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

Using C band polar mounts w/ ao-40



>Wow.  Good ideas.  If I got this right, the 5 deg inclination of AO-40
>means that for the most of apogee, it is mostly always 5 degrees higher
>than the GEO arc (TV sats).  SO take your 10 foot dish and TV activator,
>use the EL TWEAKER to bump it up about 4 degrees, and  you should be
>able to track AO-40 for hours... with only the longitude control!

I believe the declination offset adjustment on the polar mount would
accomplish this,  as opposed to the polar axis adjustment.  The existing
actuator arm would handle the longitude adjustment (to a point, as most
mounts are not horizon to horizon).

The polar arm (the part of the mount that points to the pole star) usually
is adjusted via a turnbuckle.  If I'm thinking correctly here,  that should
stay fixed.  The declination offset is a small angle added to the 90 degree
angle formed between the polar moount and the pointing angle of the
dish, to compensate for latitude (on the equator there would be no offset,
i.e. dish is mounted 90 perpendicular to the polar arm,  here in Ky it is
something on the order of 7 degrees or so, to recieve clarke belt sats).
For those of you who are astronomically inclined,  it's identical to the 
declination of a telescope mount (albeit not as adjustable).

The adjustment for this is typically found at the bottom bearing of
the mount,  and is adjusted in or out via a double-nutted thru bolt.  

I think it would be feasible to decrease the declination offset a fixed
amount in order to catch ao-40 out at apogee.  Technically,  it should be
possible to automate the declination adjustment to peak up on the sat
anywhere in it's orbit, no?

This all intrigues me as I am currently building an az-el mount for a 10'
reflector,  and also have an 8' for tvro reception.  I may sideline my
az-el project for now in order to see how the polar mount thing might
work with ao-40.  Certainly seems do-able, at least around apogee.

As always,  open to corrections/comments,

Rich, KA8OKH


-------------
Rich Dailey, KA8OKH - Phyllis Dailey, KB4NPI
mailto:okh.npi@gte.net
http://home1.gte.net/web22jfw/
-------------
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home