[Elecraft] K3 and preamp

[iain macdonnell - N6ML]

That doesn't justify a pre-amp. If you want more acoustic noise, just
turn up the AF gain. The only reason (I can see) to use a preamp is if
the receiver internal noise level is higher than the atmospheric noise
(coming from the antenna). If the noise level perceptibly drops when
you disconnect the antenna, a preamp isn't going to do much for
you....

73,

    ~iain / N6ML


On Fri, Sep 5, 2014 at 5:14 AM, Brian <alsopb at nc.rr.com> wrote:
> Quite some time ago there was a discussion that adding a preamp at the K3
> antenna terminals couldn't possibly help.  The argument is that it can't
> improve S/N
>
> Perhaps here is the reason it does help from somebody versed in ear/brain
> signal processing.
>
> 73 de Brian/K3KO
> --------------------
> On 8/28/2014 17:45, David McClain dbm at refined-audiometrics.com
> [FMT-nuts] wrote:
>> Some weeks ago I was musing about the way we all listen to the weak ones
>> on the HF bands.... And then it struck me, based on what I know about our
>> hearing:
>>
>> While we all dislike the constant rush of noise in the headphones, it
>> actually turns out to be helpful, and that's why we instinctively turn up
>> the volume and just live with the noise. When you do that, you are imposing
>> strong ambient noise on your hearing. That in turn affects the way your
>> hearing works. It produces a much steeper response to weak signals riding in
>> the noise. So a very small change in signal level causes a much larger
>> change in apparent loudness in your brain. It makes it easier to read the
>> weak signals.
>>
>> Coupled with that, we also need that noise to produce something called
>> "stochastic resonance", which is the basis for dithered noise added to
>> recordings. It lets you hear things that are solidly below the noise floor.
>>
>> - 73 de Dave, N7AIG
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