[MilCom] 254.2 Calgary Approach control Booming in now

[David I. Emery]

On Sat, Feb 03, 2007 at 03:58:53AM +0000, vampire11 at comcast.net wrote: 

> Calgary app control booming in now on 254.2 here in north Georgia. The
> best signal I have got yet. I have my log periodic pointed ESE now. 

	I've just run an orbit program based on what I THINK are the correct
TLEs for Skynet 4 and guess what ....

	Skynet 4 is about 0.7 degrees above the horizon at Calgary,
Alberta as I type this at 11:31 PM EST.   Not a lot, but the radio
horizon is lower than the optical one (radio waves bend more near the
horizon) and if the antenna for the UHF ATC site  is up on a tower with
a really good view of the horizon at 95.9 degrees (almost due east) it
is quite possible that it is currently making it into Skynet 4.

	And MUCH MORE INTERESTING ...  Skynet 4 is in an inclined orbit with
an inclination of 3.52 degrees and is very close to the top of its figure
8 daily track where it would be highest in the sky at Calgary.

	This CERTAINLY explains why this traffic is only audible around this
time every night as the satellite goes below the horizon at Calgary most
of the rest of the day and the signals getting into it would either be weak
or non-existent.

	So I think it's case closed, folks...

	Of course I'd be VERY curious as to what UHF frequency at Calgary is
getting into the transponder - guess it's AIRNAV time...  

-- 
   Dave Emery N1PRE,  die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."