Maybe Allan Weiner made a mistake locating in that area of the North East. Seems more susceptible to the aurora. What do those mysterious lights do to an HF radio signal?
Any thoughts...I'm not getting into any Area 51 type thinking.........hi!
Fred
Hi Fred,
Northern Lights = Glow Discharge = low level plasma. Plasma is a non-linear medium and as such, is a great mixer.
This effect is why HARP was placed where it was, with the main function to initiate at least two very high power signals a given frequency apart and come up with a difference frequency low enough to get deep penetration
for submarine one way communications.
Consider the usual problems of setting up or maintaining a super length SLF transmitting antenna to broadcast to the Subs.
The lower that frequency, the more complicated.
Add to the issues that if one wanted to change this frequency, the entire system would have to be changed.
However, the idea was if one transmitted two signals, with information on them, to the natural "mixer" of these huge plasma sheet arrays, you would get a sum and a difference frequency.
In a conventional close to ground or buried antenna system, you have all these issues of capacitance, current shunting, etc.
But if you move the "Array" to a very high place away from Earth surface, many issues go away.
Such low frequencies have bandwidth issues based on the frequency itself, adding to this bandwidth limit is antenna to earth complications, too.
Using the higher sky with active glow discharge plasma as a mixer and enough area wide to simulate the wave lengths of such a long antenna as a virtual antenna, you get away from the Earth bound antenna problems.
So, if you transmit two very high power signals 10 Khz apart and inject it to the mixer, you get the sum and the difference. Of course here, you would want the difference frequency.
Now looking at a modulated carrier, you can see the possible complications when you pass it through a plasma discharge. Fortunately there is skin effect for the typical signal.
how the people at HARP got past this I don't know but I understand they had useful mixing effects. One of the engineers there for many years is also a ham, he wrote a book.
Doing work on a 2 feet wide, 6 feet tall glow discharge tube with ID of 22.5 inches / 72 inches tall and pumped down to about 70 Km altitude, even passing well filtered DC for study of Sprites (Glow discharges 5 storm heights above thunder storms) for an MIT researcher, you would not believe the RF noise that showed up on a spectrum analyzer set up near the discharge tube.
Well past 2 Gigs. Anyway, that mixing is ONE thing that can happen with RF signals Vs the aurora. I would imagine as the sheets of plasma flicker about as they do, this would cause some interesting phasing effects, too.
Mike
WA1MNQ
