Time to test the Ampro stick-based antenna (price: not the £200 being asked for the commercial version!) at the beach last evening, passing a couple of hours whilst on taxi service for my daughter!
It's simple, and can take good winds. |
Key to the success of this antenna is the requirement for 1/4 wave radials for the band of interest, and the raising of those radials off the ground - even if that is only a few centimetres. With the radials on the ground, the matching is way off. As soon as they leave the ground, matching becomes perfect.
It only takes a small stick to raise the radials enough for a perfect match. |
This outing wasn't long enough to get a good WSPR dataset. All I can say is that, with the tide a long way out, and no seawater-saturated ground beneath the antenna, the stick antenna was nevertheless achieving exactly the same SNR at the DX station, VE6JY, as my full wave delta back home - also a simple but much more complex to deploy antenna (think: elevated feedpoint and ~8m total height) than the Ampro - just ~2.5m tall.
Nice and warm, lying on the coastal grass. |
Overall, though, the stick wasn't anywhere near as good as the delta, as this map shows:
Over on a few bursts of FT4 - at about 3W - the stick is certainly not a dummy load:
And, of course, with any portable antenna, you get the distinct advantage of fresh air and wonderful views. Even a little nibble on the very salty but refreshing sea kale, now in full bloom:
On the horizon is the lighthouse on the remote 'Skerries' - a name revealing of the area's Norse heritage. |
Sea kale. Delicious! |
Below: 6m operation, the following afternoon, cut short due to oncoming heavy rain! Initial assessment is that the Rapsberry Pi causes RFI at 50MHz, so will need some additional ferrites on cables. I was getting to the Azores at -10dB on FT8, whereas my 2-ele quad was only managing -17dB at the time. The radials are significantly less than 1/4 wave, being only about 1m each.
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