Rik Strobbe wrote:
At 09:21 17/07/99 +1200, ZL2CA wrote:
>Hi all,
>One New Zealand amateur, Bruce ZL1WB, uses a very long wire strung out
>over a gully, and with only 30 watts of RF power applied, is the most
>often copied ZL LF amateur station in Australia (spanning the Tasman
>Sea, a definite sky wave path, signals are zero much of the time during
>daylight hours). So there is a suggestion that the very long wire that
>is mostly horizontal in nature does provide good LF DX.
Any idea how high (above ground) the antenna of ZL1WB is ?
I might have acces to a 800m (0.36 lambda) abandoned telephone line, but
the wire will be only about 6 meter above ground. Will this work or will I
only get in the Guinnessbook of records for the largest dummyload ever ?
The long wire straddles a deep gully, but the wire has considerable
sag. The wire is a thinner type of power line wire, as it needs to
survive strong wind conditions. Conventional wooden pole supports are
used, and height above ground is only 4 or 5 metres in places, but
obviously the route is strategically placed to get a good span of the
main gully. I have visited the farm site, but it is difficult to
describe the situation in a brief message. Thus the sagging wire, over
an irregular terrain gully, is fairly difficult to model with software.
But whether or not it is adequately modelled, ZL1WB has done very well
with log book entries and QSL cards.
I think it is worth trying long wires in practice for LF transmitting,
and whether it breaks records for dummy loads or DX will soon be
apparent. Not many amateur sites have room for a very long wire. In
this respect, the ZL1WB long wire has a remote controlled transmitter,
as the "selected site" is a few kilometres from his QTH, at a farm
building with mains power.
Regards,
Bob ZL2CA
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