[Elecraft] K3 noise-blanker

[Art]

I hope this note proves useful for someone. Like many here my receiver 
career extends back through luminaries like the ARC5, Knight R100, 
Hallicrafters S22 etc. These were not only the main receiver, they were 
the only receiver in days when many of us scrounged a station that took 
more than a desktop to generate 50 watts. I used to operate phone but 
gave it up for less obstreperous pastures, so most of my recent 
experience (25 years or so) is CW and a bit of digital. As a matter of 
preference I began to concentrate on low-band DXing especially 80 and 160.

In days gone by it was necessary to ride three controls continuously: 1. 
RF gain. 2. AF gain. 3. VFO. Not necessarily in that order, and whatever 
you do don't jiggle the table. Most of the time I had little use for the 
AGC's of the day. At least for lowband weak signal DXing still do not. 
It is true that AGC OFF can produce some acoustic surprises.

Moving on through the various Drake lines, TS930, IC-765 and IC-781 
riding the VFO was no longer necessary. However, the other two controls 
continued to produce excellent results.

Next, a couple years ago, came an Orion 1. On the Orion web I read 
remarks similar to some reviewed here. We no longer need RF gain, the 
AGC does it all. I read and applied all the techniques. Well, yes and 
no. To be sure the latest DSP rigs have some advantages. The signal 
processing is vastly improved. But is it no longer necessary to do what 
we've always done, ride the RF gain?

In my experience the answer is a resounding NO. Riding the RF gain 
benefits the Orion at least as much as it ever did the earlier non-DSP 
rigs. Throw in superlative noise reduction and noise blanking (relative 
to the earlier rigs, anyway) coupled with signal processing and we can 
now copy signals unobtainable in earlier years.

My bet is the K3 will be no different, when I get it running. We shall 
see but I bet there is a reason the K3 has an actual, no kidding RF Gain 
knob instead of a menu choice like the wishful-thinking Orion. 
Especially on the noisy low bands there's just no replacement for 
letting the brain decide where system gain should be.

I hope the K3 allows me to turn off AGC. Well, the second loop anyway.

73 Art
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Bruce W8FU wrote:
with the Orion II, to get the best performance you have to be ready to
 > readjust the RF gain fairly often to suit band conditions and received
 > signal strength in order to get the best signal-to-noise ratio. That does
 > not appear necessary with the K-3. And the noise reduction circuit in the