Noob in the deep end. Some help here? ;)

[jugghedd]

I'm starting to realize that people do things a certain way for a reason. maybe this arm in the middle is just getting in the way and causing interference. I'm going to take it out build a nice tripod set up and start testing again. I started to think the waveguide may even be diverting the signal away from the LNB. I'm afraid this hobby is making me even more OCD.

 

[SatelliteAV]

You will find little difference in the amount of reflected signal between a properly positioned feedhorn on either a buttonhook or side arms design.

A button hook design arm typically sits in the shadow of the feedhorn/scalar and does not attenuate the reflected signal. The buttonhook design is often not stable or correctly positioned in consumer systems. Users will often stabilize the buttonhook on a consumer dish with side support guy wires to center and stabilize.

This is unlikely with your commercial dish, though I would suggest that you measure from the reflector edge to the center of the feed in several points around the rim to verify that the feedhorn/am is not damaged and out of the center (sweet spot) of the parabola.

 

[jugghedd]

I would have thought the buttonhook style feed has its window right in the sweet spot. Ive checked every way possible to see if anything was bent. I cant even imagine being able to bend it short of it falling off a tower or running over it with a car. Its pretty rigid.

The other thing making me want to use a tripod setup is that I cant find a way to mount the 621 so its consistent when i move it. I had it clamped to the arm. Any mount I would use puts it far away from center.

The other thing Im sure is a problem is that the dish is still on the ground. Its just so hard to adjust one thing without putting something else off drastically. That may have been a stupid idea to expect results on the ground.

 

[FaT Air]

buttonhook style feed has its window right in the sweet spot

Should be, the theory for it, and an lnbf, are the same. One more thing you'll also have to 'get right' is the skew. Would be a lot easier if it were on an AZ-El mount. Even easier if on a polar mount.
AZ-El - easiest to build but limited, must be manually re-aimed, and the feed skewed, for another satellite.
Polar - more complex but adjusts everything, azimuth-elevation and skew, automatically while moved from satellite to satellite.
I, only for a couple of days, had a newly acquired 1.2m propped up by a folding ladder and a couple of sticks.
BTW: how heavy is that dish. Being 'commercial' I venture to say, it must be heavy. Whatever type mount you go, it will also have to be heavy.

 

[jugghedd]

I think I am going to use a polar mount. They have tons of diagrams on their website and in the catalog with measurements and instructions. And, its big but very basic in design. I may use a 4 inch pipe like the one my mailbox is mounted on. Plows wont even go near that thing. Oh yeah, the catalog says its 137 pounds without the bracket.

So far, I think Im using 3 pieces of 1/4 inch C Channel aluminium with 6 inch long solid square stock sliders for length adjustment to the tripod sections just in case Im off on my focal point or use a different LNB that requires a change. I hope this works.

 

[FaT Air]

Think 1/4 inch may be a little 'light'. May 'jiggle' too much to be dependable. 1/2 inch conduit would be my choice. Easy to flatten the ends for attachments.
Here I'm using it to steady a temporary Ku dish pole. Lag bolt thru hole into the base. Didn't move all winter. (Photo shows the very temporary deck screws)
For length adjustments. Telescoping sizes. Cut lengthwise slots on the larger telescoped piece. Stainless steel hose clamps to 'fix' the length.

 

[jugghedd]

I think you may be right on that. But, this may have to do for the testing part. I think I'll upgrade after to make sure the wind doesnt shake it. I know Ill have to commit to it at some point and mount it. But, Id like to get at least a glimmer of signal first. Here's a few pics. I plan on putting either double small c clamps or drilling the arms where it adjusts and I have black tape holding it in place for now.

 

[Anole]

Is this a formed metal dish?
I didn't notice any pictures of the back side.
If so, is the back smooth (stamped)?
Or does it have a circular pattern in the metal (spun aluminum)?
If it's molded Fiberglas & thermoplastic resin, it'll have ribs.

If you click my avatar, you'll see a picture of a C band LNBF on a 36" dish. (not recommended)
Those support arms are 1/2" conduit.
Think it's the smallest available.
Worked fine, mechanically.
So, if I were doing a BUD, I'd use 3/4 or 1", not the 1/2" stuff!

Also, note the brackets and conduit clamps.
They provide lots of adjustability for only a few dollars!
Strongly recommended.
Not my design.
Something a forum member came up with, several years ago, and popularized by others.

 

[jugghedd]

Its almost definitely spun aluminium. It looks like a huge wok with the lines around it barely visible. The edge is rolled like a lip and it has a huge bracket stabilizing it on the back. Its like a big ring with angle brackets rivitted all the way around. Some of the thickest aluminum Ive seen for something non weight bearing or structural. I didnt use eletrical conduit but just aluminum C channel. I agree 1/4 is crazy small. But, the stuff is pretty thick and staying stable for now.

Thanks for all the ideas. The conduit clamps look like a good way to do that. I'll see if I can get some pics of the back side tomorrow and post them. Then its off to do some welding.

 

[LocutusOfBorg]

Isn't the transition device from wave guide to coax electronic?

Nope. No active components inside.

 

[jugghedd]

I'm getting some weird results and looking for some more input. I read a few places that the dish itself determines wether it's prime focus or offset. So, I assumed the "sweet spot" in mine would be the same after changing from centered buttonhook waveguide to LNB/F.

I put the tripod setup on and mounted the BCS621. Didnt have much luck finding anything on the meter. I popped an old universal Ku LNBF and got some signals but it was with the thing WAY off pointed to the side. I triple checked the dish for warps and bends and still nada. crossed string touches everywhere.

So, my question is: Did I read wrong about the dish determining the setup type and the LNB/F has to receive an offset signal if its made to? Maybe the sweet spot is different because of the whole setup changing so much? Maybe my signal was so far off that I could only receive i by pointing way off o the side and up?

I really cant wait to mount this thing. Too many unknown variables with a temporary setup.

 

[Anole]

The focal point is at the center, where the old feedhorn 'n waveguide was.
You need to put your LNBF there, and then aim the dish properly.
Dont forget "skew", if you try for a satellite away from your true south (your longitude).