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See also K2 Howling Fix

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Reply-To: "Indy" <kt5x at cnsp.com>
From: "Indy" <kt5x at cnsp.com>
To: <elecraft at mailman.qth.net>
Date: Tue, 18 Mar 2003 09:06:08 -0700
Subject: [Elecraft] EXTREME signals

It is so difficult to use language in such a way as to be absolutely =
clear to everyone.  let me try agn.

Wayne's back-to-back diode mod across the IF has absolutely no negative =
impact upon the radio.  The diodes do not conduct until an extremely =
strong signal is present.  When such is present, the diodes bleed off =
the excess signal to ground.

the result:  Under normal receiving, one will not know the mod has been =
done.  In the extraordinary case that a nearby station, for example, QRP =
to the field, four guys have their QRP radios set up near each other, if =
you tune across one, that signal will sound no different than any other =
S-9 signal.  However, when you tune off of that nearby signal, the AGC =
will be pumping with the keying of that extremely strong nearby signal.

In my test, I was keying a 100 watt station a few INCHES away from the =
K2.  I could tune across that signal with impunity, but if I was ten khz =
away, the K2 would pump with the keying of that 100 watt adjacent =
station making copy of a weak signal impossible, though I could copy a =
strong signal that would impact the AGC anyway.

However, if the MP were at five watts, a few khz away there was no =
longer any pumping ;-)

If you take your radio to field day and accidently tune across one of =
the other stations there, you would be glad to have the mod installed =
;-)

73,

Fred

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From: "Ken Wagner" <kewagner at ids.net>
To: "Dave" <dave at astromag.co.uk>
Cc: <Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] EXTREME signals
Date: Tue, 18 Mar 2003 12:33:30 -0500

To quote from Wayne's write up on this item...
quote
Results:
With the diodes in place, we've been able to transmit at 100 watts into an
antenna just a few feet from the K2's own antenna with no apparent K2
receiver degredation. In these tests the receiving antenna was non resonant.
But at the lower power levels used for HF pack operationa, there should be
no problem even with resonant antennas operating in each other's near field.
end quote

73, Ken K3IU

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