[Elecraft] K3 receiver desensing on CW during contest

[W0MU Mike Fatchett]

I saw the same thing with a huge fairly weak pileup on 20m's today.  This
really needs to get fixed asap.  It makes working a pileup almost
impossible. 


"A slip of the foot you may soon recover, but a slip of the tongue you may
never get over." Ben Franklin
-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dave Hachadorian
Sent: Sunday, February 22, 2009 6:26 PM
To: Elecraft reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest

The behavior you are describing is almost the same thing I complained about
a couple weeks ago. In my case I was trying to sort out several signals
calling me in a pileup, but it's the same basic situation. Fast agc, even
with the highest threshold and slp=0, compressed them all into an
indecipherable mush.

I'll tell you how I deal with it, but I'm not recommending this for
everybody:

agc off
config af lim = 30 (tech mode)
use preamp on 20m and higher
no preamp on 40
no preamp + attenuator on for 80/160
plug headphones into speaker jack, so you don't hit the AF Limiter
threshold. (There will be some hiss, but not too
bad.)
RF gain as low as possible
AF gain as low as possible to protect your ears.

WATCH OUT FOR YOUR EARS WITH THIS SETUP!!

I am hoping that the Elecraft folks will raise the AF limiter threshold or
allow disabling the limiter. If the limiter is activated, all signals are
horribly distorted. 
Limiter threshold is abrupt and hard.

This setup is probably not for everybody, but it works great for me.

Dave Hachadorian, K6LL
Yuma, AZ


----- Original Message -----
From: "K2MK" <k2mk at comcast.net>
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Sent: Monday, February 23, 2009 12:45 AM
Subject: [Elecraft] K3 receiver desensing on CW during contest


>I had a great time with my K3 during the ARRL DX contest. I do S&P and 
>I was  trolling around with my filter width at 50Hz. Absolutely  
>outstanding. The  auto spot is equally outstanding.
>
> At 50Hz width it was quite clear that many stations call off 
> frequency.
> Using RIT, I could see that it was typical for them to be 70Hz or more 
> away from the DX station but I could not hear them in my 50Hz 
> passband. The real problem was when one of them was S9 or greater. 
> They completely swamped weaker DX stations. Sound within the passband 
> just blanked out. No band noise and no DX station. And there was no 
> recovery between dits and dahs. It was actually easier to copy the DX 
> station when people were calling directly on top of him. You could at 
> least hear him between the dits.
>
> (Obviously if I was calling CQ instead of S&P I would have a wider 
> passband and I would have just worked the stronger off frequency 
> station).
>
> For my style of operating this was a disappointment. I tried AGC-F and 
> AGC-S but I forgot to try AGC off. I also varied the AGC THR and AGC 
> SLP. I tried NR off and on. (I was not using NB). I tried PRE and ATT 
> off and on. I tried riding the RF gain. I tried shifting the passband 
> but shift doesn't work well when the width is only 50Hz. Nothing 
> helped. I also tried opening up the passband. That didn't help either 
> but I don't remember the results.
>
> This was not a one time thing. It happened at least 20 different times 
> on different bands. I guess this is perfectly normal. I was just 
> wondering what operational trick is available to compensate.
>
> 73,
> Mike K2MK
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list:
> http://www.qsl.net/donate.html

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

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html