Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do?

Mark van Wijk pa5mw at
Tue Mar 22 05:44:56 EDT 2016

Now that we are  'sort of in post contest season mode' and sharing some good
ideas, there is another question:

During recent Field-day setups I noticed severe cross-talk issues between TX
antennas and the separate RX antenna circuits.
For sure any TX/R relay circuitry offers roughly 50-65 dB dampening. So, during
a contest with >S9+30 signals received on the large TX antennas (Deltaloop for
40m and 80m) these would still show up S1 - S4 on the FD station's K3 RX input. 
At home I normally de-tune my backyard TX antenna(switch to GND during RX) to
avoid noise pickup at the RX antennas, so I never noticed this.

Question 1: how do you manage the TX-RX cross-talk at your setup?

- switch TX antenna to GND during RX
- switch-in en external attenuator, so the cross-talk is below noise level, but
you are still able to use the TX antenna during RX
- any other solution?

Question 2: is there any other basic circuitry or setup in a basic contest
station which offer possible similar negative side effects?

73, Mark PA5MW

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