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" <[email protected]> To: [email protected] 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 > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
