GeosatPro CK1 - How to Shim

[starman345]

Got my new CK1 c/ku feedhorn this week and have noticed like a lot of these feedhorns, the scaler ring hole is larger than it needs to be making it difficult to get the feedhorn aligned with the dish. I've seen posts here of guys mentioning shimming things to make it work better, but what exactly can be done? I've thought about adding a couple more set screws but is there anything else that can be done?

 

[Lak7]

Duct Tape for me.

 

[Anole]

been there . . .

I made a little folded-metal bracket.
It acts as a shim, and a pressure-spreader, and won't fall out if you move the LNBf.

My original goal was simply to not put a dent in the side of the LNBf when tightening the holding-screw.
The part is outdoors right now, and the dimensions below are just a guess.
Adjust as necessary to achieve the goal.

I will try to zoom in on some old photos , but in the mean time I hope this explanation will suffice:
- Ya want a strip of aluminum (needs to be soft metal) maybe ½" wide and 1½" long
- Drill a hole in one end, just large enough so the LNBf locking screw will slide through
- fold the strip in half, around a small metal rod (small screwdriver shaft?) so the end with the hole aligns under the locking screw head
- the other end of the strip is now inside the big hole on the scalar where the LNBf goes
- due to the taper of the LNBf, it's necessary to insert the LNBf all the way toward the dish to make the gap large enough to install the bracket
- now, pull the LNBf away from the dish to its proper focal position, and tighten the locking screw.
- I also filed the end of the LNBf locking screw so it's flat. That spreads the pressure to the shim.

Yes, the end of the metal strip inside the scalar hole needs to be formed a bit to conform to the curve of the LNBf, but that's why you used a soft metal. -

edit: and here's how to set the skew on the CK-1, when you're aimed at your true-south bird.

 

[starman345]

Nice Ideas

Tim,
I've never tried duct tape on a feedhorn, I would think the set screw would just cut right through it until it hit something solid? Do you just wrap it around the feedhorn and push it into the scaler ring? Maybe I"m visualising something other than what you mean?

Anole,
I'm going to give your idea a try, I suspected if I asked here someone would have already done the head scratching and figured out something that works. I played with my setup yesterday for 20 minutes or so, it is a nightmare to try to keep all the angles, and distances just right when the feed is flopping around in the scaler ring and after tightening the set screw I noticed the feed is no longer centered in the ring. Despite all the setup problems the unit works pretty well, on both C and Ku. If I can get the feed and scaler ring solid and square to each other, I might be able to wring a few more db of signal out of it. Thanks for the ideas guys.

 

[truckracer]

I used pipe strapping used for hanging pipe. It comes in small rolls @ the hardware store. Just cut a piece and wrap the lnbf with it

 

[starman345]

I used pipe strapping used for hanging pipe. It comes in small rolls @ the hardware store. Just cut a piece and wrap the lnbf with it

I"ve got some of that pipe strapping here, have used it before for lnbf bracket mods. Pretty soft metal, that might be just what the doctor ordered. If it ever warms up I'll give that a try also, thanks

 

[14karat]

Anole, I've been working on a design for an adjustable scaler mount... now that's all trash and I'm sitting here looking at a bag of EMT conduit fittings wondering why I didn't think of this before...
Where were your pics 3 weeks ago???

 

[Anole]

what's old, is new again

Well, all I can really take credit for, is knowing a good idea when I see it. -

CadData came up with that bracket, several years ago right here on the forum.
I don't see his post just off hand.
But, here are some more recent pix by PopCornNmore, who did a beautiful job on 'em.
I believe other members have used that design, as well.

Fabbed 'em over at a friends house, based on memory.
We sat down with the scalar, clamps, and made a sketch on a pad of paper, actual size.
I then cut out the drawing with scissors, and test-fit it to the parts for final QC.
The brackets were made from that final mock up, and fit perfectly.

It my picture, the side support struts on the dish are ½ inch diameter,
Think that was the smallest conduit I could find.
So the conduit clamps are even larger (maybe ¾" ?).
Somewhat overkill for the dish they're on (1-click my avatar for the big picture).
Those LNB support struts are hand-made, too.

 

[14karat]

Whoa... I see now, those aren't EMT fittings, those are just standard box clamps... Ok, well, what I've got going will still work... this will help a ton.

 

[Anole]

Glad to hear you've come up with a new variation.
When you're ready, open a new thread, and post pictures.
I'll dig up similar designs by others (Linuxman came up with a similar solution), and we can post all the pix in the one thread.
I think it'd make a wonderful reference for those who follow . . . - :up