Here's another feature available on all of our newer radios: the AF limiter. 


Background
----------

AGC (automatic gain control) keeps the AF output level of a receiver relatively 
constant over a wide range of RF input levels. Most operators keep their 
receiver's AGC on at all times, so there's no need to "ride" the RF gain 
control.

However, some operators prefer to turn AGC off. When AGC is off, you experience 
the full dynamic range of received signals, which can help separate signals 
from each other, or just provide a more "lively" receiver sound completely free 
of gain adjustments. But in this case you *do* need to manually adjust RF GAIN 
to keep signals in a comfortable range.

The problem with this operating style is that extra-large signals can pop up 
unexpectedly. You might not be able to manually react fast enough to keep them 
in a comfortable range. This is the reason for the AF limiter. 


Setting Up the AF Limiter
-------------------------

The AF limiter is set using CONFIG:AF LIM (K3/K3S) or MENU:AF LIM (KX3/KX2). 
The default value is "NOR" (normal), which puts the limit threshold very high 
-- around the point where the AF amplifier chain itself would cause limiting 
(extremely loud). So if you plan to turn AGC off, you'll need to set AF LIM 
lower. 

A good approach is to start with AF LIM = 23. Then turn off AGC (see below), 
and see if you feel that the limiter needs to come on at a weaker signal level 
(lower number), or stronger (higher number). The manual recommends a range of 
17 to 23.


Turning AGC Off
---------------

- On the K3 or K3S, hold the AGC switch (the yellow label is "OFF"). 

- On the KX3 or KX2, set MENU:AGC MD to OFF.

In both cases, this will change the AGC icon from "AGC-S" or "AGC-F" (AGC on, 
Slow or Fast) to "AGC-" (AGC off).

With AGC off, be prepared to adjust the RF GAIN control, and don't forget to 
adjust the AF LIM value as described above.


73,
Wayne
N6KR


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Reply via email to