At 12:52 PM 13/03/2002 -0500, you wrote:
VK6VZ replied:
G'day
My Autek RF-1 suffers in a similar manner from BC-pickup - in this case
from a 100kW BC station some 20km away.
When I put up my Marconi-T with a 66' vertical section, the impedance at
the base measured at the base was waay off from what I expected. I simply
connected my Amidon multi-tap Unun in circuit, using the tap that most
nearly coincided with what the theoretical impedance should be and, hey
presto, everything looked great and just needed to trim a metre or so off
the antenna to put it on 1830 with a 1:1 SWR.
The MFJ and Autek are great instruments, but 160m does cause them a few
problems.
Vy 73,
Steve, VK6VZ
VE3 QAA said:
I think this answer is the only one that makes any sense. I have the same
>problem using an Autek - the reactance can't be reduced to zero with any
>setting of the series capacitor tuning my shunt fed vertical, even though it
>has plenty of range to do so. The reactance comes down to a minimum, then
>rises again as I vary the vacuum variable. The only explanation that makes
any
>sense to me is pick-up of BC station(s). I plan to repeat the measurements
>using a good old fashioned GR bridge, bu haven't go around to it yet. I'm
>betting this will give sensible results.
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