[Boatanchors] Peristent, annoying, intermittent, elusive QRN problem: help please!

[J. Forster]

Will White wrote:

> I have a local noise problem I am hoping someone can help me track down.  I hear
>
> S-6 or 7 loud, 'coarse' has on all HF bands, on all frequencies, though the
> intensity of noise diminishes somewhat on higher bands.  On 40M, my main band, it
> is all but intolerable, making QSOs with all but the loudest stations difficult,
> even at 12 WPM or so.
>
> The noise comes on for exactly 2' 15", and goes off for exactly 1' 25". Over and
> over. I have timed it many times over two weeks.  The noise is only there after
> dark. Aha! But I have searched and searched for an intermittent streetlight, to no
> avail. I have gone about three blocks in all directions from the house in this
> search, and also looked for automatic driveway/porch lights nearby, but can't find
> any. What the &*%$ can this be!??  I am really puzzled by the exact timing, since
> it would seem that a streetlight malfunctioning wouldn't do this, and a driveway
> light might stay ON for a specific time, but not off! HELP!
>
> --
> Will White, KD7BFX
> Seattle WA US
> King County, Grid CN87tq
> ITU Zone 6, CQ Zone 3
> ***************************************************
> "The wireless telegraph is not difficult to understand.
> The ordinary telegraph is like a very long cat.
> You pull the tail in New York, and it meows in Los Angeles.
> The wireless is the same, only without the cat."
>                                                       - Albert Einstein
> ***************************************************

I would suggest treating this like a fox hunt. Get a radio that covers the noise
band and that has an external jack. It doesn't have to be a super radio. Then make
yourself a shielded loop antenna. One design is to get a piece of coax with a
connector one one end to match the radio's external antenna jack and make a several
turn loop, maybe 4" x 10". strip the very end of the coax and cut back the jacket
and braid 1/2" or so.then strip the center conductor and solder that to the shield
of the coax where it enters the loop. You can tape the whole thing to a piece of
cardboard. The loop is directional. You can practrice on a broadcast station.  It
can also be used to look for conducted EMI by placing it next to wires.  The loop
should help you hunt the problem down.

Happy hunting,
John