Dear Dick, LF Group,
I used three 10m telescopic fibreglass "fishing poles" to set up an inverted
L 136kHz antenna for an expedition to Puckeridge some years ago. The
inverted L had about 40m horizontal section, with a single wire, and with
about 300W I had many CW contacts up to 1000km or so, mostly during daylight
(I didn't have the gear to do portable QRSS at that time). The most
effective ground I tried was 4 x 1m ground rods, driven into the ground near
the antenna downlead. This system achieved an ERP around 0.15W in a good
open field location.
The main difficulty with the fishing poles is that they are very flexible -
I had to use nylon monofilament guys at the ends of the horizontal span, in
order to keep the poles reasonably vertical. I used about 4mH loading coil
inductance, wound on 100mm PVC tubing, in a plastic dustbin to tune the
antenna. I had no problems at 300W, but later experience has shown that
corona will be a problem with this short an antenna wire and 1kW TX power.
The best way to avoid this would be to reduce the voltage by having a longer
antenna, probably 80m or more would be OK, but this would need more poles to
support it.
I missed LX1PD last time around, so would certainly be pleased to work you
in LX!
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: Dick <[email protected]>
To: <[email protected]>
Sent: Wednesday, March 22, 2006 9:20 PM
Subject: LF: portable DX-pedition antenna?
> Any suggestions for a DX-pedition antenna which is easy to built up,
> and as efficient as possible?
> Should be capable of withstanding 1kW.
>
> 73
>
> Dick, PA4VHF (LX/PA6Z..........)
>
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