Nice writeup, Don. Thanks!
But the one thing I haven't seen mentioned in this month's installment of
the noisy K3 discussion is setting the RF gain control. I got into the
habit long ago of using the RF gain to quiet the band noise to a reasonable
level -- after setting pre-amp, attenuator, and
Carl,
Backing off the RF Gain will preserve the dynamic range of the receiver,
and will move the AGC response further from the threshold (but it will
do nothing for the slope).
So, yes, that can be quite effective for reducing noise. Many do not
like to back off the RF Gain. I have heard
Note that my post referenced below sat in limbo for 4 days before showing up
on the list. It's a bit stale.
In the interim, one contributor gave some quantitative info about the noise
measured between CW elements when running full QSK with the RF gain control
set appropriately. If the noise
Problem solved.
When I built my K3 and came to the Owner's Manual setup procedures on
Page 51 - 'S-Meter and RF Gain control'. Not being in possession of an
XG2 I took the statement 'calibration is normally adequate using the
factory settings' at face value - and didn't calibrate the rf gain.
RF gain calibration has to be done, whether one has an XG2 or not.
Without the XG2 you can set it to factory defaults.
The RF gain calibration has to be done after the K3 is assembled and
can't be done to the board before shipping a kit version.
Although it works without the cal, there are
John Chappell G3XRJ wrote:
My K3 is srl 46xx and the only way I get the quiet background I desire
is to turn the AGC off.
SNIP
Problem solved.
When I built my K3 and came to the Owner's Manual setup procedures on
Page 51 - 'S-Meter and RF Gain control'. Not being in possession
On 10/12/2010 8:10 PM, Bill W4ZV wrote:
be sure to download the latest K3 Utility (at least
1.3.10.11 or later)
If it has been released I can't find it on the ftp site?
GB 73
K5OAI
Sam Morgan
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Elecraft mailing list
Home:
k5oai wrote:
On 10/12/2010 8:10 PM, Bill W4ZV wrote:
be sure to download the latest K3 Utility (at least
1.3.10.11 or later)
If it has been released I can't find it on the ftp site?
Still in beta but should be released soon. It works FB on two different
units here so I believe
Bill,
If you do get an XG2, be sure to download the latest K3 Utility (at
least 1.3.10.11 or later) which correctly saves the parameters. If
anyone else has done RF Cal recently (i.e. in September), you should
redo it with the new Utility when released.
Where does one get 1.3.10.11 or
Did 1.3.7.26 have this problem? I just used it for RF cal a few minutes ago.
Chuck, W5UXH
Bill W4ZV wrote:
If you do get an XG2, be sure to download the latest K3 Utility (at least
1.3.10.11 or later) which correctly saves the parameters. If anyone else
has done RF Cal recently (i.e.
W5UXH wrote:
Did 1.3.7.26 have this problem? I just used it for RF cal a few minutes
ago.
Probably OK. I used the oldest I could find which was 1.3.7.5 and it worked
OK.
--
View this message in context:
For me, it is more than a perception. To demonstrate this to myself, I used
the XG-2 set at 50 uV (so a good strong S9 signal) and for my normal
operating setup I see a tone (from the XG-2) in the presence of very
noticeable noise on an oscilloscope when looking at the K3 audio output.
I
I`ve been following this thread with interest as I have the same
perceived problem as John - and think all K3s exhibit this symptom.
I do not believe anyone has mentioned signal to noise ratio and surely
this is fundamental ?
I work a lot on 160m trying to dig out extremely weak signals using a
Don,
Thank you for your responses and for your efforts on your webpage.
However, I should have made it clear that I'm not in a noisy environment
and just to make it absolutely clear I've made another recording without
antenna connected to the K3.
Main and RX antenna physically removed, pre Amp
G3XRJ wrote:
Finally I must point out that I'm not saying the K3 is a noisy receiver
but rather, whatever the AGC does in its present incarnation in the
digital stream, has the effect of increasing the 'rf gain' from 12
o'clock to nearly 3 o'clock on overall system noise.
Rather than
John,
Your recording has substantiated the cautions that I have mentioned.
First, attempts to evaluate the K3 AGC response with no signals on the
band will lead you in the wrong direction.
Secondly, you apparently have the AF Gain well advanced, perhaps even at
maximum.
Third, you have
Don,
Thanks for response again.
Recording was made from 'line out' so af gain not in play.
Havn't had chance to try your suggestion yet but think I've already been
there.
73
John
John,
Your recording has substantiated the cautions that I have mentioned.
First, attempts to evaluate the K3
I like to listen to a receiver with the rf gain set to just below
antenna atmospheric noise and AGC on - and not raising the rf gain when
it is switched on.
