[Elecraft] K3: RF Gain, Squelch

[David Y.]

Don and All,

Your last post raises a question in my mind--it probably has been discussed 
before, and if so, I missed it.  I must admit that the number of posts on 
this reflector is often overwhelming, and I'm sure I get too quick with the 
delete key.

Here's the question--I bought the 6 khz filter, but not the 13 khz filter. 
I don't do AM, and probably won't do much, if any FM, but I suppose the 
possibility is there for a very small amount of FM on 10 meters perhaps. 
Anyway, I bought the 6 khz filter, primarily to accomodate any SW listening 
I might do.  So, would I have been better off to buy the 13 khz filter 
instead of the 6 khz filter?  That sounds like what you did.  I assume I 
could just use the 13 khz filter for AM listening, and use the DSP to narrow 
things appropriately.  I wouldn't have a 6 khz roofing filter, but would I 
really be at much of a disadvantage for the type of use I describe above? 
For some reason, I thought the 6 khz filter was mandatory for AM, but maybe 
I misread that (or misinterpreted what I think I read!).

By the way, your discussion of how to set the RF gain makes a great deal of 
sense to me.  It is, in fact, what I have been doing intuitively.  My RF 
gain is almost always set at something like 12 o'clock or so--maybe a tad 
bit higher.  My "excursion range" with the RF gain rarely goes beyond the 2 
o'clock position, even on very weak signals.  Beyond that all I seem to be 
doing is increasing the noise level with little or no improvement in the 
desired signal.  I rarely use the preamp, and find that it more often than 
not degrades what I am trying to hear.

Dave W7AQK


----- Original Message ----- 
From: "Don Wilhelm" <w3fpr at embarqmail.com>
To: <n1al at cds1.net>
Cc: "Elecraft Discussion List" <Elecraft at mailman.qth.net>
Sent: Monday, January 11, 2010 10:10 PM
Subject: Re: [Elecraft] K3: RF Gain, Squelch


> Al,
>
> To look at it another way - look at the S-meter to observe the band
> noise level, and then back off the RF gain until the S-meter is steady
> at that same S-meter reading.  Of course, this should be done at a spot
> in the band where no signals are present.
>
> That is a quick way to determine the optimum setting for the RF Gain
> consistent with the greatest receiver dynamic range and one does not
> have to listen to the constant band noise clutter.
>
> The other option is to just run with "all knobs full right" and put up
> with listening to the band noise when there are gaps in the signal level.
>
> Be aware that the AGC Threshold will also have a great effect on the
> amount of band noise heard in the audio.  If the Threshold is set too
> low, the receiver will go into AGC action on only the band noise.  I use
> an AGC Threshold setting of 008 just for that reason (I know the default
> is 005, but I think that is too low).
>
> 73,
> Don W3FPR
>