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Re: Topband: Single antenna port xcvr but want to employ separatereceive

To: Tom W8JI <w8ji@w8ji.com>, James Rodenkirch <rodenkirch_llc@msn.com>, "Top Band Contesting" <topband@contesting.com>
Subject: Re: Topband: Single antenna port xcvr but want to employ separatereceive antenna
From: "Shoppa, Tim" <tshoppa@wmata.com>
Date: Mon, 13 Jan 2014 16:58:25 +0000
List-post: <topband@contesting.com">mailto:topband@contesting.com>
> If you pull a relay low to go TX and you ever lose power to the relay, lose 
> the relay, or lose the relay path, the system defaults with the transmitter 
> running into the receiver antenna.
> You have to decide if that can damage RX antenna stuff. This requires a fast 
> relay pull in time, and a slow release time..

I've done that several times, usually right after I "clean up the cabling". 
I've had several QSO's with me using the RX antenna for transmit :-).

In fact modeling puts the K9AY loop at 25 or so dB down compared to my transmit 
antenna and this is consistent with observed performance both transmit and 
receive!

I usually run the rig at about 60W out into the amp which puts about 600W out. 
So 60W into the receive antenna, minus 25dB, is around a few hundred milliwatts 
ERP. The better equipped 160M stations within a few hundred miles can still 
hear me but it takes some effort to complete the Q. I know in the yearly NAQCC 
160M QRP sprint, I work easily into the better stations in the upper Midwest 
and NE with 5W.

I think I should sponsor a Stew Perry plaque, "most QSO's made transmitting 
into the receive antenna", but that would be unfair because I would probably 
win it.

Tim N3QE

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