only VK/ZL and JA hearing him otherwise.  From Africa, only I and the outstanding EA8BFK heard ZS1SCI (200mW) and ZS6JPS (5W).

Example of the benefits of coastal operating.

This was also the case (except for OZ7IT on his peak long path period) for VK3GMZ (10mW).

VK2RH, putting out 5W, was heard outside the Antipodes only by myself, OE9GHV and EA8BFK (no surprises for those two stations!)

In the UK, only GM4SFW and myself heard the 10mW during the run period from balloon VE3KCL, out over the Central Siberian Plateau.

Also nice to see how my peak LP signals were delayed, as would be expected, due to the longitude difference between myself and  excellent WSPR station, 2E0PYB:

VK3QN to me (blue) and 2E0PYB (orange), showing longitude effect.

Covid-19 legal notice: this study, now concluded, was conducted in an unpopulated, remote area, combining my paid work as an author with daily exercise (you try carrying a 12V battery, full rig, antenna and computer on your own through sand dunes!)