[Elecraft] Need help tracing signal

[John R. Lonigro]

Tom wrote:

>
>The troubleshooting section of the manual tells us how to build a RF probe,
>which I did.  It seems to work fairly well, but this raises my first
>question.  Can I use the probe that came with my oscilloscope?  I like the
>idea of using the DMM as it is easier for me to read than the scope.
>  
>
The scope and its probe will show waveforms, not just voltages, which 
might be more enlightening.  The RF probe that came with the K2 is for 
us poor slobs who don't own a decent scope.  Either should work, but if 
you have a scope, go for it.

>
>What I do have is the Ft. Smith Marker/Generator, which puts out a signal
>every 5 kHz including (I suppose) 10 MHz.  When I measure this signal with
>the RF probe which I built, its reading well over 2 Vrms.  The K2's
>troubleshooting section is talking in the 0.14 Vrms range.  So I have much
>more output than is called for.
>
>So, dear gurus, what do I do?  I can breadboard the K2's suggested signal
>generator and use a bunch of fix resistors in series and parallel (that
>sounds kind of crazy).  Or can I put a fixed resistor in series with the
>output of the Marker/Generator and then use a pot that I have, in the 25K
>range, to get the output down to 0.14 Vrms or so. (Oh, and it calls for a
>non-inductive pot - how do I tell that?)
>  
>

A non-inductive pot is one that is not wirewound.  Most volume  or tone 
controls from old radios are typically non-inductive.  I believe the 
pots Radio Shack sells are suitable.

>Or, can I just use the marker/generator as is with the 2.x Vrms and adjust
>my expected readings through the receiver accordingly (this seems to be the
>easiest).
>  
>
I would NOT pump 2.x Volts rms into the front end of any radio.  The 
Elecraft manual states that the receiver output resulting from the .14 
Volt injected signal "might be quite strong even if your receiver is 
attenuating the signal somewhere."  Just think how strong it would be if 
you injected 2.x volts into the front end and the receiver weren't 
attenuating the signal somewhere!

>I appreciate your help, I don't think I've ever come away from this list
>without a satisfactory answer to whatever I've asked (except maybe when I
>asked to be bumped up on the list for shipping my DSP module).
>
>Thanks in advance
>
>Tom
>WB2QDG
>K2 s/n 1103
>
>
>_________________________________
>I may run qrp but I've got a Higher Power!
>
>
>
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>  
>