Jack,
If by "mistune" you mean that the impedance will be loaded down, yes
that is likely. A buffer amp following will solve that . My reply
was merely to indicate tapping the 1st IF at W3 is a good
decision. I run both main Rx IF and sub Rx IF to LP-Pan that have
the optional IF amps installed (now std in the LP-Pan 2). Both
appear to work fine bringing out the 1st IF to my LP-Pan which in
turn provide IQ baseband input to a four port soundcard for diversity
reception on 2m-eme (a special application using digital modes).
I did determine that feeding the 1st IF to the 2nd IF of the K3
loaded the panoramic display at frequency zero, so I select a xtal
location that is unfilled to effectively disconnect the 2nd IF. But
normal use of the K3 using the entire receivers works fine. I do not
detect any loading of the 1st IF by either LP-Pan.
Now probably one should use a 0.01uF cap instead of 0.001uF for 8.215
MHz. That will provide a little more RF coupling.
One other item I did omit is the use of a ferrite on the RG-174 for
isolating the shield for any noise introduction to the IF.
73, Ed - KL7UW
From: wa9fvp <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Sub Receiver I.F. Tap
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Edward R Cole wrote ;
I brought out the 1st IF of the sub receiver from that point using
0.001 uF disc ceramic coupling cap to RG-174 coax snaked out thru a
hole in the sub-Rx shield to a BNC on back panel of the K3.
-------------
I think that connecting the coax via a capacitor would load and mistune the
I.F.. That's why the main receiver was designed with a buffer JFET.
-----
Jack WA9FVP
73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[email protected]
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