Hello Bernd, group,
I just had a look at the webpage, and as any other EH- (or CFA-) antennas
that is claimed to work well it is at a respectable height above ground
(based on the pictures I guess about 10m). Most likely the EH-antenna just
acts as the funny looking top-hat of a vertical antenna.
Scaling up the 160m version (1.5m long, 35cm diameter at 10m height) to
136kHz would result in a 20m long, almost 5m diameter construction at 130m
above ground. I have no doubt that this would be a great 136kHz antenna ...
assuming you can build such a construction.
For 136kHz a 6m high, 2m diameter construction is proposed, let's say with
the lower end 3m above ground. Downscaling that to the topband results in a
44cm high, 15cm diameter with the lower end at 22cm from the soil. I wonder
if such an antenna would be worth anything (be sure to dig the coax in the
soil to avoid that it radiates more than the antenna).
73, Rik ON7YD
At 14:44 13/02/2003 +0000, you wrote:
Hi all,
for one who is interested in getting more practical information, there is
a URL:
http://www.qsl.net/iz7ath/web/home_eng.htm
where you can find some hints to build this antenna for 160 m. And
furthermore a lot of results in doing qsos with this type of
lowband-antenna. Talino (iz7ath) suggests 6m long cylindres/2m diameter
for 137 kHz. If the loss of efficiency will be abt. 10dB compared to a
fullsize-dipol(measured at 1.8MHz!) then it would be a hope for all
lowfers with large aereas and tolerant neighborhood :-))
73 Bernd, DF8ZR
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