http://elecraft.85.s1.nabble.com/Noisy-K-3-Receiver-tp4173832p4181405.html
> Hi James
>
> This has been my impression for the last 2 years when using our clubs K3's
>
> I decided to do a comparison with several radios.
>
> FT1000MP
> TS870S
> FT1000D
> TS850S
> TS930S
>
> If you blind folded yourself and did not look at the S-meter and switched
> between the radios, the K3 was always much more noisy. I did this test on 20
> meters and 40 meters. There is no doubt that the K3's correctly calibrated
> S-meter shows more activity. However when you dont look at the S-meter and
> just listen you can hear this apparent greater "noise activity"
>
> What is interesting if there is just signs of a starting thunder storm or
> light QRN, the K3 seems to make the QRN sound much worst. However when the
> QRN is very heavy its as bad as any other radio. I did also play with AGC
> setting and this result was always repeatable. I thought it was the AGC
> doing this, however I changed the slope and it appears to be the same.
>
> There seems to be a mid range window in the K3 that makes the radio sound
> much more lively. Above and below this windows thresholds it appears to be
> normal in every other respect.
>
> One thing thats very obvious with the K3 is that you need to play with the
> receiver EQ all the time. The difference can be very stunning when you get
> it right.
>
> There can be no one EQ setting that is good for weak and general purpose
> listening for both CW and SSB. The K3 on a flat EQ response is poor at very
> weak signal SSB work. However, when you adjust the EQ it seems to bring the
> radio back to life.
>
> The K3 needs a default setting thats similar to most analog radios, a
> defined bandpass filter that needs no EQ adjustment for CW and SSB. The K3
> for some reason needs a lot of highs and treble to sound decent. Even the
> CW note comes alive with real body like a analog radio when the EQ is set
> to high /treble boost. My belief is that most who say that the K3 sounds
> poor is for this reason. However when you boost the highs the receiver is
> very tiring on your ears. So you cant seem to win here
>
> There is something strange about how the DSP and the receiver chain works.
> It sounds great with strong normal signals on a quiet band. I do want to try
> a SCAF filter or some other audio filter to see if I can improve things. I
> dont have hearing problems and generally i try and leave the EQ set flat.
> However this has proved problematic for me, especially on weak SSB and CW.
>
> I am a casual K3 user and I dont own a K3, however I have spent enough time
> operating our clubs K3's which have a broad range of serial numbers many
> factory assembled. I would like to try and get the new DSP board to see if
> that changes much. Maybe it is because I am a casual K3 user that I notice
> all these quirks, these probably may disappear if i used a K3 every day. In
> the meantime I prefer any old analog contest radio at the moment.
>
> John
>
> --- On Wed, 12/16/09, James Sarte <
[hidden email]> wrote:
>
> > From: James Sarte <
[hidden email]>
> > Subject: Re: [Elecraft] Noisy K-3 Receiver
> > To:
[hidden email]
> > Date: Wednesday, December 16, 2009, 9:42 PM
> > Hi Mike,
> >
> > I've fiddled with all of the AGC, PRE, ATT, RF, and DSP
> > options on my K3,
> > and still experience a relatively high noise floor - at
> > least compared to an
> > FT-1000 side by side.
> >
> > I never gave it much thought until these subject came up on
> > the reflector.
> >
> > Cheers,
> > James K2QI
> >
> > -----Original Message-----
> > From:
[hidden email]
> > [mailto:
[hidden email]]
> > On Behalf Of Mike Harris
> > Sent: Wednesday, December 16, 2009 12:15 PM
> > To: Bill W4ZV;
[hidden email]
> > Subject: Re: [Elecraft] Noisy K-3 Receiver
> >
> > G'day,
> >
> > The simple fact is that the faithful will always suggest
> > that the K3
> > hears more, is more sensitive or is more transparent to
> > band noise
> > etc etc. Also you have to fiddle with the AGC, PRE,
> > ATT and RF gain
> > whereas other radios just sound nicer out of the box.
> > I don't have
> > a problem with fiddling with AGC and equaliser parameters
> > to tailor
> > the receive to my liking, but to have to do it to make it
> > sound
> > acceptable is another thing altogether.
> >
> > There is an often referred to AF filter module which
> > installs on the
> > main DSP board and apparently cuts out a lot of unnecessary
> > high
> > frequency audio. Sadly though often referred to it
> > just isn't being
> > made available despite very positive comment from some of
> > those who
> > have field tested it.
> >
> > The KAF2 filter for the K2 made all the difference in the
> > world to
> > listening to SSB.
> >
> > Regards,
> >
> > Mike VP8NO
> >
> > ______________________________________________________________
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