Noisy K-3 Receiver

[Jim HaRRIS]

Dick,

I've had the same experience as you describe.  You will get some explanations here on the reflector that sort of make sense so I will not try to repeat them.  What it comes down to for me is there is less usable S meter range and amplified background noise to contend with.  A great receiver but having to listen to that background noise is disquieting.  I think the noise/S meter relationship needs a solid review from engineering aimed at putting a bit of a knee at the bottom of the scale and in the process dropping the apparent noise level.  A supersensitive receiver is great but when all it's doing is digging out noise it's of little value.  I agree NR and related controls help a bit on the noise but it doesn't address the underlying situation.

Many of us over-the-hill folks have a sensitivity to noise that younger people don't have so it may be hard for them to understand and appreciate our concern.

Have a good day and 73.

Jim, W0EM


Date: Tue, 15 Dec 2009 23:44:26 EST
From: [hidden email]
Subject: [Elecraft] Noisy K-3 Receiver
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="US-ASCII"
 
Hi Guys,
 
I'd appreciate your thoughts as to why my K-3 receiver is so noisy.  I'd
really like to make this radio perform.  The radio is Serial #603F (factory
model) running 1.2.10.27.  I purchased the unit from the original owner a
couple of months ago so I don't know if it's always been this noisy but I do
know it was the same before I  recently updated software to 1.2.10.27.   The
radio is in immaculate condition and was never used mobile or bounced around.  
(it's a beautiful radio that looks like new!)
 
I say the receiver is noisy based upon listening to dozens of different
signals on: 40/20/15 m. and by doing numerous A/B comparison tests.  The
comparison tests were done with the K-3 Pre-Amp turned Off.  (and tried with ATT
on and off but mostly on to reduce noise).  
 
Radio 1: Yaesu FT-1000-MP w/AF Mod.  A signal is peaking S-8 and with the
no signal noise level is averaging S-1.  Therefore, the signal is peaking
aprx. 7 s-units above the noise based upon the MP s-meter and the signal sounds
loud and is way above the noise level.  Now I switch to the K-3:
 
Radio 2: K-3 tuned to the same signal with PreAmp Off and is peaking S-7
but the no signal noise level is noisy S-4 to S-5.  Therefore, the signal is
peaking only about 2 or 3 s-units above the noise level based upon the K-3
s-meter.  The result is that the MP has aprx. a 4 s-unit  S/N ratio advantage.
 
 
Thoughts: I realize that all s-meters read differently and the fact that
the MP s-meter shows a 4 s-unit stronger signal above the noise level  doesn't
mean alot.  But the fact is that the signal on the MP sounds MUCH louder
with alot more headroom above the noise level.  The K-3 receiver sounds so
noisy even with the S-7 signal that it isn't enjoyable listening to and that's
why I ran the comparisons because I couldn't stand all the noise.  Switching
on the K-3's NR, ATT, and/or adjusting the RF Gain does help some but the
signal still sounds noisy compared to the MP.  
 
Based upon "Reviews" of the K-3 I believe that I must have an unusual "K-3
noisy receiver" problem.
 
I'd sure appreciate your ideas on how I can get a better S/N ratio on my
K-3.      
 
Thanks!
 
73,
Dick- K9OM
 
     
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[K2QI]

Ditto here as well, and that's comparing my K3 #2730 to a stock FT-1000.

Wow, I thought it was just me.  I never gave it much of a second thought,
and just attributed the difference in noise floor/signal peaks to a more
sensitive receiver.

I've worked long pileups from 4U1UN and the FT-1000, and I don't recall ever
having as much noise-related fatigue as I get when I use the K3.  Please
don't get me wrong; I'm not bashing the K3.  It just seems the K3's noise
characteristics seem stronger and perhaps a tad harsher than what comes out
of the Yaesu.  I hope that makes sense...

73 de James K2QI

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Jim Harris
Sent: Wednesday, December 16, 2009 10:33 PM
To: Elecraft Email
Subject: [Elecraft] Noisy K-3 Receiver


Dick,

I've had the same experience as you describe.  You will get some
explanations here on the reflector that sort of make sense so I will not try
to repeat them.  What it comes down to for me is there is less usable S
meter range and amplified background noise to contend with.  A great
receiver but having to listen to that background noise is disquieting.  I
think the noise/S meter relationship needs a solid review from engineering
aimed at putting a bit of a knee at the bottom of the scale and in the
process dropping the apparent noise level.  A supersensitive receiver is
great but when all it's doing is digging out noise it's of little value.  I
agree NR and related controls help a bit on the noise but it doesn't address
the underlying situation.

Many of us over-the-hill folks have a sensitivity to noise that younger
people don't have so it may be hard for them to understand and appreciate
our concern.

Have a good day and 73.

Jim, W0EM


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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