[Elecraft] K3: PRE/ATT Bug or feature?

[Bill K9YEQ]

Agreed!!! The preamp creates the amplification of incoming noise. Adding an
attenuator after the preamp makes little sense. 

I do not use the preamp unless the noise floor is low.  I use the ATT  when
the noise is high without the Preamp.  Really helps pull sigs in.  Forget
the S meter readings other than to help you decide on how to use the ATT and
Preamp settings....  This helps the dynamic range.  I would rather listen to
a clean S7 signal than an S9 + without clarity.  Hope that makes sense.

Bill
K9YEQ

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of ab2tc
Sent: Wednesday, August 11, 2010 3:50 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3: PRE/ATT Bug or feature?


Oof. Having the attenuator and preamp on at the same time is completely
nonsensical. The gain of the preamp is ~11 dB and the loss of the attenuator
is ~10dB so they almost completely cancel each other out gainwise. But *all*
the noise from the preamp will be added, so your noise floor will be
significantly raised and there is *no* advantage gained. The total dynamic
range will be reduced by at least the increase in the noise floor (that's
assuming that the preamp is completely distortion free).

AB2TC - Knut


The Smiths wrote:
> 
> 
> I find it to be much better in some circumstances.  I find that the 
> noise floor is actually reduced, not brought up by the 2dB that would 
> be expected.  This is very similar to when I adjust the RF Gain down 
> to about
> 3 o'clock.  Yet it works much faster because I can simply push the 
> button on and off when I need it.
>  
> <snip>
> 

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