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RE: New on AO-40



Hi Grant
I can give some comments to your letter:
Sunday/Monday passage was not so good for your location (which I have
input as 40,42 N and 88,89 W  ~ EN50nk,... right ?)

The main reason being the attitude during the pass, f. example at MA135
the squint was approx. 42,8 and at MA180 squint was 31,2.
Now nothing is sharply black and white here, but as a rule of thumb (for
AO-40's S1 x-mitter) best to have a squint lower than say 20.
AO-40 is using a 5 or 6 turn helix for S1,.. it's not so sharp, but
helix antena's usually have some nasty side-lobes (typically more and
more nasty, with increasing gain, hi)

The Wednesday pass certainly looks better for your location:
At MA110	03:55 UTC	squint = 51 degrees
At MA224	12:26 UTC	squint = 20    do.
At MA242	13:47 UTC	squint =  4    do.	Distance only
19.000 km !!!
(In UTC all of above is Thursday morning)

To summarize (simplified, sorry):
>From 4:00 UTC until approx 12:30 UTC you WILL get signals, but indeed
from around 12:25 the should really increase signal level, since squint
as well as distance is acting in your favour.

PS: For these things, just look at the line saying "PASSBAND", that's
when the transponder is working.
Just consider the VHF/Rx and UHF/Rx as channels for controlling the
craft.
For the time being !!! the beacon is ON from MA000 to MA255, but as you
have already found out, these are "subject to change without further
notice" hi.

Good luck, catch you on AO-40
Vy 73 de OZ4UI/Lars



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