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Re: AO-40 user population



On Sun, 2 Dec 2001, Adam L. Mendelson wrote:

> In summary getting started on sat's is a daunting task to the newcomer.

But I think that is because many folks see satellites as something that
takes a 50'tower, $1000 worth of AZ/EL rotators and controllers, and much
more in LNA's and coax.  (all true if you want to work in the basement).

But you can work almost all of the satellites with nothing but a small
handheld beam and a rig sitting at your picnic table.  Nothing could be
easier and less costly to get your feet wet.

Yes, to work satellites 100% horizon-to-horizon, you need all that stuff.
But you dont need ANY of it, if you just want to work them say 40% of the
time.  The added cost-to-availability curve is very steep.  But it starts
at almost zero to work them outside.  (I'm talking about "added" cost to
work satellites comapred to a nominal ham station).  Conversly, it IS a
very big investiment to go for the 100% unless you live on a mountain top
with no trees.  So set your goals to something easy to start with.

I for one, am perfectly happy operating satellites only 40% of the time,
but using nothing more than what I already have at ground level.  If I
really want to work a satellite during specific time when I cant find open
sky on my property, I just jump in the car and drive to the mall parking
lot and operate from  there.  I can even steer the car to move the beam
and still stay nice and warm inside the car...

Remember, for none of the LEO birds do you need an elevation rotator.
90% of all LEO access times are below 40 degrees.  And when the bird is
rarely above 40 (maybe a few  minutes per day), it is 10dB closer to you
and the signal is strong.  Thus, a small fixed beam angled up at about 10
to 15 degrees will work all birds 98% of the time.

Here is the table on my http://www.ew.usna.edu/~bruninga/rotator.html

EL  PCT CUM-% RANGE RNG-GAIN ANT-GAIN OVERALL-GAIN
--- --- ----- ----- -------- -------- ------------
10   32   32  3030     0       10         10
20   35   67  2440     2       10         12
30   17   84  1827     5        8         13
40    8   92  1460     6        6         12
50    4   96  1190     8        2         10
60    2   98  1020    10        0         10

And for the AZ rotator, simply use a $60 radio shack TV rotator and if you
want to automate it, wire it to two parallel bits on your LPT1 port and
run APRStk satellite tracking software, etc..

bob





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