Topband: Help with new noise on topband

[Tree]

All - 

Maybe someone out there has dealt with this specific noise and 
can help me with possible sources.

This noise is local - about 0.5 to 0.75 miles away - towards JA.

The noise has about a 50 percent duty cycle - 7 seconds on and 7 
seconds off.  It has been on in the evening and morning - but has
been off during the day thus far.  It has a funny sound to it when
it comes on that sounds like it is producing some specific carriers
on the band - creating a sort of "swishing" sound when it comes 
on and goes off.

Seems to roll off such that I can't hear it on 40 meters, but it 
is still pretty strong on 80.  It was very easy to hear on my 
AM radio tuned to 1710 kHz when driving in that direction - about
0.5 miles away.

You can hear the noise here:

http://www.kkn.net/~tree/160/JANoise.mp3

Next step is to see if I can hear it with my 131 MHz DFing setup
(using a Radio Shack pocket scanner - and a 3 element homebrew beam).

I am guessing some kind of holiday decoration - or some device that 
is used in cold WX.  It almost reminds me of the electric blanket 
noise that was well documented a few years back - but with a much
longer period and on time.  

Any ideas appreciated. This thing is several s-units above my background
noise level towards JA and will be a real anchor to my Stew Perry score
if not resolved by then.

Tree N6TR
tree at kkn.net