noise

[Jacek Kubiak]

Hi folks,

 

I have noticed strange noise level in my K3 when  switch on my  Icom  756PROII with PC125. When Power supply PS 125 is  switched off again noise  disappear. Is it normal K3 behavior?

How about to use power switching type of supply to K3 in such situation??

Any comments on that??

Jacek Kubiak

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[Don Wilhelm-4]

Jacek,

I don't think it is a behavior of the K3, but that turning the PS 125 on
is creating a noise which is somehow being coupled into the K3.  It may
or may not be a problem with the PS 125.

The noise may be radiated from the PS 125 or it is being conducted into
the K3 on the power cord or some other cable plugged into the K3.  It is
also possible that there is a ground loop that is being formed by
something that is connected to the K3.  It could even be the power
supply that is connected to the K3 is creating the ground loop by
connecting the negative power supply output onto the mains safety ground
(Astron and some other power supplies do that and can cause such trouble).
To find out which, remove all cables from the K3 one at a time (except
the antenna and power) checking after each one to see if the noise is
still present - include any ground wires in this test. Finally, if the
noise is still present, connect the K3 to a shielded dummy load with a
short length of coax.  If the noise disappears, it is being radiated and
being picked up by the antenna connected to the K3.
If the noise still persists with only the dummy load attached, it is
most likely being coupled onto the K3 power cord.  Power the K3 from a
battery such as a gel cell or automotive type battery to test.  The K3
should now be completely isolated and the noise should not be present.  
If it is, you can look for the problem in the K3.  Be certain all the
fasteners in the K3 are securely tightened as a first step.

73,
Don W3FPR

Jacek Kubiak wrote:

>
> Hi folks,
>
>  
>
> I have noticed strange noise level in my K3 when  switch on my  Icom
>  756PROII with PC125. When Power supply PS 125 is  switched off again
> noise  disappear. Is it normal K3 behavior?
>
> How about to use power switching type of supply to K3 in such situation??
>
> Any comments on that??
>
> Jacek Kubiak
>
>

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[Ralph Parker]

>I have noticed strange noise level in my K3 when switch on my Icom 756PROII

My PRO III makes quite a noise on my AM broadcast receiver.
It seems to be coming from whatever p/s drives the display screen.

My neighbour's plasma TV makes terrible QRM on 160, 80, 40m as well.

VE7XF

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[Gary Smith]

> >I have noticed strange noise level in my K3 when switch on my Icom
> >756PROII
>
> My PRO III makes quite a noise on my AM broadcast receiver.
> It seems to be coming from whatever p/s drives the display screen.
>
> My neighbour's plasma TV makes terrible QRM on 160, 80, 40m as well.
>

My father's 756 Pro does the same to his AM radio. Seems that there's
a common thread here. Likely it's not your K3 at issue.

Gary
KA1J
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[Charly]

In my other station, my K3 sits above my FT-9000d.

Various operations, not limited to xmit RF, on the

9000 seem to make changes in the K3.

When the K3 is on, the 9000d shows increased

wide band RF out as indicated on the 9000d

built in screen, or maybe it is just the display.

Someday, I will do notated tests to be more

specific.  But, now-a-days, I just turn off the one

not in use.  73


Charles Harpole

[hidden email]

> From: [hidden email]
> To: [hidden email]
> Date: Wed, 15 Oct 2008 15:00:16 -0400
> Subject: Re: [Elecraft] Re: K3 noise from PRO II
> CC:
>
>
>
>>>I have noticed strange noise level in my K3 when switch on my Icom
>>>756PROII
>>
>> My PRO III makes quite a noise on my AM broadcast receiver.
>> It seems to be coming from whatever p/s drives the display screen.
>>
>> My neighbour's plasma TV makes terrible QRM on 160, 80, 40m as well.
>>
>
> My father's 756 Pro does the same to his AM radio. Seems that there's
> a common thread here. Likely it's not your K3 at issue.
>
> Gary
> KA1J
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> Elecraft mailing list
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> You must be a subscriber to post to the list.
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