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

Mark van Wijk, PA5MW pa5mw at
Thu Mar 24 02:38:33 EDT 2016

Hi Bill,

I think this is not what I meant here; I also do use BPF's and the Front End 

The problem is that while listening to your receiving antennas, there is 
also some signal from the transmit antenna getting through thanks to the 
internal cross-talk of your rig's TX/RX relay.

I was wondering what people do besides the obvious 'kill the TX antenna 
input during RX mode' ?

73 Mark, PA5MW

-----Original Message----- 
From: william radice
Sent: Tuesday, March 22, 2016 2:05 PM
To: topband at
Subject: Re: Topband: Post contest season: TX antenna vs RX antenna 
cros-stalk. What do you do?

:::: Serious multi-op contest stations face this issue all the time.
Most use individual band filters and they almost completely eliminate
the issue.
At our station we used the Dunestar filters for operating positions on
different bands. As for 160 I personally use the KD9SV "front end saver"
and it does the job completely.

On 3/22/2016 5:44 AM, Mark van Wijk wrote:
> 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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