Fortec 1.2M dish elevation mod

[brentb636]

The problem with the Fortec 1.2m dish, is it's too heavy to conveniently fine tune the dish elevation setting. So here's my first solution, a pusher arrangement, to be used only in the tuning stage, to take the weight off the poor old operator and allow some micro adjustment.
Note the adjustable tension bolt at the bracket pivot point. [edit] There is a nylon washer on each side to promote controlled slippage and prevent metal-metal contact. [/edit] The bracket actually pivots on some 1/2" "dimples" in the steel, but this tension bolt holds the bracket dimples firmly in the appropriate hole, and provides a braking effect to prevent gravity "runaway". Regards to Anole for all the pics and advice he provided me on other such solutions.

 

[Cadsulfide]

Brent;

Nice workmanship!
Eliminates the need for that third hand.

 

[Larobpra]

Looks good Brent! I have been looking at how to make some kind of threaded adjuster for my 90cm Fortec dish. After getting used to having one on the old ChannelMaster dish, I really want to come up with something similar. Makes fine tuning the elevation a breeze.

 

[brentb636]

Stogie suggested to me that the 5/16" steel plate might be overkill.
If you can get a stiff aluminum plate, it might be an improvement in the design. I might be doing the same thing on my Fortec 90, with aluminum , if I can get it.

 

[skysurfer]

thanks for the idea! I have mine on a pole (not a plate like you) but I think I can probably make a temp bracket to put on the pole to attach one end of the adjuster to while I make my elevation adjustments and lock down the elevation bolts on the FS120 factory mount before I remove my temp bracket and long adjuster bolt.

 

[Cadsulfide]

Stogie suggested to me that the 5/16" steel plate might be overkill.
If you can get a stiff aluminum plate, it might be an improvement in the design. I might be doing the same thing on my Fortec 90, with aluminum , if I can get it.

Nonsense, no worries about it ever bending:up

 

[Mr Tony]

very nice

 

[brentb636]

Nonsense, no worries about it ever bending:up

The steel plate is definitely sturdy ! I asked for 1/4" but they had a piece of 5/16" scrap handy to chop, so that's what I got.

 

[Anole]

some history

Lookin' good, dude!
Kudos for your own personal interpretation.
Now, let's hear how well it works! - :up


As to other comments, when JsatTV had a similar conversation with the assembled masses, around a year ago, his turned out a bit different.
Since his motor shaft stuck up, he had room above the mount to put his plate, and used a screw to pull back on the top of the dish.
Here, the motor shaft enters from the top, so Brent wisely put his screw below the mount, and made it a pusher.
DirtyShame and some others did a similar pusher idea in some of the Primestar vs 2100 threads.

The other difference was, I suggested the dish elevation pivot bolt that fits in the new hole drilled through the dimple in the mount, be threadless.
See the JsatTV discussions for pictures.
Of course, if you only adjust the thing about once, it probably doesn't matter much! - :up

 

[Sadoun]

Nice improvisation. You may want to paint the plate to prevent rusting.

 

[skysurfer]

With great weather the last few days, I got off my ___ and got my FS120 properly aimed (well, pretty much, center arc is awesome but AMC-21 is a little disappointing so I have to review how to align the HH120).

My implementation was to take about a 7 inch piece of "L" angle iron, hacksaw it apart at the junction on one end about 1.5 inches, and bend it to form something I can attach to the "H" bracket of the FS120. I then drilled a few holes to give myself plenty of places to attach one end of the adjustment bolt and I attached the other end of the adjustment bolt to a HH120 slot that is part of setting the HH120's elevation.

I drive my HH120 to the due-south 0 position, hook up the fine elevation adjustment device, loosen the factory mount bolts to allow for elevation adjustment, hook up my SF-3000S and set it up for my due south satellite peaking DVB-S signal, turn the fine elevation bolt until maximum db signal strength/low BER is achieved, then lock down the factory bolts and remove my temporary fine elevation adjustment device because it would prevent the HH120 from turning otherwise.

 

[brentb636]

Nice idea, nice workmanship. Wonder how many variations we'll see for the purpose.

 

[Keith Brannen]

Brent and skysurfer: Excellent work and design!

One of these days I might come up with something similar for temporary adjustment of my 80cm dishes. I have one dish in particular where it would come in very handy (it's the one dish I swear at the most whenever I have to do any adjustments, as it thinks it's "funny" to slip and slide that tiny bit to avoid being locked in where I want it)!

 

[brentb636]

We feel your pain, Keith. The bigger the dish, the bigger the pain, too.

 

[tvropro]

I've been thinking about doing something like that with my 84cm ADTH. I like the way the threaded rod elevation adjustment works on my 90cm Primestar. Nice job

 

[skysurfer]

here we go.. am I the first to design a version two of a given project on this board?

