[Elecraft] Attenuator and RF Gain Settings

[Joe Subich, W4TV]

> I wish I could set it higher than 008. I am also in a 
> relatively quiet location but on 20m with an AGC threshold of 
> 008 my atmospheric noise is normally above the AGC threshold. 

If one looks at Jack Smith's graphs, the K2 threshold (between 
-80 and -90 dBm) would be about 11 or 12 for the K3 and the 
slope is about 5 or 6.  Jack's measurements show that even at 
8, the K3's AGC threshold (onset of AGC) is down around -100dBm.  

Sherwood shows the K3's AGC threshold at 2.1 uV vs. 10 uV (no 
preamp) for the K2 and .6uV vs. 1.7 uV with the preamp.  I 
find it interesting that Sherwood's measurements of the 
FT-1000D (6 uV) and FT-1000MP MK V (3 uV) also show higher 
AGC thresholds with the preamplifier on.    

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of ab2tc
> Sent: Tuesday, February 02, 2010 5:08 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Attenuator and RF Gain Settings
> 
> 
> 
> Hi,
> 
> I wish I could set it higher than 008. I am also in a 
> relatively quiet location but on 20m with an AGC threshold of 
> 008 my atmospheric noise is normally above the AGC threshold. 
> So when I want comfortable listening I back off the RF gain 
> until the S-meter shows about S4 or so. Not a big problem, 
> but I would prefer that the AGC threshold could go higher. 
> Having it stored per-band, too, would be really, really nice 
> and it makes sense.
> 
> Knut - AQB2TC
> 
> 
> Don Wilhelm-4 wrote:
> > 
> > I just thought of something that might help those confused 
> by the AGC
> > Threshold setting.
> > One other way to look at the required AGC Threshold level 
> is to think of 
> > it as an S-meter level
> > If your noise is S-1 or lower (on the K3's S-meter), you 
> can set the 
> > Threshold to 002 or higher and all may be well
> > OTOH, if you have an S-7 noise level indicated, the AGC 
> Threshold should 
> > be set to 008 or higher.
> > <snip>
> > 
> 
> -- 
> View this message in context: 
> http://n2.nabble.com/Attenuator-and-RF-Gain-Settings-tp4503505
p4504035.html
Sent from the Elecraft mailing list archive at Nabble.com.
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