[Elecraft] K2 : Is this ok for AGC threshold??

[Fred Bennett N9TA]

  Thanks for the quick reply Don !!!

I guess I will continue then.....I'd decided to stop further 
construction until I had an answer. Just in case it was something to be 
concerned about.

Gosh....seems like these components just get smaller and smaller....HI HI

               73...de...Fred  N9TA
_______________________________________________


Don Wilhelm wrote:
> Fred,
>
> It is all relative.  If the 8 volt regulator output is on the lower 
> side of its spec (it is a 10% tolerance part), then everything will 
> work out just fine, set it to the maximum.
> Reason - the IF amplifier is the stage controlled by the AGC, *and* it 
> is powered by the 8 volt regulator.  When the IF Amp supply voltage is 
> reduced, the ACG action begins at a lower voltage point than at higher 
> voltages.
>
> Bottom line - if you are able to set the S-meter parameters with the 
> lower AGC Threshold voltage, then all is well.  If you cannnot adjust 
> the S-meter, then a 10k to 15k resistor soldered across pins 3 and 4 
> of Control Board RP6 will allow you to adjust the threshold upward.
>
> Yes, a manual errata sheet should be published IMHO.  The 3.8 volts is 
> not graven in stone.  There is an implication in the K2 manual that 
> the AGC threshold can be optimized later on, but there are no details 
> of how to do that - in fact, that optimization is simply reducing the 
> AGC Threshold voltage so that receiver noise does not activate the AGC.
>
> 73,
> Don W3FPR
>
> Fred Bennett N9TA wrote:
>>    Hi Gang
>>
>> Construction on my 3rd K2 is coming right along......BUT....I have a 
>> question: I'm at page 48 of the manual where I am going through the 
>> first power-up checks. I can't get the "AGC Threshold" voltage up to 
>> 3.8 Vdc as suggested. My new K2 tops out around 3.62 as measured with 
>> a Square D WMM-23 digital multimeter. Is this something I should 
>> worry about??
>>
>>                          73....de....Fred  N9TA                   K2 
>> serial# 6705 under construction
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