Version 1 (posted earlier in the thread) ended up okay. I'd put on my device, peak the dish, then removed it. When I removed it, I lost about 1/2 to 1 db s/n as the dish slumped minutely forward. My best guess is that not only was I adjusting elevation, I was also tensing up the slop in the HH120 motor tube, and when I released the device, the motor slop caused the dish to move a little bit, and thus the loss of a little bit of signal.

Version 2 involves the same adjustment bolt and new brackets. The bracket attaches to the motor tube and the FS 120cm h mount so there is no motor tube slop involved. If slop occurs, both the dish and the bracket move together as one, not separately.

Version 2 appears to be where my journey on this project ends because it's perfect. I built it Sunday, put it on my dish Monday and aimed my dish. I got to 13.0 db s/n, removed the adjusment bar and lower bracket so my motor could move without the bracket possibly interfering with motor travel, and the dish stayed right there at 13.0 db, so I finally figured out how to build a fine adjustment tool that works without losing some signal upon its removal.

I'm going to have to find a new U bolt or find a different way of clamping the lower bracket to the motor tube for future use of this tool - the U bolt I used was one of the two on my FS 90cm dish that I need to redeploy when I figure out where I want to put it and what fixed sat I want to get with it.

now to see if I can figure out a fine elevation adjustment since my hh120 isn't trackign the arc correctly ever since I put a 120cm dish in place of a 90cm dish on it. I think that one is just plain loosen the bolts ever so slightly in order to make controlled small movements about the motor pole or mounting pole, depending on what needs to be done to slowly dial the arc in.

pics:

 

[brentb636]

Nice job. Wouldn't surprise me, though, to see you posting some other time, about yet another improvement !

 

[skysurfer]

Nice job. Wouldn't surprise me, though, to see you posting some other time, about yet another improvement !

the only two things I can think of off the top of my head is a fine azimuth adjustment and a way to lighten the load on the LNB holder.

fine azimuth adjustment - my dish is off to the west by a little bit of zero position as I peaked for max sig strength using the revision 2 tool and then found when I drove the dish a click west with my stab inline diseqc motor control, the signal strength increased a little bit.

When you loosen the U-bolts to adjust the dish about the motor post, the dish seems to slightly move forward - it doesn't stay straight on the pole when you have to loosen the bolts just enough to be able to get any slight rotation. Maybe spring loaded u-bolts would help with that issue if I can find strong enough springs to keep the dish straight on the motor pole yet allow just enough ability to turn the dish about the pole until I get it right where I want it and then can permanently bolt it down to the pole good.

the other fine azimuch adjustment is to see if a temporary parallel pole can be mounted near the motor pole with an adjustment screw going between the two poles, but I think that's harder to do than if I can temporarily spring-load some ubolts.

the other thing is the invacom is heavy that it seems to pull down the lnb holder a little bit and deform the dish. I can grab and move up the invacom lnb and gain some signal strength. My first thought was guy wire from the top of the fs 120cm dish to the lnb holder and use a turnbuckle for fine adjustment, but I"m thinking in the long run I"m slightly going to deform the top of the dish and that might not be a good idea to do.

I don't see any obvious structure below the LNB holder to add an additional brace that would push the LNB holder up by the right amount it takes. If the dish were fixed, I could attach one end to the wall and the other end to the lnb holder, but this dish moves and isn't a fixed dish so that makes the thought process more difficult in how to do it without deforming the dish.

 

[brentb636]

"the other thing is the invacom is heavy that it seems to pull down the lnb holder a little bit and deform the dish. I can grab and move up the invacom lnb and gain some signal strength. My first thought was guy wire from the top of the fs 120cm dish to the lnb holder and use a turnbuckle for fine adjustment, but I"m thinking in the long run I"m slightly going to deform the top of the dish and that might not be a good idea to do."

There ARE lnbf support struts on the dish, aren't there ? If so, perhaps replacing them with a threaded rod setup, would give an adjustment point for the lnbf position, don't you think?

 

[skysurfer]

There ARE lnbf support struts on the dish, aren't there ? If so, perhaps replacing them with a threaded rod setup, would give an adjustment point for the lnbf position, don't you think?

yes, there are support struts, but my thought about adjustment arms is that i'd be squishing in the edges of the dish (the edges are just a single ply of metal with a hole in it for the bolt.

I thought of something just now, but not how I could implement it since I don't have a sheet metal shop or even a brake. If one could bend with a brake and weld/bolt a rim of square tubing around the inside of the single ply lip on the back side of the dish, that could keep the dish's parabolic shape while providing strong support to do threaded lnb holder support rods or use the existing support rods.

the weight might exceed the limit weight of the hh120, tho, with a square tube stiffener added.