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Re: (meteorobs) 2nd Perseids [RADIO] rprt (LONG)
At 01:56 PM 08/14/98 -0400, Kind Lew scrit:
>...The title of this list is 'meteorobs' not 'visualmeteors'. :)
>And when you think about it, what other forum IS there now to cross
reference
>radiometeor observations with those by other methods?
>
>Please continue to forward summaries like that. And by the way, is there
>anyone right now on the Ham scene with a corresponding-image interest in
>correlating YOUR data with visual, video, or other radio observations?
Seems >like with SO MANY active Ham "observers" (or maybe "users" is a
better term), >there's real potential here to answer some interesting
questions...
There are apparently many in Europe, Christian Steyaert (sp?) among the
more active posters, who record radio meteors in a professional manner
using FM broadcast and television signals; but there seem to be many fewer
here in North America. The major problem with the data from hams is that it
is very rarely recorded in a manner by which there is much possibility of
correlating any particular reflection with a visual meteor. But there
actually are more who *do* take relatively careful notes than one might
think; the trick is for those who wish to perform the correlating to
educate the hams on what to, and how to, record to yield useful data. I
think the data available would be somewhat different from what would be
obtained from the typical FM/TV reflection.
One thing that the hams can offer that may not be available from those who
record FM broadcast reflections are more earth locations, which *should*
make it possible, I would think, to come close to determining to what
shower a meteor may belong. Jim Richardson and one or two other
"professionals" sent me some guidelines and thoughts on this subject about
a year ago; if I remember correctly, the consensus appeared to be that it
would be very difficult, indeed, to say that any given reflection resulted
from a shower compared to having come from a sporadic.
Unfortunately, the period over which the data might be collected would vary
considerably, and rarely would exceed an hour in any case since the hams
only record those meteors heard during an attempt at making contact with
another ham some hundreds of kilometers away. Schedules (attempts at
establishing two-way contacts) are typically no longer than one hour in
length and often as short as 1/2 hour. If contact is actually made, then
data collection would stop immediately once the necessary information was
exchanged to consider the two-way contact to be "valid"!
For now, it would appear to me that what information comes from the hams
could only be considered as "unofficial" backup to data
scientifically-recorded and compared to other such data. Perhaps, however,
the time will come when more valuable contributions by the hams can be made.
What I can say with certainty today is that for perhaps the first time in
North American history, at least a small number of hams are consistently
involved in day-to-day radio meteor scatter work. While there have been
various individual hams in the past (back to the early days of radio meteor
work in the mid-1950's, for example) who conducted such daily schedules,
the number was probably never higher than half a dozen at any one time
other than during a major shower; and the primary impetus was to find out
what could be done with meteor reflections.
Today, there may be half a dozen schedules on any given day and perhaps
more. I won't go into the technical details of why this is so other than to
mention that it has to do with the establishment and continuing growth of
high-speed morse code meteor scatter techniques here in North America. (In
very large part, Shelby Ennis, W8WN, the author of my previous posting, has
been primarily responsible for this growth. I believe that he often posts
to another astronomy- or meteor-related list at the e-mail address of
Skyway, but I don't know anything about that one. From Shel's post, it's
clear that he does have some interest and contact with the IMO.)
European hams have been using these techniques for several decades; but the
interest among North American hams has only recently become apparent. The
very high speeds in use cause almost continual illumination of potential
meteor reflections rather than the possibility of a very short reflection
(called a "ping") being missed due to the relatively-low duty cycle of
voice or "slow" CW (morse code below 100 words per minute). The situation
is somewhat anomalous to that of a bistatic radar (that is, a radar that
has the transmitter antenna located in one place and a receiving antenna
hundreds of kilometers away).
Clear skies,
SteveH
Shrewsbury Mass
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