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Re: (meteorobs) Radio Observation of Meteors

John Elder wrote:

> 
> I'm not certain of what you're getting at here. Would the beacon send a
> time code (one of the IRIG codes, say, the one that uses a 10 kHz carrier).
> The receiving station could then calculate the dealy of the time code and
> determine the total path length.

Yes, some form of timing mark, or both transmitters and receivers
synchronized to a LORAN master station for example.

 Wind velocity could also be calculated
> from the doppler shift. If the receiving site did interferometry, or if two
> receiving sites were used for triangulation, the meteor altitude could be
> determined, as well as the lat/lon of the burn.
> 
> I think you'd lose a lot of data if you only ran 100 W, though. At 25 kW at
> 50 MHz we had plenty of signal to work with for most meteors, but about
> 10-20% were too far down in the noise to be useful for analysis (we were
> looking for atmospheric density and wind data, not doing meteor astronomy
> at the time).

	I was thinking of restraints of doing something like this within the
amateur radio bands, and within the budget of amateurs.  In my case I
couldn't afford the power bill for a 25 kW transmitter :-)  I'd like to
hear more about how you did the atmospheric density and wind data. 
Regrettably the information that I have on hand is limited to McKinley's
book, Meteor Science and Engineering.  Peak transmitter powers at that
time ranged from 1 kW to 100 kW, with the (I guess state of the art in
the late 1950's) Springhill site using 20 kW pulses (30 W average) on
32.7 MHz.

	Myself, to set up an experimental system I'd have to do it as a 
licenced beacon within the amateur bands. Therefore it would likely have
to operate on 430 MHz or above - to be able to pulse modulate or wide
band FM modulate the beacon for timing.  On these frequencies smaller
directional antennae would confine the transmitted signal in narrow
vertical beam (a compromise - we see less of the sky - but we gain more
effective radiated energy in this smaller beam).  Likewise on the
receivers, just a few kilometers away, higher gain antennae would be
used which would be directed at the sky above the transmitter.

	Operating on UHF of course is a compromise too, weaker reflections, but
higher gain antennae and fewer problems from ionispheric refraction
(which probably wouldn't be much of a problem with such a high angle of
radiation).

	I haven't done this yet myself.  I'm building antennae to attempt
moonbounce (430 MHz), but I don't have a 430 MHz beacon transmitter that
I can locate a few km from my location to see if I could detect meteor
echoes.

	As I'm out of the information loop I'm not current on what has been
done since McKinley's book (1961) was written.  I would appreciate more
current information or to be directed to where I could find out more on
either government funded projects or amateur work on direct detection
techniques.

				Ron (in Gander)

> Put some optical instruments in key positions and you could develop quite a
> data set!
> 
	That may have been one of the things that motivated me in this
direction, I spent over 9 years in a place where we rarely had a clear
view of the sky for any period of time.  I sure am enjoying it the view
now.  Another idea, if the radio detection method worked well, have it
set up to automatically trip a camera for exceptionally strong returns.

				TNX & 73,

					Ron (in Gander)
 

-- 
R & L Thompson, 9 Medcalf St., Gander, NF, Canada A1V 1R9
Tel (709) 256-1179, Fax (709) 256-8638, e-mail rlthompson@thezonedot net

Amateur Radio Station call VO1AV, FP5EK, VE1KM   Grid Square GN28qw
Location 48 57'08" N  054 36'43" W, 
Local time UTC - 2.5 hrs Summer, UTC - 3.5 hrs Winter

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