Friday, 31 July 2020

Perseid meteors begin, and a plea for help.

On a very late season's noctilucent cloud observing session overnight, it was noticeable that a number of very fast Perseid meteors are already coming in, almost two weeks before the shower's peak.

Over the summer, I've been thinking about and exchanging e-mails with various people about 'metallic bursts' of signals at 50MHz.  Superficially similar to meteor reflections, there are a few potential problems with this explanation.

Reflectors of radio, natural and man-made.
Firstly, some people definitely hear these bursts from European signals.  Whilst I hear occasional meteors pings from Europe, I never hear the quality of bursts that I hear when listening transatlantic. 

It may well be that this is a geometric effect, in that when I listen across the long distance of the Atlantic, I am 'looking' through a much larger volume of space, and thus have a greater chance of hearing meteor bursts.


But then, if this is the explanation, why do I not always hear such bursts when listening transatlantic?  Why do I not hear these bursts, if they are meteor-induced, at all times of the year?  Even without a discrete meteor shower, there are plenty of sporadic meteors to create paths if the 'longer path length' idea was correct.

I'm not trying to say that there is something spectacularly new to discover here.  But there are parts of the story that make no sense at the moment.  There are alternative explanations to meteor reflections as to why long distance signals might undergo the kind this kind of 'burst' propagation.

So, if you have any 50MHz capability over the coming three weeks or so, please do record any unusual periods of these 'metallic bursts'.  If you do, please record the audio using your digimodes software, and not something like HRD; this is to provide time synchronisation so that the signals can be decoded later. 


2 comments:

  1. John, I try to understand why we should try to record during the perseid event? You will always record metallic bursts these weeks, I observed it even this evening without any ES propagation. The other challenge is transatlantic signals, the season is almost over and those signals are getting rare. Although I experienced transatlantic propagation in August in the past. If so I'll try to record for you. 73, Bas

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    1. Well, whether or not you want to record is up to you, of course. What I would like to do is listen during Perseids, grab the inevitable bursts you mention, and then see whether I hear the supposedly meteoric bursts outside the summer season as well. I don't think I will hear any such thing outside of summer, aiming across the Atlantic. Given it's easy to do, I think we are better with recordings than without.

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