Elecraft

P3 Phantom Signals

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Ken Widelitz-2

P3 Phantom Signals

I've noticed a large number of "phantom" signals on the P3. They look like
signals but when I turn the RX dial, they move along with the cursor. When I
turned the P3 off and then on, they went away of 40m but that same thing
didn't happen on 15m. Any ideas?

73, Ken, K6LA / VY2TT

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Eric Swartz - WA6HHQ

Re: P3 Phantom Signals

Administrator

Make sure your BNC cable between the K3's IF output and the P3 input is
securely plugged in. (I usually unplug and replug in the cable as part of this
test.) If you have an alternate BNC cable, try it too as its always possible
there is a poor connection between the cable shield and one of the connectors,
allowing external noise to leak in at the K3's IF frequency.

Also make sure this cable is not placed on top of switching power supplies or
near other possible noise sources.

73,
Eric
/elecraft.com/

On 11/27/2018 4:05 PM, Ken Widelitz wrote:

> I've noticed a large number of "phantom" signals on the P3. They look like
> signals but when I turn the RX dial, they move along with the cursor. When I
> turned the P3 off and then on, they went away of 40m but that same thing
> didn't happen on 15m. Any ideas?
>
>
>
> 73, Ken, K6LA / VY2TT
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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jh3sif

Re: P3 Phantom Signals

In reply to this post by Ken Widelitz-2

I have the same on my P3.
I guess the phantom signals come from synthesizer spurious. When K3 VFO tunes to the phantom signal by turning VFO nob, you will hear its carrier.
My K3 is not K3s but old one with original synthesizer. I am not sure on K3s or K3 with new synthesizer.

73 de JH3SIF, Keith

> 2018/11/28 9:05、Ken Widelitz <[hidden email]>のメール:
>
> I've noticed a large number of "phantom" signals on the P3. They look like
> signals but when I turn the RX dial, they move along with the cursor. When I
> turned the P3 off and then on, they went away of 40m but that same thing
> didn't happen on 15m. Any ideas?
>
>
>
> 73, Ken, K6LA / VY2TT
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Dave New, N8SBE

Re: P3 Phantom Signals

In reply to this post by Ken Widelitz-2

You do know that you can notch spurious signals out of your receiver?

There are instructions for doing so in the operating manual. It's kind
of interesting to see how it appears on the P3, though. The spurious
will tune across in reverse directions from normal signals, and usually
at double speed. If you've notched it out of your receiver (the
procedure jiggles the synthesizer frequencies a bit in the immediate
area of your receiver passband) you will see it approach your receiver
passband on the display and then magically disappear as it crosses your
passband cursor. It will then re-appear on the other side.

Pretty interesting effect, but perfectly logical, once you understand
what is being done 'under the covers' to prevent you hearing that birdie
in your receiver.

73,

-- Dave, N8SBE

-------- Original Message --------
Subject: Re: [Elecraft] P3 Phantom Signals
From: Keith Onishi <[hidden email]>
Date: Thu, November 29, 2018 11:43 pm
To: Elecraft <[hidden email]>

I have the same on my P3.
I guess the phantom signals come from synthesizer spurious. When K3 VFO
tunes to the phantom signal by turning VFO nob, you will hear its
carrier.
My K3 is not K3s but old one with original synthesizer. I am not sure on
K3s or K3 with new synthesizer.

73 de JH3SIF, Keith

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