[Elecraft] KX3 Filter Blow-By

[Igor Sokolov]

Olli,
Very interesting. I have experienced this effect recently when operating 
from 2400 m high summit as TA4/UA9CDC. I thought the reason is opposite side 
band not well suppressed. Therefore I was going to ask Wayne to send me that 
beta firmware they have developed in order to rectify the issue. Now I will 
have to try to see if that VFO NR is the culprit.
Here at home I have usually pretty high noise level that simply masks these 
weak artifact signals. Therefore it is not an issue. But I have purchased 
KX3 just to go to quiet locations and enjoy operating from there and being 
able to hear what I miss from the city.
Thank you for very interesting info.

73, Igor UA9CDC
----- Original Message ----- 
From: "Oliver Dröse" <droese at necg.de>
To: <Jimk8mr at aol.com>; <elecraft at mailman.qth.net>
Sent: Tuesday, October 09, 2012 12:59 AM
Subject: Re: [Elecraft] KX3 Filter Blow-By


> Hi Jim,
>
> did you have VFO NR enabled by chance? I suppose yes, as the KX3 is quite
> unusable on the high bands without. :-( There is a known issue = bad 
> effect
> of the DSP leading to "artifacts", i.e. hearing signals +/- 5-6 kHz again
> from strong stations. If you turn off VFO NR it goes away, but then the 
> VFO
> noise is much too strong. :-( Another bad effect is even with VFO NR 
> enabled
> if you tune "over" strong stations you suddenly have strong VFO noise 
> until
> you stop turning the wheel. Afterwards it's gone again. And if you turn 
> the
> VFO fast enough you will not even recognize even 59+ signals. :-( All
> problems from the VFO NR DSP implementation as confirmed by Elecraft. And 
> no
> matter if with or without roofing filter and with/without 8 kHz shift
> enabled. Still wonder why nobody else is complaining about those effects?
> Cannot be that everybody has an s4 noise level on 12, 10 & 6 m that would
> mask the VFO noise and thus no need to enable VFO NR.
>
> I documented all those effects on video and sent it over to Wayne. He said
> he and Lyle are working on it, hopefully with some results soon, otherwise
> the KX3 is of no use for a high band op like me. :-( Never seen such
> problems with *any* other rig owned so far ...
>
> 73, Olli - DH8BQA
>
>
>
> ----- Original Message ----- 
> From: <Jimk8mr at aol.com>
> To: <elecraft at mailman.qth.net>
> Sent: Monday, October 08, 2012 7:46 PM
> Subject: [Elecraft] KX3 Filter Blow-By
>
>
>>A recent KX3 owner (# 1677), I've noticed hearing out of passband  signals
>> from loud CW stations. I can hear such stations up to several KHz  away. 
>> I
>> suspect the range is limited by the audio response of the system,
>> including
>> my ears. Both sides of zero beat, though less so on the opposite side  of
>> the zero beat.
>>
>> In the CA QSO Party this weekend, maybe the loudest 10% of the stations 
>> on
>> 10 CW Saturday afternoon were leaking through. (I've heard the leakage on
>> other  bands as well.)
>>
>> I don't have any roofing filters. (I figured any stations weak enough 
>> for
>> me to need the filter to hear, would never be able to hear me anyway).
>>
>> Is this normal, or is there some shielding or other issue affecting my
>> unit? (It is a kit version).
>>
>>
>> 73  -  Jim  K8MR
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