[Elecraft] L34 adjustment

Wed Oct 15 20:30:01 2003

Dear Floyd,

One of the K2's I built exhibited the same problem you are describing -
broad "peak with little or no sharp peak.

I found that I had misloaded C182.  Instead of 180 pF, I loaded 1800 pF.
There was no peak, and the overall receiver gain was lousy.  Turns out, some
of the marking paint had come off the numeral "2" in the "182" on the 1800
pF so it looked like 181, or 180 pF.  I swapped the correct parts and the
coil peaked right up.  As I recall, the 1 turn to 1 1/2 turns was about the
same in my unit as Don mentioned

I was using a signal injection technique where I inserted a signal of 4.915
MHz into the circuit at the diode switch D7 cathode.  I was able to have a
large sinewave to look at on the scope and also on the spectrum analyzer
when looking at pin 8 of U12.

I would sincerely suggest that you check the values of C182, C179 - mostly
C182.  Check the soldering in the pins of the capacitor and on the inductor.
Make sure U12 is installed correctly.  Using my measurement method, I got a
nice peaking of the signal and a lot more gain once the correct parts were
installed correctly!

Again, a broad "peakless" response really isn't normal.

Good luck,

Bill
NA7Y
----- Original Message ----- 
From: "Floyd Sense" <[email protected]>
To: "Elecraft" <[email protected]>
Sent: Wednesday, October 15, 2003 8:40 AM
Subject: [Elecraft] L34 adjustment

> When adjusting L34 on my K2, I found the peak to be very broad and not
very
> much of a peak at all.  The slug is a bit higher in the can than mentioned
> in the instructions.  Does that sound normal?
>
> K8AC
>
>
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