Mini-whip shoot-out!

Interest in the remarkable mini-whip antennas - actually e-field probes, rather than antennas in the usual sense - continues here in now rather cold north Wales, where mountain waterfalls are currently frozen solid.

Today saw the arrival of the PA0RDT mini-whip system, which I bought because of its reputation for high-quality build and out of curiosity with how a generic Chinese mini-whip, widely available on e-bay, would compare with it.

Now, the Chinese circuits are perfectly well manufactured to good quality standards and can't fairly be thought of as inferior products. The Chinese unit I bought cost £23 delivered, and it arrived within 6 days from China, even though I ordered it on Xmas Eve. The PA0RDT system, with delivery, costs twice this amount and took 7 days to arrive from the Netherlands.

The two whips, prior to deployment in the night sky. The PA0 probe is less than half the size of the Chinese probe.

 

With the easterly winds lower and the temperatures a bit warmer this evening, I took-off to the lakeside woods, a quiet rural setting free of as much electrical interference as it's possible at low frequencies.

I mounted the probes ('antennas') on separate fibreglass poles. Though there is no interaction as one gets with true antennas, I kept the one not under test at near ground level whilst the one under test was up at 7m and then repeated with the next probe. 

Each system had the sheath of the coax feed connected, via slightly different mechanical means, to an independent ground stake in very moist/wet ground (the PA0 system has a jumper to allow common or independent grounding).

Whilst the Chinese system has a separate grounding connector on the DC supply box, the PA0 system doesn't and you have to, rather less ideally, croc-clip an earth connection to a coax plug. The reception was by the same coax cables and the same RSP1a SDR.

Because my interest is mainly SAQ reception, I listened to low frequency signals for this comparison. They are also much steadier signals than, say, SSB at 80m or something like that.

Let's look at the evidence. First, the PA0RDT system, receiving the UK's Anthorn time signal in Cumbria (and therefore a good ground wave signal at my position, just down the Irish Sea from the transmitter):

And this is how the generic Chinese mini-whip did, a steady 3dB stronger than the PA0RDT system:

Next, let's look at DCF77, the German time signal as received by the PA0RDT system:

And how DCF77 was heard by the Chinese mini-whip, being a full 4dB weaker than the PA0 system:

I'm a bit tired for now to post more videos, but on the local ground wave 198kHz (BBC Radio 4), the PA0 system was 2dB weaker than the Chinese system. But on Algerian radio at 252kHz, the PA0 beat the Chinese system by the same, 2dB.

So it seems on this limited test that the PA0RDT is better by between 2 and 4dB on more distant low frequency signals than the generic Chinese system. I'll do more testing as time allows, hopefully during the early morning, when some South American stations can usually be heard at low frequency.