Re: [amsat-bb] WTB: AO-40 BBQ Dish

[Jon Ogden <na9d@xxxxxxxxxxxxx>]

On Monday, May 26, 2003, at 15:45 America/Chicago, Jim Walls wrote:

> Jeff,
> Take a look at the photos of my PrimeStar dish and hour it is mounted. 
> Start at:
> http://home.earthlink.net/~k6ccc/Photo/Pics/S-band1.html
> and click Next for several more.

Hey Jim!

What a great way you mounted it!  I was trying to come up with a way to 
do mine and since I have all the mounting hardware, I think I'll follow 
your lead!  A couple of questions if I may:

1.) How does have the dish to slightly one side of the rotor assembly 
"balance" things?  Did you pick a spot where it and the UHF antenna 
would balance out the 2m antenna?

2.) I noticed no counter-weights arms.  Did you not need these?

3.) Your helix is about 2.5 turns.  I've seen references to 5.  What's 
the best to use?

4.) Does mounting the ground place for the helix place the phase center 
of the helix at the focal point?  I've been trying to figure out where 
exactly to mount the helix (mind you, I've not spent a lot of time on 
this yet).

The pics were helpful to me.  As for the guy who wants to mount a BBQ 
dish - forget it.  You have to modify that dish anyhow.  Mount the P*.  
While I've used a BBQ and find it works OK, the P* is going to be a far 
better antenna.

I can't wait to get mine up.  I'm not on the birds right now due to 
swapping out AO-40 antennas and some rotor servicing.  I've got to 
figure out time for ham radio projects while using most of my spare 
time to remodel our bathroom!  :-)

73,

Jon
NA9D
----
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