[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Satellite Rotators (fixed elevation)



I apologize...I think I squashed this inquiry by taking it off track:

Paul...KB3NDS asked:
>Since I can't move the assembly on the vertical axis, I have to get the
nominal elevation for most passes and lock it in there<

Hi Paul..

You will get many opinions from 10° to 30° fixed elevation depending on the
sharpness of you beam lobes. A very high percentage (I've seen 96% quoted)
of your passes will be below 50°. Also, as the satellites approach their
peak elevation relative to your location, they are closer to you so don't
need as much signal to hit them.  In these cases the edges of your beam
lobe(s) will usually suffice.

However, when your pass is just starting or has a lower max elevation, you
need more rf concentrated toward the horizon because the satellite is
further away. This sort of moves you away from splitting the 50° 50/50 and
just picking the 25° mark.

Bob Bruninga has put a lot of effort into simplifying satellite tracking and
suggests a fixed 10° with a 4 to 6 element beam for LEOs. I have seen higher
degree angles touted by others.

A last consideration might be ...whart is your real horizon?  If you have
mountains (hills) or thick stands of trees (buildings) that obstruct your
horizon up to 20° that should probably become your zero horizon and your
tilt should be up from there.

If you want to drive yourself crazy, Google : fixed elevation beam satellite

It's getting warmer here in the once frozen North...put it up and move it
around until you are happy!

Enjoy!

Roger
WA1KAT


>Paul D. Lenharr II (KB3NDS)
"Pain is temporary, Pride is forever!"
Charles County Tactical Response Team
NREMT-I, Firefighter, Haz-Mat Technician
Department of Homeland Security Instructor
(301) 399-9504<
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home