[aprssig] APRS Meteor Scatter test!
bruninga at usna.edu
Wed Nov 11 04:05:05 EST 2020
With the Leonids Meteor shower coming up in a week After Midnight next
Monday (Tues AM), maybe its time to have some fun with APRS again!
Last time we did this was 1998 and over 48 MS packets were seen over 500 to
600 miles on the APRS channel.. Here is the report:
THis year I propose not a free-for-all but just a few HIGH power stations
transmitting and everyone else in the country checks the next morning to
see what they copied.. Best TX stations are those with several
hundred watts and a beam. Even one such station would be a great test,
because on 144.39 we would have maybe 10,000 receivers. I dont have the
power nor the beam
So first, do we have any such stations? And then We can further organize
But it would go something like this. Say 4 TX stations around the country
would TX a continuous keydown string of short packets for 15 seconds. Then
the next, and so on till the minute is up and then start again. Xmission
is on 144.39 national channel to maximize the number of people that might
copy one. Transmissions begin at midnight and runs to 6 AM. We all wake
up the next morning to see what we got. Yes, this will burn the local
channel within about 20 miles of the TX station. but since the packets have
no path, they can only be heard in simplex range of a transmitter and
everyone is sleeping anyway.
But if a meteor happens, someone will likely capture it. Remember, our own
APRS stations these days only hears a packet say once ever 3 or 4 seconds
and that gives everyone a receive window of 75% of the total slots
available. And even if the 4 TX stations are not even synchronized it
doesnt matter because a given meteor path only exists for a fraction of a
second and only between two fixed 100 mile or so areas for that instant.
The original APRSdos had Meteor Mode built in and did the timing and
transmissions. WIth a very short packet and short TXD a single key down
could transmit about 30 packets during each 15 second period.
Oh, here is the original page: http://aprs.org/meteors.html
Look about 75% down the page for the map of that 2m experiment.
IGNORE the majority of that page. It was showing how an emergency response
station for example could go to an area of total devastation with all APRS
wiped out, and with enough power and persistence could likely get out an
emergency email message.
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