Topband: KD9SV-OK1RR relays ???

[Charles Cu nningham]

I have also used bi-directional 1N4148 diodes across the antenna path, but
I'm re-thinking that approach - If the diodes are not preceded by a good
bandpass - or at least,  a hipass filter in the antenna lead, I'd be
concerned in some instances about the possibility of intermod from nearby,
or strong BC stations.

73,
Charlie, K4OTV


-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Mike
Waters
Sent: Sunday, August 30, 2015 3:52 PM
To: Charles Cunningham
Cc: topband; Tom W8JI
Subject: Re: Topband: KD9SV-OK1RR relays ???

How about back-to-back 1N4148 diodes (2 in series) across the RX path, and a
#47 incandescent lamp between those and the Beverage? That's what I do here,
among other things.

Those are in series with my preamp, which is almost always on. There's also
some variable resistance in series with the lamp and the Beverage switching
relays. I do that so that the signal from the Beverage is equal with the RX
signal from the inverted-L.

73, Mike
www.w0btu.com

On Sat, Aug 29, 2015 at 8:06 PM, Charles Cu nningham <
charlie-cunningham at nc.rr.com> wrote:

>
> It seems to me that a very fast operating preamp protection circuit 
> could be constructed employing a good fast saturating NPN switching 
> transistor across the antenna path.
>
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