[Elecraft] sensitivity/noise question

[Hisashi T Fujinaka]

I asked Tom if I could forward his reply back to the list so it could be
archived. He said it was OK, so here it is!

I didn't know the K2 had a lot less background noise and I forgot to
mention that I know that S-meters are often quite arbitrarily set up.

-- 
Hisashi T Fujinaka - htodd at twofifty.com
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte

---------- Forwarded message ----------
Date: Thu, 22 Jul 2004 06:53:09 -0500
From: Tom Hammond <n0ss at earthlink.net>
To: Hisashi T Fujinaka <htodd at twofifty.com>
Subject: Re: [Elecraft] sensitivity/noise question

Hello Hisashi:

> Compared to my IC-706MKII, the Elecraft seems to be stingier on the
> S-meter and seems to hear a lot less noise. And yes, I used an antenna
> switch and did A/B comparisons.
> 
> I shouldn't complain, since the Elecraft is great to listen to,
> especially on 40M, but should I break out the test equipment and try to
> peak things up again?
> 
> And now that I type this, I wonder if my cabling is OK.

I think the question is whether the K2 is hearing everything the IC-706 is, and 
whether it's hearing it BETTER as well.

The K2 is NOTED for its low-noise front end and the fact that it is generally 
MUCH(!) QUIETER than just about ANY other receiver... even the high-dollar 
models. You should NEVER expect (or hope) to hear as much noise in the K2 as 
you will hear in the other rigs. BUT, you should hear the SIGNALS better, and 
with less background noise.

For me, the S-meter is nothing more than a relative indicator of signal 
strength, so 'accuracy' of the represented signal level has never been a 
problem at all... especially since most users will use the Preamp on some bands 
and not on others... this tends to blow the idea of 'accuracy' out of the 
water.

For what you have written, above, I would say that you have things set up just 
fine.

There is a procedure to adjusting L34 for the best signal-to-noise ratio. This 
procedure has not been published yet, but will appear on my web site soon.

...

Since you have already aligned your xtal. filters, you 
will only want to consider the first few steps of the procedure... the part 
which sets up Spectrogram and then adjusts L34 for best S/N ratio. Here, I 
small, weak (perhaps 1uV or so) injected signal on 40M, with NO antenna 
connected will work well to provide a signal which can be used to compare 
against the internally-generated noise of the K2 when adjusting L34 for best 
S/N ratio.

Good luck, and HAVE FUN!

73,

Tom Hammond    N0SS