[Elecraft] AGC Threshold Adjustment by Changing R1

[Mike Walkington]

Hi Bob,

 

I have an A model K2, so R1 was originally installed as a 51K.  I removed it
and put in a variable and determined on a quiet band, subjectively by ear,
where noise with AGC on and off seemed the same.  I got different readings
each time I did the test, but a mid 40k reading seemed to occur the most
often so I went with that.  Now trying to see what others got as I'm still
not 100% confident.

 

Mike

VK1KCK

K2 #2599 

 

  _____  

From: G3VVT at aol.com [mailto:G3VVT at aol.com] 
Sent: Thursday, 6 January 2005 9:45 PM
To: mike at walkingtons.com
Subject: Re: [Elecraft] AGC Threshold Adjustment by Changing R1 

 

Hi Mike,

 

In the latest revision of the K2 manual version F, 29 January 2004, R1 is
given as 50K preset. In the world outside the USA this would indeed equate
to 47K. The preset has one end strapped to the wiper so would be a
continuously variable resistor from in your case 47K down to zero which is
in series with the 5.1K in RP6. The preset apparently normally comes out at
somewhere near half rotation or in other words about 23 to 25K.

 

Believe the earlier versions of the K2 had a fixed resistor for R1 selected
on test (SOT). Not sure of the start value used, though there seemed to be
less emphasis on the adjustment then to what is current now to ensure AGC is
fully off with no signal.

 

Seems to have been a few reports recently with the resistor at one end
though they did not quote which end to know the value.

 

Regards,

Bob, G3VVT

K2 #4168