[Elecraft] RX Ant K3 Preamp vs External Preamp

[donovanf at starpower.net]

A good rule of thumb is that if receiver background noise level drops at 
least one S-unit when the antenna is removed, then receiver sensitivity 
is externally noise limited. This may be hard to achieve on 6 meters 
unless all losses from the antenna feed point to the receiver input are less 
than 2 dB and impossible to achieve on 2 meters and above unless total 
losses are less than one dB. 


This rule-of-thumb is very valuable on the lower bands because it helps 
the operator select the proper receiver attenuator and RF preamplifier 
settings for optimum dynamic range while retaining full system sensitivity. 
You'd be surprised how few DXers and contesters understand this simple 
principle, and fewer still actually do it when they sit in front of their 
receiver. 


73 
Frank 
W3LPL 

----- Original Message -----

From: "Bob McGraw K4TAX" <rmcgraw at blomand.net> 
To: elecraft at mailman.qth.net 
Sent: Monday, April 27, 2020 12:12:56 AM 
Subject: Re: [Elecraft] RX Ant K3 Preamp vs External Preamp 

The internal preamp in my K3S does an excellent job on 6 meters. If I 
decided to use an external preamp, it would be located at the antenna 
feed point with suitable switching and protection. 

I suppose the question, what bands do you perceive you need a preamp? 
And what is your no signal band noise on the bands of concern? 

73 

Bob, K4TAX 


On 4/26/2020 6:32 PM, Rich wrote: 
> I am interested in finding out from the experts.................... 
> 
> Is it best to use the K3 internal pre-amp or add an external pre-amp 
> to the RX antenna system? 
> 
> Thanks 
> 
> Rich 
> 
> K3RWN 
> 
> 
> 
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