Got the BUD up, need help checking feedhorn mounting

[delta_charlie]

Hi all, I was able to re-assemble my 10 foot BUD last weekend and hope to try to mount the feedhorn this weekend. While putting it back together I noticed the feedhorn is mounted with three legs but the dish is an octangle and the legs mount to the dish between the eight sections so another words the legs are not spaced even. One leg gap spans two dish sections and the other two leg sections span three dish sections. I did mark the dish sections before I took the dish down but I did not mark the feedhorn leg positions. I'm thinking I will need to carefully check the feedhorn alignment and position.

Anybody run across plans for a simple homemade focal finder cup? Maybe I can rig up something made out of PVC pipe? Any tips or tricks that might help me make sure I get the feedhorn mounted correct would be most welcome.

It's not clear to me if the position of the feedhorn in relation to the north south axis is important or if the skew is set only by the position of the servo/probe.

Anybody have any pictures showing the back of the feedhorn and the front of the dish so I can see the relation of the feedhorn to the north/south axis?

For now I just want to try and lock on to one satellite and set the skew probe for either V or H and try to pull in a few channels. It would help a lot if I could preset the probe to V or H with the correct skew angle but I do not understand how the probe position relates to vertical or horizontal. For example - if the dish was on my due south satellite and I wanted V would the probe be straight up and down?

here is a picture of the feedhorn.

Here is a picture of the dish before it was moved.

Thanks, DC

 

[Lone Cloud]

It's a bit hard to see at the ange you show, but it looks like the holes in plate the legs bolt to aren't 1/3 apart.

I'd look there first and measure the mounting holes for distance apart. That might give you a clue which leg goes where.

I'll bet the legs are the same length.

 

[14karat]

I would think being octagonal it would have 4 legs...
A stick of thin-wall EMT conduit, bench vise, and a drill can remedy that situation...

 

[delta_charlie]

It's a bit hard to see at the ange you show, but it looks like the holes in plate the legs bolt to aren't 1/3 apart.

I'd look there first and measure the mounting holes for distance apart. That might give you a clue which leg goes where.

I'll bet the legs are the same length.

Hi Lone Cloud and the group, thanks for the reply.

You are correct on the holes in the plate not being 1/3 apart. The legs attach to an extension on three of the support trusses - there is a tab that extends from the back of the dish to the front between the 8 dish sections. The math does not work out with this design so the legs are not evenly spaced. I do have the tape marks on the leg that had the coax tapped to it so I know where it goes. What I'm not sure of is the position of the feedhorn in relation to the north/south access. When I marked the dish sections I simply started at the bottom and marked each going clockwise. When I went to put it back together I'm not sure I started at the same "bottom". I might be off by one hole in the hub as it looked different after moving the dish east and back west again - not sure I had the same west position that the dish was taken apart at.

I will install the feedhorn this weekend and then take a picture of it and post it here if it looks like it may be out.

Take care, DC

 

[Lak7]

I know the "Rule of Thumb" for the CoRotor was the Blue Servo Box points to 11 o'clock.
These may help.....
Feedhorn Assembly
Tune Up Of Your Satellite

 

[delta_charlie]

I know the "Rule of Thumb" for the CoRotor was the Blue Servo Box points to 11 o'clock.
These may help.....
Feedhorn Assembly
Tune Up Of Your Satellite

Hi Lak7, thanks for the reply. That's what I was trying to wrap my brain around. I also found a tiny graphic that helps show how the feedhorn gets mounted.

Now I should be able to confirm that I put the dish back together correct or have to move the feedhorn.

Looking forward to working on it this weekend.

Later, DC

 

[Lak7]

For centering, I use an Expandable Broom Handle vs. trying to measure with one foot on the ladder.