[Elecraft] Using K3's Pre-amp
Don Wilhelm
w3fpr at embarqmail.com
Sat Jan 10 06:49:25 EST 2009
Dave,
Whether you need the preamp will depend on your antenna.
Without involving any numbers, a quick test is to disconnect and then
reconnect the antenna. If the noise level increases when the antenna is
connected, the radio has ample front end gain (in fact it may be too
much - try it with the attenuator in too).
Your noise level does seem very high, so as Wayne suggested, you may
want to try a low gain directional receiving antenna should you want to
work the weak ones. There was one featured in QST for December 2008.
Alternately, snoop out the neighborhood for the noise source and fix it
if you can.
73,
Don W3FPR
Dave Yarnes wrote:
> I'm just curious how others are using (or not using) the K3's pre-amp. I
> have found few, if any, situations where I felt the pre-amp really improved
> a signal vs. the additional noise that is associated with turning on the
> pre-amp. It takes a lot of balancing, in my view, between the RF gain and
> the AF gain to enhance a weaker signal, and I don't find the pre-amp to be
> all that helpful. Having said that, I'm pretty happy with the results I get
> w/o using the pre-amp. Also, signals on the K3 w/o pre-amp compare very
> favorably to signals on my Orion II with the pre-amp on. The K3 still seems
> to hear just a tad bit better. So, I'm wondering if I'm missing some other
> trick or setting that would make the K3's pre-amp more beneficial. I can
> tell you that 90% or more of the time I tend to have my RF gain at 50% or
> less (at about 12 o'clock), and make very slight adjustments of the RF gain
> from there. I suppose much of this might depend on one's noise floor.
> FWIW, mine is about S4.
>
> Dave W7AQK
>
>
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