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P3 Noise, no antenna...


Michael Foerster
 

Wondering if anyone can help me. 

I see some noise on my P3, within about 25 KHz above and 25 KHz below my K3s frequency.  If I move the K3 dial, the noise spikes above and below the frequency move with the dial. 
  The noise appears on all bands   I even disconnected the antenna from the K3 and the noise spikes persist on all bands.

Any idea what these noise spikes are from?  Is it just my P3?

I've searched the forum, but can't find any mention of the problem. 

Mike, W0IH


Patrick Novak
 

I had same experience and it was the power supply.

73
Patrick VK2PN

On 19/01/2019 09:19, Michael Foerster wrote:
Wondering if anyone can help me. 

I see some noise on my P3, within about 25 KHz above and 25 KHz below my K3s frequency.  If I move the K3 dial, the noise spikes above and below the frequency move with the dial. 
  The noise appears on all bands   I even disconnected the antenna from the K3 and the noise spikes persist on all bands.

Any idea what these noise spikes are from?  Is it just my P3?

I've searched the forum, but can't find any mention of the problem. 

Mike, W0IH


southdaleus
 

sometimes some leakage from the BNC connectors.   Try reseating them and watch the scope as you do it.  

Dale, k9vuj


On 18, Jan 2019, at 16:19, Michael Foerster <mfroster@...> wrote:

Wondering if anyone can help me. 

I see some noise on my P3, within about 25 KHz above and 25 KHz below my K3s frequency.  If I move the K3 dial, the noise spikes above and below the frequency move with the dial. 
  The noise appears on all bands   I even disconnected the antenna from the K3 and the noise spikes persist on all bands.

Any idea what these noise spikes are from?  Is it just my P3?

I've searched the forum, but can't find any mention of the problem. 

Mike, W0IH


Michael Foerster
 

I think you guys are right, I think it's the power supply.
   I put the rig on battery power and that cleans up most of the noise.

I'll try some ferrite cores on the PS leads. 

Thanks,

Mike


Michael Foerster
 

Yup, I wound the power lead between the K3 and the P3 with a generic (unknown mix) clamp on ferrite core and it cleared up the problem.
   If I disconnect the antenna, no more P3 noise. 

Thanks guys!

Mike, W0IH


Pete Oesterle <ve3hoh@...>
 

I had a similar problem with my K3.
it turns out the  SAMLEX 1235   power supply  had some noise on the DC.
Switch mode supply.
DC power leads   are maybe  1/2 in  from the  LPF  inside the K3.
Loose coupling of noise  on the  DC line.to the LPF 
K3  was the only  rig  I had this problem  with.
Shielding the  power leads or  placing a  metal panel  between the  wires and LPF  might help it.
My old  Atlas  210X   was  quiet.

😉


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Michael Foerster <mfroster@...>
Sent: Friday, January 18, 2019 6:42 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] P3 Noise, no antenna...
 
Yup, I wound the power lead between the K3 and the P3 with a generic (unknown mix) clamp on ferrite core and it cleared up the problem.
   If I disconnect the antenna, no more P3 noise. 

Thanks guys!

Mike, W0IH