[Elecraft] Simple way to set L34

[Jim W7RY]

I find a very definite "peak" indicated minimum voltage at
one spot in the L34 adjustment.

I think the word you were looking to replace the "Ronism" is......Dip.. :)

But the Ronism' version was good toooo..

Thanks for the info Ron!
73
Jim W7RY


----- Original Message ----- 
From: "Ron D'Eau Claire" <rondec@easystreet.com>
To: <elecraft@mailman.qth.net>
Sent: Sunday, September 29, 2002 5:38 PM
Subject: [Elecraft] Simple way to set L34


> Gary Surrency posted a message here a year or so ago about setting L4
> using a DMM rather than by "ear". Of course I lost it, but the next time
> I wanted to check the setting I recreated my own version of it (might
> even be the same) by remembering is general approach.
> 
> The procedure is to tune the 7 MHz "birdie" and adjust L34 for maximum
> AGC voltage. Since the AGC voltage is a function of the amount of signal
> coming out of the IF amplifier, that assures you that L34 is on its
> "peak". 
> 
> I connect the DMM to the "hot" end of R2 on the Control Board. The
> Control board is the one attached to the front panel assembly that faces
> toward the inside of the K2. Looking down onto the board from the top
> with the cover removed, R2 is right next to U2 on the right end of the
> board near the top edge. The end of R2 nearest the top of the board is
> grounded. You must connect  the test probe to the end of R2 furthest
> from the top edge of the board. Be sure you don't short to the adjacent
> component leads. 
> 
> Connect a dummy load to the rig. You must avoid picking up any outside
> signals or noise. They will mask the reading. 
> 
> Turn the K2 On.
> 
> Turn the preamp On. 
> 
> Ensure the AGC is On
> 
> Set RF Gain at maximum (fully clockwise).
> 
> Tune in the 7 MHz "birdie". Use SPOT to be sure that you have it right
> on frequency. 
> 
> Now adjust L34 for MINIMUM voltage on the DMM. The setting is a bit
> broad, but I find a very definite "peak" indicated minimum voltage at
> one spot in the L34 adjustment.
> 
> A DMM is required because the change in voltage is only a few hundredths
> of a volt with a little over 3 volts to ground.  In mine the voltage
> sits at about 3.646 on the "sweet spot" rising to 3.647 or 3.648 1/8 to
> 1/4 turn off of the "peak" in either direction. 
> 
> That does it for me. 
> 
> Ron AC7AC
> K2 # 1289
> 
> ===============================================
>  no9e wrote:
> >2. After doing 2nd XTAL mod, the sensitivity with FL2-4 is about 10 db
> >lower than with F1. Also, I feel that the CW sensitivity is lower. I 
> >peaked L34 but the peak was not too sharp. Does the modification
> (inluding 
> >removal of 10p), deteriorate CW sensitivity? I used BC337 instead of
> PN2222.
> 
> kevin wrote:
> Finding the point of maximum signal with least noise is not an easy
> thing 
> to do by ear alone. There is no sharp peak as you have found. I have a 
> procedure for setting L34 using Spectogram but I haven't written it up
> yet. 
> Its on my list of things to be done however. Hopefully soon.
> 
> _______________________________________________
> Elecraft mailing list: Elecraft@mailman.qth.net
> You must be a list member to post to the list. 
> Postings must be plain text (no HTML or attachments). 
> See: http://mailman.qth.net/mailman/listinfo/elecraft
> Elecraft Web Page: http://www.elecraft.com
>