[Elecraft] [K3] RX Gain Calibration

[Don Wilhelm]

Travis,

The S-meter should not indicate anything with the antenna disconnected.  
You should be searching for the reason the AGC is being activated on 
receiver noise - or it could be S-meter calibration.  The XG3 can allow 
you to properly calibrate the S-meter - the Utility program will guide you.

73,
Don W3FPR
On 3/19/2013 8:34 PM, Travis Brown wrote:
> Hi Don,
>
>   I agree 100%!   The S-Meter isn't as big of a concern to me as the fact that the noise floor seems to be so much more prevalent on the K3 than the KX3. I do understand that the more sensitive receiver will dip deeper into the noise floor and you will hear more of it.  If I always have to turn down the RF gain though, and the S-Meter shows something even when their is no antenna attached, I think it is worth it to calibrate things.  It's not like me to read manual, but so far, I have a pretty good track record of reading everything Elecraft sends me from cover to cover :)
>
> 73,
> Travis K2NP
>
> On Mar 19, 2013, at 8:12 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>
>> Travis,
>>
>> The real measure of any receiver in the ability to hear weak signals is not in the S-meter deflection.  Within limits both the K3 and KX3 S-meters can be calibrated to read most anything you want to see.
>> The measurement of actual sensitivity is in the MDS measurement. That indicates how weak a signal can be heard at 3 dB above the receiver noise floor.
>> When you get your XG3, I encourage you to follow the instructions in the XG3 manual for determining the MDS of a receiver.  With the XG3, that is a number inferred by the response at -107 dBm rather than a measurement using a well shielded signal generator and switching in attenuation, but the approximation should be within 1 dB of the actual MDS if you do the procedure (and math) as instructed.
>>
>> 73,
>> Don W3FPR
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>