[Elecraft] K3 and Preamp

[Dauer, Edward]

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 <jim at audiosystemsgroup.com>
>To: elecraft at mailman.qth.net
>Subject: Re: [Elecraft] K3 and Preamp
>Message-ID: <540A2A47.4030206 at audiosystemsgroup.com>
>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