Login  Register

Re: K3 AGC Mush

Posted by Merv Schweigert on Dec 04, 2011; 11:11pm
URL: http://elecraft.85.s1.nabble.com/Fw-CQ-WW-DX-Contest-CW-2011-Unofficial-claimed-scores-tp7060148p7061270.html

Eric,  thinking on this a little more, when you are testing there with
the pile
up generator do you have real antenna noise also on the radio?
I just checked on 20 meters for example and my noise is flickering S-3
almost the same level as the signals would be in the pile up when this
problem occurs.   So signals are close to the noise level or just above.
Perhaps testing with a noise generator set to S3 and the pile up generator
set for signals of S3 to S4 it may show up?
Merv K9FD/KH6

> We actually have a 'pile-up' generator we designed that sends multiple
> cw signals. So far it has not reproduced the issue here.
>
> What is the signal spacing you are hearing this with? All -exactly- on
> the same freq? Or spread out?
>
> 73, Eric
>
> _..._
>
>
> On 12/4/2011 12:20 PM, Jan Erik Holm wrote:
>    
>> This is exactly what I have noticed too. Not even 10 signals
>> are needed either.
>> /SM2EKM
>> -------------------------------------------
>> On 2011-12-04 20:53, Merv Schweigert wrote:
>>      
>>>> Also, in the heat of the contest or DX pile up most reporters do not
>>>> recall how they had their AGC parameters set (threshold, slope, AGC
>>>> decay soft/hard, fast or slow, and fast/slow settings etc. If you can
>>>> let us know your complete set up for AGC parameters, if you are using
>>>> headphones or speakers,  the signal strengths, CW or SSB, RX b/w, what
>>>> different settings you tried etc., that will be extremely helpful.
>>>>
>>>>          
>>> AGC DCY  =  NOR
>>> AGG HLD  =  20
>>> AGC PLS  =  NOR
>>> AGC SLP  = 000
>>> AGC THR =  008
>>> AGC F      = 200
>>> AGC S     = 020
>>>
>>> Headphones and speaker, no difference
>>> signals S3-S4 range
>>> CW
>>> all bandwidths,  use mostly 400hz and narrower.
>>> Tried AGC DCY = SOFT  (have PF1 programmed to switch that in and out fast)
>>> ALL settings of SLP and THR
>>> Turning off the AGC  improves the "mush".
>>> Loud signals are no problem at all,  the K3 handles loud signals better than
>>> any radio..  its when multiple signals of about S-4 are on this occurs,
>>> more
>>> than two or three, a pile up of same strength signals.
>>> I can understand it may difficult to reproduce unless you have a way to
>>> have
>>> 10 signals of the same strength, close to the same freq, and keying,  just a
>>> carrier will not reproduce the effect,  has to be keyed signals you are
>>> trying
>>> to copy.  They turn into a single level buzz of sorts.
>>>
>>> One note - If signals are below S9+20 and turning AGC off does not help,
>>>        
>>>> its probably not a DSP AGC or H/W AGC issue.
>>>>
>>>> Also, make sure to use the AGC Limiter menu setting to hard limit audio
>>>> levels if you use AGC OFF.
>>>>
>>>>          
>>> Never use NR or NB  and have the AGC limiter set for no AGC times.
>>>
>>> In my rough gestimation it seems that signals in the S3-S4 range need to
>>> not trigger
>>> the AGC as they do,  if one could set the THR to higher level? perhaps
>>> it would stop the
>>> problem.
>>> Is it possible to increase the range of SLP and THR to move the point
>>> where S-3 or S-4
>>> signals trigger the AGC?
>>> Thanks much Eric.    73 Merv K9FD/KH6
>>>
>>>        
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> 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:[hidden email]

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