[Elecraft] I.F. Alignment

[Kevin Cozens]

At 11:44 PM 03/17/2003 +1100, David Walker wrote:
>Does anyone have a better way of align the IF.  I find the procedure of 
>tuning to the birdie near 7000khz a bit tricky.  I don't here much 
>difference as I turn the slug.  The actual peak is hard to detect.

I put out a message on the K2 list some time ago that one technique I came 
up with was to use Spectogram to monitor the birdie while adjusting L34. It 
makes it much easier to know when you have peaked the signal. Here is a 
copy of that message.


Date: Thu, 24 Oct 2002 01:34:50 -0400

At 02:10 PM 10/03/2002 -0400, someone wrote:
>There appear to be several methods to tune L34. Two that I am familiar with
>are:

There is a third method I discovered. I have mentioned it on this list but 
haven't gotten around to writing down the procedure until now. You can call 
it method 0.5 if you like since I came up with it before method 1 and 2 you 
mentioned. :-)

The procedure requires a computer capable of running the Spectogram 
program. In general, the procedure is as follows:

Set up your K2 and computer as if you are getting ready to align the 
filters. The main difference is that you need to tune the K2 so that you 
can hear the birdie on the 40m band (usually found near 7MHz).

Start with the slug in L34 near the top of the can. Turn the slug of L34 
clockwise to lower it in to the can. As you do this you should see the 
strength (height of the birdie as seen on the Spectogram display) increase. 
Stop when you reach the point at which additional turning of the slug in 
L34 do not cause any further increase to the signal as seen in the 
Spectogram display.

Turning the slug in L34 past the point at which no increase in signal 
strength is observed will just result in an increase in noise. It was 
reported on the Elecraft mailing list that the best signal to noise setting 
for L34 may be about 1/4 to 1/2 turn BEFORE you reach the point of maximum 
signal.

This is not the only procedure for adjusting the slug in L34 but this 
should help make it easier than adjusting by ear alone.

Don't forget to re-run CAL S Hi/Lo after making any adjustment to L34.



Cheers!

Kevin.  (http://www.interlog.com/~kcozens/)

Owner of Elecraft K2 #2172        |"What are we going to do today, Borg?"
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