03 September 2014

The best AGC setting for weakest lowbands sigs pickup on Elecraft K3


as I am lowbands enthusiast and the Elecraft K3 transceiver owner also... I am interresting in any kind tools, h/w as same as K3 setting how to pick up the very weak CW signals on the lowbands (160/80/60/40m).

I started to play with wide variety of AGC system setting in my K3 and I am currious which kind of setting is used on K3 by other users...

The links and sources which I already visited (documents for study/research):


In fact I used for long time the AGC off in cases of pulling weakest sigs out of the noise but specially in pile-up it was really danger when the strong sigs attack my ears.

For that reason I would like to use all of opportunities of AGC system in K3 with proper setting. So I will be happy for any kind of settings hints and experiences for CW weak sigs handling.

I am trying to play with the AGC system setting in order to optimize to my needs (weakest CW sigs on lowbands). I am sure that it will be different from other users also because of my local background noise/noise floor environment, disturbation and other noise sources...

My original setting was for years as follows:

AFV TIM: 1000 / AGC DCY: NOR / AGC HLD: 0.00 / AGC PLS: NOR / AGC SLP: 14 / AGC THR: 3 / AGC F/S: 120/20

... but it sounded so noisy and I commonly turned AGC off in order to get quieter RX for weak sigs. Of course that I was attacked by strong sigs in pile-ups or contests and I was punished when AGC was off.

After some discussion on Elecraft reflector I got few recommendations from which I finally decided to try this config:

AFV TIM: 1000 / AGC DCY: SOFT / AGC HLD: 0.20 / AGC PLS: NOR / AGC SLP: 000 / AGC THR: 8 / AGC F/S: 200/20

... which was recommended by several users for weak CW signals reception. (many thanks to Merv, K9FD/KH6)

I found very quickly that the receiver appeared a bit noisy so I added N1EU pink noise roll-off on RX EQ.

I used the left side red column settings:

http://n1eu.com/K3/K3_notes.htm (many thanks to Adrian, VK4TUX)

It helped I guess but I realized that the behavior of AGC in my K3 with this setting is in general not what I am looking for and I do not like it so much. The improvement is that when there is no signal on frequency then this setting of AGC sounds more quiet than AGC off for now! 
Unfortunately I do not like the "slow pumping" of AGC which is pulling down the receiver gain some time...

So I am looking for another settings or ideas and I am going to make more research.

73 - Petr, OK1RP

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