[Elecraft] IF tap?

Tue Jan 3 12:03:17 EST 2012

Steve,

Installing a buffer amp such as the Clifton Labs Z10000 - K2 is the 
"cleanest" solution, but there is an alternative if you are just playing :-)

Depending on the level of the natural noise floor of your Spectrum Analyzer 
and the interconnecting coax's capacitance, the IF signal at the emitter of 
the post-mixer amp Q22 might be strong enough to drive the Spectrum 
Analyzer. To avoid "upsetting" the post-mixer amp, you would have to connect 
your Analyzer's "hot" input to Q22's emitter via a R and C in series.  I 
suggest that the value of the added capacitor be 10nF, and that the value of 
the added R be not less than 470 ohms.

The function of the added capacitor is only to prevent any DC from the K2 
reaching your Spectrum Analyzer.

The shield of the coax at the post-mixer amp end should be grounded using 
the same pad (if possible) which is used to ground one side of C162.

Have fun!

73,
Geoff
LX2AO

----- Original Message ----- 
From: "Steve KC8QVO" <kc8qvo at yahoo.com>
To: <elecraft at mailman.qth.net>
Sent: Monday, January 02, 2012 11:35 PM
Subject: Re: [Elecraft] IF tap?

>
> Don Wilhelm-4 wrote
>>
>> Steve,
>>
>> This Elecraft email reflector stopped being the K2 reflector as soon as
>> the K1 was available, and now there are questions about the K3, K2, K1,
>> KX1, now the KX3, KPA500, KRC2, mini-modules, and any other product that
>> Elecraft has produced or has announced for the future.
>>
>> Clifton Labs Z10000-K2 buffer can be installed in the K2 to provide
>> IFoutput for your spectrum analyzer.  Look at
>> http://www.cliftonlaboratories.com/z10000_buffer_amp.htm.
>>
>> 73,
>> Don W3FPR
>>
>
> In regards to the reflector/forum - I posted on the website under the K2
> forum. There are also categories for the K1, KX1, K3, etc. I am not using
> the e-mail system to get the post in to the reflector. I forgot that the
> e-mail list does not "categorize" posts in the same regard that the 
> website
> does for the reflector.
>
> Just playing around here - I dug out my manual and found the RX Mixer. I
> tapped the Post-Mixer Amp side of C159 and the ground side of R80 with a
> length of RG-174. Then I ran that back to the receive antenna connector on
> the 160 module (desoldered the wires to the 160 module). I figured this
> would give me a 4.915mHz reference from which to tap but it doesn't work 
> too
> well. There's more to learn here for sure.
>
> I figured there would be a place in the circuit I could tap to bring out 
> the
> IF to the analyzer. Would I not be correct in assuming that the spectrum
> analyzer can read the same signal(s) fed to the rest of the K2's receiver?
>
>
> --
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> Sent from the Elecraft mailing list archive at Nabble.com.
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