Topband: Detuning a T-vertical

[Raoul Coetzee]

My T-vertical antenna used for TX on 160m is about 15-16m high with a bottom
loading/matching tap, mobile antenna style.
Also in the circuit, across the centre and shield of the co-ax  is a 2000 pf
capaicitor.SWR is good, no heating taking place of any component in the
circuit and I seem to get out well. .Which brings me to my question about
detuning the described vertical during RX. If and when I short the co-ax
from the vertical in the shack, the noise from my rx loop increases.If I
terminate the TX antenna's co-ax in the shack with 50 ohm resistance, the
noise increase on the rx loop.(I thought I would reduce the noise as I hoped
the resistor would absorb the energy from the TX antenna!)
The only cure seems to be (by testing) to disconnect the down drop from the
vertical before it gets to the top end of the matching coil.This would need
what type of relay to achieve this? I know it would be one that would cause
little interaction with the actual TX'ing, high voltage , high current.The
impedance at that point is less than 15 ohms
so maybe high voltage is an over kill?
I hope my explanation makes sense.
B.T.W. Still looking for CA at my SR, about 03:24 UTC
73
Raoul, ZS1REC

Please note my new email :raoulc at smmcape.co.za