I have an 85 foot shunt fed tower that I use on TB. I have a HI-Z 4
Square
and some short beverages. The performance of the RX antennas definitely
improves (less noise and better directivity) when the TB vertical is
shorted
to ground. What is the easiest mothod to short the vertical to ground?
Do
I need to put a relay at the base of the verticaland activate a relay?
I'm
using a Microham Digikeyer for myinterface and the rig is the FTDX-5000.
Perhaps a set of contacts on one of those units could do the trick. Any
assistance appreciated.
It is not the short that does it, but the impedance reflected to the feed
system at the tower feedpoint.
If a short is helping it some distance from the tower, an open would help it
1/4 wave away.
So, depending on what your radio main antenna port looks like when switched
to receive antennas, you might be able to add 1/4 wave of coax and have
exactly the same effect with no additional switching at all.
Otherwise, you run a risk of creating relay sequencing issues. You have to
be careful, and you must use a relay system and a control system that does
not hot switch a relay.
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Topband Reflector
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