My K3 is srl 46xx and the only way I get the quiet background I desire
is to turn the AGC off. This necessitates having the AF limiter
Interesting. Many of us have wanted just the opposite. The ability to
hold off AGC action until even high levels than the THR value allows
now. Perhaps in the future
73 de Brian/K3KO
On 10/8/2010 12:22, John Chappell G3XRJ wrote:
I like to listen to a receiver with the rf gain set to
reduction does
help, but it would be nice to quiet this down as John suggests.
My .02
Steve, W1ES
-Original Message-
From: John Chappell G3XRJ j...@g3xrj.com
Sent: Oct 8, 2010 8:22 AM
To: Elecraft@mailman.qth.net
Subject: [Elecraft] K3 AGC THR doesn't go low enough
I like to listen
Steve,
The solution is to RAISE the threshold. I run mine at 008 which is the
max. I also run the slope at 002 which makes the K3 AGC response more
like my K2 - weak signals sound weaker than stronger signals. You can
alter the slope without running into the situation where the K3 sounds
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Don Wilhelm
Sent: Friday, October 08, 2010 11:03 AM
To: Steve Wedge
Cc: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 AGC THR doesn't go low enough
Steve,
The solution
to quiet this down as John suggests.
My .02
Steve, W1ES
-Original Message-
From: John Chappell G3XRJj...@g3xrj.com
Sent: Oct 8, 2010 8:22 AM
To: Elecraft@mailman.qth.net
Subject: [Elecraft] K3 AGC THR doesn't go low enough
I like to listen to a receiver with the rf gain set
, 2010 9:25 AM
Subject: Re: [Elecraft] K3 AGC THR doesn't go low enough
John, I've noticed the same thing: the AGC does seem to make the
receiver - in the absence of signals - roar quite a bit with my early
(#770) K3.
I've attributed a lot of the noise to computer and suburban hash
Don,
What I should have mentioned in my initial post was that the recording
was made at midday on 80m and the noise from the antenna was only s1.
For a given setting of the rf gain, increasing the threshold to 8
increases the noise, as can be heard in the recording.
John G3XRJ
The solution
John,
I find that true too - but ONLY under the following conditions:
1 - the preamp is turned on
2 - the attenuator is off
3 - I set the K3 to hear only noise (no signal)
If I set the preamp off and attenuator on (normal operation with my 80
meter antenna) and then set the AF gain to listen
Re:
...the only way I get the quiet background I desire is to turn the AGC off..
and
I had resigned myself to living with the AGC off because I can't stand
the sound of the audio with it on in CW mode
(I've come close to selling it because of that many times),
AHA!!!
Whenever I've posted a
I had resigned myself to living with the AGC off because I can't stand
the sound of the audio with it on in CW mode..
I have similar perceptions in CW mode and generally leave AGC turned off.
The only problem I've encountered living in Florida is that on the 40m-20M
bands, the 100 kHz/sec sweep
I have thought about John's wish for more AGC control. The K3 has a lot of
gain, I wonder if greater attenuator control would be more useful. I would
like to rotate in another 10 or 20 dB attenuation at times when operating
lower bands. I would guess my that wishes would require hardware
I would concur with Don. I do not use the preamp unless the noise level is
very low. I use the attenuator on load bands or when there is a substantial
noise level. I use AGC as I don't want to damage my hearing accidentally.
Bill
K9YEQ
John,
I find that true too - but ONLY under the
I seem to have trouble convincing some to raise the threshold to
combat the noisy effect. Please read all below carefully, and I believe
I can offer some explanation.
Let's study what the AGC SLP and AGC THR settings do and try to relate
them to the perception that the K3 is noisy.
IF --
...@mailman.qth.net] On Behalf Of Don Wilhelm
Sent: Friday, October 08, 2010 1:56 PM
To: m...@paxsen.com
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 AGC THR doesn't go low enough
I seem to have trouble convincing some to raise the threshold to combat
the noisy effect. Please read all
Don,
That's a good explanation. Hopefully those folks will read it however
many times it takes for them to understand that lowering the threshold
is the opposite of what they want to do. I suspect that MANY of the
complaints about the K3 being a noisy rig are due to similar
John Chappell G3XRJ wrote:
Don,
What I should have mentioned in my initial post was that the recording
was made at midday on 80m and the noise from the antenna was only s1.
For a given setting of the rf gain, increasing the threshold to 8
increases the noise, as can be heard in the
In an effort to help those who perceive their K3 as noisy, and for
those who are not certain their AGC slope and threshold settings are not
right for their operation, I have added a page to my website.
Go to www.w3fpr.com and click on the link in the left column referring
to K3 noise and AGC
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