K3 VFO Tuning Noise

[Dave Hachadorian-2]

Yesterday afternoon, I installed new KSYN3A Synthesizer Boards in
my two K3's.  This morning, tuning one of the rigs across a dead
6 Meter band, I can hear a weak increase in white noise whenever
I turn the VFO knob.  I didn't notice that yesterday morning.
Perhaps the new synthesizer board has reduced the Rx noise
threshold such that I can now hear that noise?  This particular
K3 is s/n 059, and I know there is a VFO Noise Reduction Mod
available, but that mod describes the noise as "ticks."  The
noise I'm hearing is a small increase in white noise, even with
the 6 meter beam connected.

The noise increase is obvious, but subtle, and I wouldn't
consider it a hindrance to operation, but it has raised my
curiosity as to why I am just now hearing it.

Ideas would be appreciated.  Thanks in advance.

Dave Hachadorian, K6LL
Yuma, AZ

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[Jim Brown-10]

On Sun,6/14/2015 9:52 AM, Dave Hachadorian wrote:
> The noise increase is obvious, but subtle, and I wouldn't consider it
> a hindrance to operation, but it has raised my curiosity as to why I
> am just now hearing it.

I'm not hearing that noise, but the birdies are driving me nuts on 6M.
There are many frequencies where a birdie will show up on the P3, so you
tune for it and realize it's a birdie, not a signal. But the whole
purpose of the P3 is to help find signals. I'm seeing birdies 6 dB above
the noise floor!

Wayne -- this has been an issue for a LOOONG time. Is there a fix on the
horizon?

73, Jim K9YC
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[George Winship, NC5G]

<quote author="Dave Hachadorian-2">
<  This morning, tuning one of the rigs across a dead
< 6 Meter band, I can hear a weak increase in white noise whenever
< I turn the VFO knob.  

Dave,

I don't have a K3, but check to see if the NB is turned on on that K3. I notice the same thing on my KX3 when The NB is turned on.

73, George NC5G

[N5GE]

I have no birdies on 6m K3 1055.



On Sun, 14 Jun 2015 14:50:42 -0700 (MST), you wrote:

>
><  This morning, tuning one of the rigs across a dead
>< 6 Meter band, I can hear a weak increase in white noise whenever
>< I turn the VFO knob.  
>
>Dave,
>
>I don't have a K3, but check to see if the NB is turned on on that K3. I
>notice the same thing on my KX3 when The NB is turned on.
>
>73, George NC5G

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[Johnny Siu]

I do not have tuning noise except a number of internal birdies in 10m band.  Moving the cables around the KSYN3A area will minimize the birdies.
My K3 is an earlier model.  I remember I did the tuning noise modification some years ago.
73
Johnny VR2XMC
      寄件人︰ Amateur Radio Operator N5GE <[hidden email]>
 收件人︰ "George Winship, NC5G" <[hidden email]>
副本(CC)︰ [hidden email]
 傳送日期︰ 2015年06月15日 (週一) 8:55 AM
 主題︰ Re: [Elecraft] K3 VFO Tuning Noise
   

I have no birdies on 6m K3 1055.





On Sun, 14 Jun 2015 14:50:42 -0700 (MST), you wrote:

>
><  This morning, tuning one of the rigs across a dead
>< 6 Meter band, I can hear a weak increase in white noise whenever
>< I turn the VFO knob. 
>
>Dave,
>
>I don't have a K3, but check to see if the NB is turned on on that K3. I
>notice the same thing on my KX3 when The NB is turned on.
>
>73, George NC5G

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[wa9fvp]

The noise your hearing is caused by the frequency synthesizer, PLL trying to acheave lock.  When you turn the tuning dial, the PLL circuit switches to the new frequency.  The transients caused buy the frequency change creates a small frequency jitter that increases the noise floor.

A lock/unlock signal from the PLL circuit can be used to mute the audio during the tuning steps but muting process can also create noise.  The K3's receiver noise floor is so low on 6 meters that the tuning transients are well pronounced.

Jack WA9FVP
Willco Electronics.

[Petr, OK1RP/M0SIS]

Dave,

I remember that encoder tunning noise as same as birdies has been discussed long time ago already.

First of all regarding the birdies (if it is Your case also) check if all screws inside the radio (modules which you had to remove for the new synths installation) as same as the covers etc. are tightened enough. It was not my case, but I remember that lot of folks reported that after checking that mni birdies disappeared. (grounding, shielding etc.)

Also You can try to set SIG RMV function in CONFIG menu. See page 59 of the manual...

Regarding the tunning noise (if I remember well but I am not sure) there was some additional item in the menu to reduce this encoder noise so You can check if it is ON and if it will help...

Sorry if it is not so helpful.

73 - Petr, OK1RP
K3 #778