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Re: APRS Meteor Scatter Event



On Fri, 6 Nov 1998, Roy Welch wrote:

> What beam headings during the shower?

A number of people have asked this.  The answer is to point at an area of
the country about 600 to 1200 miles away that will have the highest
probability of someone else also pointed your way.  If you look at my WEB
page which plots the locations of all the APRSdigipeaters in the country,
you can see where the major APRS activity is:

http://web.usna.navy.mil/~bruninga/digis.html   (You can ZOOM the map)

  All of the east coast From Florida to New England
  Chicago Illinois, Indiana, Michigan, MO, Iowa
  Tennessee, GA, Texas
  Washington State
  California (But southern Calif is already on 145.79, so you 
             (will have lots to listen for, but few will
             (be transmitting HIGH power with 100% duty cycle)
  But there are a few die-hard APRS ops out in the sticks that have good
  antennas too, and they may also be pointed at you...

Point your beam on the horizon.  That is the only way to get the max
distance and to also irradiate the largest volume of sky (meteors).

To minimize QRM to locals, the four regions of the country should transmit
for 15 seconds of every minute starting in the Norhteast at 00 and going
clockwise to the Northwest at 45.  The dividing lines are 38.00 deg LAT
and 95.00 deg LONG.  APRSdos will do this automatically for you.  It also
allows you to set a duty cycle if you want to share your 15 seconds of air
time with another local.

The literature says that the footprint on either end of any given meteor
trail path may be no larger than about 10 to 20 miles, this is why it is
OK for eveyone in your region to be transmitting at the same time.  Since
each persons energy will fall at different times at different locations.
If there are more than one of you in the same 10 mile footprint, then
choose different headings, and/or choose a duty cycle less than 100%.
(100% here means 100% of your given 15 second transmit cycle).  APRSdos
should show you the beam headings of other locals on the map.

For stations running manually, the way to include your BEAM heading and
ERP power in your packet is to add the three characters "^HP" on the end
of your packet.  

  Where:   H is your beam heading 0-9 and A-Z (representing 0-360)
           P is your power (0-9) where ERP=100*P^2
  
  Thus  a beam heading of 120 degrees is 12 (represented by "C")
  and an ERP of 2500 watts is "5"

So my complete packet would look like:

  WB4APR>FM19SX:]y[Bob^C4

Will plot me on the map in my grid square of FM19SX as a house with a
Yagi and a line pointed along a bearing of 120 degrees and whose length
is proportional to my power... (125 watts into a 13 dB ant = 2500 w)
The "Bob" here is useless for APRS and is ignored on receipt.

Here the ]y[ shows you as a house with a Yagi
       a ]-[ shows you as a house with a vertical
       a ]`[ shows as a Dish  (these are just afew of the 200 APRS ICONS)

The optimum times for Meteors in general are from midnight to noon with 8
AM being about the best.  But for a meteor shower, it depends on when the
bulk of the comet dust hits us.  If someone else cares to keep abreast of
the latest predcictions, please do so and keep us informed.  Im busy
enough trying to find two beams..  :-)

Oh, It also makes no sense to point your beam towards stations also in
your same quadrant as they will be transmitting when you are so they wont
hear you, and they are too close anyway...


de WB4APR, Bob


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