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Re: Monitoring Meteors via Radio beacons?



> Subject: [amsat-bb] Monitoring Meteors via Radio beacons?
> Date: 1998-Dec-09 [Wed] 17:55:16 -0500

> I'm trying to find a way to record meteor scatter signals by
> utilizing AF9Y's weak signal FFT program.

> Obviously a known signal source would need to be monitored within
> the band of interest.
> I was thinking of monitoring a known beacon that would normaly be
> just above the noise at my location, and observing any "pings" or
> bursts of signal that would be typical of a signal reflected by an
> ionized meteor trial.  My problem is that I'm not sure of how
> critical the location of the signal source is for reliable meteor
> scatter monitoring.
> I would tend to believe that monitoring the calling frequency of 2
> metres for instance, would provide a better way of monitoring
> meteor scattered signals simply because of the number of stations
> in different locations that might be on the air
> as opposed to a single beacon.  On the other hand, the beacon is
> a CONSTANT source of signal. I guess the ideal way would be to
> utilize the scan mode in the receiver hi.

In Europe a lot of people monitor the VHF Band I (48 to 70 MHz) video 
carrier signals of television stations a few hundred or more miles away. 
This provides a 24-hour signal. It also is devoid of modulation (at 
least as perceived on SSB receivers). Doppler shift on meteor trails can 
also be heard, recorded and analysed.

This is far better than monitoring FM radio stations, with their speech 
and music modulation, or by monitoring a Ham calling frequency, where no 
pings may be heard simply beacause there is no one transmitting rather 
than a lack of meteor trails actually available to bounce signals off.

Using one source will give a reliable indication of propagation over one 
path, which will change in several ways:

1- a daily cycle which peaks at 6am local time, and dips at 6pm local 
time, due to random meteors.
2- during showers, a daily cycle that changes with:
  A- the position of the radiant in the sky, with the resulting path 
geometry altering.
  B- the availability of the shower radiant actually being above the 
horizon
3- during showers a build up of activity, to a peak, followed by a 
trailing off. Some showers have a broad plateau of activity. Some have  
just a short burst of activity, others have a short burst of higher 
activity superimposed on a broad plateau of above average activity.

In my opinion it is better to stick with one signal source, or monitor 
several in parallel, rather than changing around. A constant carrier 
signal is also much preferred.

There is a project in Europe that I can pass details on, later (details 
not here). It produces a monthly 'Radio Monitoring Observers Bulletin'. 
Christian Steyart (spelling??) is the compiler. More details later.....

Cheers,

Bob.



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