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Old October 14th 07, 11:16 PM posted to rec.radio.amateur.antenna
cliff wright cliff wright is offline
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First recorded activity by RadioBanter: Jan 2007
Posts: 58
Default Imbalance in doublet antennas.

Good Day all!
Now I have my Kenwood ts-820S going on TX again I must turn my attention
to another problem.
This is entirely a result of my house and section layout.
I have a G5RV antenna supported by a 7.5 metre mast in the centre on a
quite steeply sloping section.
The antenna runs East/West. Now thw western (high) end is supported by
my upper fence posts on top of a timber retaining wall totalling about 4
metres AGL. The antenna wire is substantially horizontal at that end.
The eastern end however has the problem of a mast of any greater than
3.5 metres high interfering with our neighbours view and they are very
good neighbours!
As a result the eastern end of the G5RV slopes down at about 20 degrees
and is only 3.5 metres AGL at the end.
Now I have noticed that my "Z" match antenna tuner is much more critical
in adjustment than it used to be with a horizontal G5RV at my previous QTH.
Obviously the capacitance to ground will be very different between the 2
sides of the doublet and I have a fair amount of mains borne QRN
here. Has anyone else sorted this problem, it will not be easy to move
the antenna as my section is only 860 M2.
&3's Cliff Wright ZL1BDA ex G3NIA