Norm,

I would love to see your design. I admit that the internet has made it much easier to locate and purchase small quantities of mechanical parts from industrial suppliers who are not accustomed to selling to amateurs, but lots of stuff can now be ordered from online websites in small quantity.

We are having a workshop on small antenna systems at NASA Goddard in Maryland on March 23 for any AMSAT people who can come, it would be great if we could show off your design there.

For shaft encoders, take a look at part 785-APS00B in the Mouser catalog, a magnetic absolute rotation encoder offering 0.05 degree resolution as claimed by their data sheet.

Dan

------ Original Message ------ Received: Sun, 24 Feb 2013 11:33:33 PM EST From: Lizeth Norman normanlizeth@gmail.com To: Samudra Haque samudra.haque@gmail.comCc: Daniel Schultz n8fgv@usa.net, Amsat-bb amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: inquiry about homebrew az-el systems

Gentlemen, Google is your friend here. I can kit a G-5500 class rotator from available shafts, bearings, gears, motors and such for less than $300. That's not accounting for economies of scale. Add some stuff from radio shack and the appropriate length of wire and you have for less than $500 a complete Az-El rotator and associated driving stuff, less antennas (which can be made reliably and cheeply) and antenna support.

A quick search on CL will yield a tower section reasonably. I got a bunch at $70 just a few months ago.

Step over from Skycraft to AES and see what they charge for this stuff.

The rotators sold now cannot be repaired, period. When the bit of kit on the top of my tower goes, I'll probably build one. Much cheaper that paying the 1500 that the top line mfgr wants for theirs..

I submit that the aformentioned project could be homebrewed by someone with a torch and access to a junkyard and tools no more complex than a grinder. The interface electronics are a little more difficult to build, but certainly wouldn't take a lathe.

Norm n3ykf