That sounds about right. With the preamp on the K3 is more sensitive so the noise level drops. With the attenuator on the K3 is less sensitive so the noise level rises.
Another way to look at it is to realize that the P3 compensates for the K3 attenuator and preamp to keep signal levels the same. So when you turn on the preamp, the P3 lowers its gain so that signals show at the same S level. That makes the noise look lower. Alan N1AL > K3+P3. when the K3 is set up into a dummy load, with the pre amp OFF. > the > noise base line is at S1/2 (between S0 & S1) on the P3. > Then switching in the ATT the noise floor climbs to S2, > With the ATT switched in and the PREAMP on, the noise floor goes back to > S1. > With just the Preamp On the noise floor goes to S0 > It does this on all bands > Is this right? or am I just nit-picky > > Ed K7WIA > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/P3-noise-floor-base-line-question-tp5997094p5997094.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
