[Elecraft] Noisy K3 receiver

[Bill W4ZV]

Bill W4ZV wrote:
> 
> 
> 
> Ralph Parker wrote:
>> 
>> I'm used to leaving the RF gain wide open on the MkV, leaving the audio
>> gain pretty much alone, and maybe switching between SLOW and FAST
>> occasionally. I don't seem to have any trouble hearing the weak ones
>> under
>> the strong ones.
>> Now I have to fiddle with the RF gain (a small knob hidden amongst the
>> others) while running a pileup. Not enough hands (or enough brains).
>> 
> 
> If you set up your K3 as you described above, I guarantee you will have a
> noisy RX.  Furthermore, you are wasting the dynamic range of the K3 (or
> your MkV for that matter).  In a previous post I described how to set up
> the K3.  Once set up correctly, you should seldom need to touch either RF
> or AF gain during an entire contest and can simply let the K3's excellent
> AGC and dynamic range do the work for you.  IMHO good ergonomics doesn't
> mean having access to 24 knobs that need to be continually adjusted, it
> means not having to adjust them in the first place.
> 
> 73,  Bill  W4ZV
> 

Several have asked for more info about how to set up the K3 gain.  The
following is a simplified version of a comprehensive article by K3NA below:

http://wiki.contesting.com/index.php/Setting_receiver_gain_controls

Note that Eric's setup is for AGC Off, which is probably not a good idea for
most casual users.  I would start with AGC-F using the default AGC Menu
settings.  You can check the defaults for each CONFIG: AGC Menu by tapping
the DISP button while in the appropriate CONFIG Menu (all AGC settings begin
with CONFIG: AGC xxx, and remember that some are only accessible with
CONFIG: TECH MD On).

1.  Have available your desired antenna and a dummy load (both on a coax
switch is ideal) for each band you want to set up (you'll at least need to
do this for major segments like 80/160, 40-18, 15-10 and 6 separately (if
you have the external preamp).

2.  Set AF GAIN back to about 9 o'clock and RF GAIN to MAX (fully
clockwise).  This assumes you have the proper AF GAIN menu setting for your
specific headphones (I use AF GAIN - LO for my 32 ohm headphones and still
have tons of audio).

3.  In the following order (first ATT ON, then ATT OFF, then PRE ON)
alternately switch between your antenna and the dummy load.  When you hear
noise increase when switching to the antenna, use the lowest gain setting
(i.e.  ATT will likely be the correct setting on the noisy low bands and PRE
will likely be correct for 10m).  Remember that the K3 will remember these
settings for each band.  Once you have the correct setup on each band it
will automatically recall that PRE/ATT setting when you return to that band.
  
4.  Now adjust the RF GAIN knob counterclockwise until the antenna noise on
the meter just stops flickering on the meter.  This will be familiar to OTs
since this is the way we set RF GAIN many years ago on analog radios.

5.  Now adjust your AF GAIN knob for a comfortable listening level (mine is
normally 9-10 o'clock which may vary depending on what type of headphones
you have).

If you still don't like the amount of background noise compared to signal
levels, adjust CONFIG: AGC THR to a lower setting than the default 5.  This
which will reduce the apparent noise level by moving the AGC onset point
down and acting as sort of a noise squelch. 

Regarding settings for speakers, I never use them since I'm normally
listening for extremely weak signals on 160m or in contests and I don't want
ANY extraneous noise between my ears and the signals.  Perhaps someone who
uses speakers can add comments. 

I hope the above helps but please read K3NA's article for more comprehensive
suggestions (remembering that his setup is for AGC Off).

My general rule for all gain settings (PRE/OFF/ATT, RF Gain knob, AF Gain
knob, CONFIG: AF GAIN) is LESS IS BETTER (as long as you can hear signals). 
This is contrary to the thinking of some but following it will ensure that
you get the ultimate dynamic range performance available from the K3.

73,  Bill  W4ZV

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