No argument with the theory here, though my personal experience is not consistent with the earlier observation that a preamp won¹t do much if the noise level drops perceptibly when the antenna is disconnected. On my K3 on 10M the noise level drops when no antenna is connected (by 10dB? Maybe not); AND the PR6-10 preamp improves the readability of very weak signals when it is in the circuit compared to when it is not. If that¹s just a placebo effect, I¹ll take it.
I received a couple of off-list comments that might be of interest to those who are following this thread. One was that narrowing the BW also improves the S/N. That is quite true - indeed, BW narrowing in the K3 is generally better, in my circumstances, than the K3¹s on-board NB and NR facilities are (though I confess I have much to learn about those.) Another comment was that I must have a very RF-quiet location. Perhaps so: The station QTH is in a part of Teller County with single family / 35 acre zoning, which puts the nearest neighbor some 1,500¹ away; and my power line is buried under 8¹ of decomposed granite on its final 200¹ to the house. That, to be fair, is consistent with Jim¹s and Iain¹s observations that the preamp works by raising the signal AND noise above the receiver¹s internal noise. Ted, KN1CBR . . >Message: 6 >Date: Fri, 05 Sep 2014 14:25:27 -0700 >From: Jim Brown <[email protected]> >To: [email protected] >Subject: Re: [Elecraft] K3 and Preamp >Message-ID: <[email protected]> >Content-Type: text/plain; charset=utf-8; format=flowed > >On Fri,9/5/2014 2:08 PM, iain macdonnell - N6ML wrote: >> I didn't say that the pre-amp isn't worth the money - I just said that >> supplying more noise to the ears isn't a good justification for it. >> It's well known that the K3 needs a pre-amp for effective weak-signal >> work on the higher bands, but it's not (primarily) because it makes >> the noise louder - it's because it raises the signals (from the >> antenna) above the receiver's internal noise. > >Exactly. > >73, Jim K9YC ______________________________________________________________ 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]
