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K3 antenna bleed thru

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Mike Reublin NF4L

K3 antenna bleed thru

I was helping a friend with his remote setup. We were on 20M CW, and I copied him about an S5. He couldn't hear me at all (both 100W).

Later I realized I was on ANT 2. Why was I able to hear him so well? Do I have a problem?

73, Mike NF4L
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Mike Reublin NF4L

Re: K3 antenna bleed thru

There is nothing connected to ANT 2.

> On Mar 13, 2015, at 09:17, Mike Reublin NF4L <[hidden email]> wrote:
>
> I was helping a friend with his remote setup. We were on 20M CW, and I copied him about an S5. He couldn't hear me at all (both 100W).
>
> Later I realized I was on ANT 2. Why was I able to hear him so well? Do I have a problem?
>
> 73, Mike NF4L
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Richard Ferch

Re: K3 antenna bleed thru

In reply to this post by Mike Reublin NF4L

NF4L wrote:

> I was helping a friend with his remote setup. We were on 20M CW, and I copied
> him about an S5. He couldn't hear me at all (both 100W).
>
> Later I realized I was on ANT 2. Why was I able to hear him so well? Do I have
> a problem?

Well, suppose the isolation between ANT1 and ANT2 is 50 dB. A signal
from your friend that would have been 30 dB over S9 on ANT1 would show
up at S5 or S6 on ANT2 due to the -50 dB bleedthrough.

In the other direction, you were transmitting into a high SWR. To
protect itself the transmitter would have folded power back to some low
level, and on top of that there would still be the 50 dB of isolation
between the transmitter and your antenna, so perhaps it's not so
surprising he couldn't hear you even though you could hear him.

73,
Rich VE3KI
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Oliver Dröse

Re: K3 antenna bleed thru

In reply to this post by Mike Reublin NF4L

Mike,

relay isolation between ANT1 and ANT2 is not too good (in the order of
30-40 dB max if I remember correctly, measured it a few years ago). That
means even if you have selected ANT2 but do not have anything connected
to ANT2 you might still hear signals from ANT1 if they are strong enough.

73, Olli - DH8BQA

Contest, DX & radio projects: http://www.dh8bqa.de

Am 13.03.2015 um 14:17 schrieb Mike Reublin NF4L:

> I was helping a friend with his remote setup. We were on 20M CW, and I copied him about an S5. He couldn't hear me at all (both 100W).
>
> Later I realized I was on ANT 2. Why was I able to hear him so well? Do I have a problem?
>
> 73, Mike NF4L
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>