[RFI] Does a power pole generating RFI always generate ultrasonics?

[Don Moman VE6JY]

Quite a few sources do not generate enough ultrasonic energy to be heard on
the ground.   But an ultrasonic sniffer on a hotstick (ONLY operated by a
qualified lineman) positioned within a few inches of the offending hardware
certainly hears them well.  The only case I have experience with where the
ultrasonic sniffer did NO good was an internal micro arc inside the
transformer can.

On another RFI note... I received notice than a planned 500 kv DC
transmission line may be constructed within 1 km of my station.  Does any
one have any first hand experience with noise from a DC line? Corona?  I
know the AC-DC conversion equipment at the start of the line will be about
20 km away - also concerned about that noise carrying down the line and also
direct radiation.

73 Don
VE6JY





On Mon, Jun 7, 2010 at 11:46 PM, Stu Phillips <stu at ridgelift.com> wrote:

>
>
> I'm tracking a power pole near my QTH that is generating RFI from 15m on
> up.  With a combination of HF and VHF antenna, I'm pretty sure I've
> tracked to the correct pole.  This pole is generating more of a
> "cracking/poping" form of RFI rather than a constant arc like RFI.
>
>
>
> I recently built an Ultrasonic detector as an additional tool in my bag
> - it seems to work as I can hear tire noise, rubbing fingers, rat
> repeller etc...  BUT...
>
>
>
> When I check out this pole, I can't hear anything ultrasonic wise.
>
>
>
> So my question...
>
>
>
> Does a power pole generating RFI ALWAYS generate ultrasonics that are
> strong enough to be heard from the ground?
>
>
>
> Thanks!
>
> Stu K6TU
>
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