Hello.
I guess, these signals have rather semi-natural origin.
Such phenomena could be produced e.g. by some kind of non-linear processes of interaction of meteor traces (or some other mobile objects?) with man-made radio signals. The frequency drift can be explained by Doppler effect. Are the results of observations correlating with meteor activity?
These are probably not going to be natural phenomena. As discussed on page 3 of this thread there is significantly less activity on any given Sunday. I plotted this over a period of 6 weeks, every day, and without fail the activity of these sweepers was a lot less on Sunday than any other day of the week. Typically the Sunday level of activity was 1/10, or less, of the activity any other day.
Even if they were natural they would not be meteor related. Looking at the following image if each of these sweepers were a meteor we would be talking rates approaching 1000 meteors an hour for hours on end. Such a meteor storm would be quite an event…and the events in this image can happen every day for weeks on end as long as propagation is supportive. As a reference, the Leonids Meteor Shower for this year is predicted to produce about 25 or less meteors per hour at its peak.
A larger, and more detailed, shot of the above is here:
http://www.pbase.com/token/image/158277017/original.jpgCould this be a reflection of some signal with Doppler? Unlikely. First of all we never really see a candidate RF source, and that seems a bit odd, but there are also other reasons.
Look at this image:
That image is either of one or two sweepers, I think it is just one with a step or change of direction in it (because every time seen they are locked in reference to each other), but lets treat it as two, this results in lower numbers. The frequency is roughly 28300 kHz, and the swept width of just the longer section is a bit over 250 kHz. To cause a just over 250 kHz Doppler at around 28300 kHz would require an item changing radial velocity relative to the RF source by about 95000 km/h in the 11 seconds of that curve. Sure, some meteors can travel in excess of that rate, but little else near or on Earth does, and I think I have already given a fair argument for it not being meteors.
In that image also note the rough texture of the sweep. Many of the sweepers have this and some are much more pronounced than in that image. This texture would have to equate to either changing Doppler for some reason or changing source RF. Doppler changing that rapidly would mean extremely fast and repeating changes in velocity, either at the signal source or the object causing the reflection. If we consider again a meteor as the source it would have to be accelerating and decelerating radially relative to the source of RF, as far as I know a meteor will not do anything remotely like that. And as I said before, once you have eliminated a meteor as having anything to do with this signal few other things could have velocity changes on the order required for this to be Doppler.
T!
