Primestar 1.2 Dish On C-Band Mount

[GreatFTA]

Guys, get a load of this idea!!!
I got a coupla of those mounts and arms lying around...

 

[Anole]

absolutely:

Yes, absolutely! That'll work fine. - :up
Search back for a thread by TurboSat for a similar lashup.
The only trick is to tilt the dish forward (nose down) about 24 degrees.
However much it is rated for in offset.
Then, you're good to go!
Won't have any trouble over stressing a little SG2100, either!

 

[GreatFTA]

Anole, it looks to me if I mount the Primestar dish as shown (with the setting already on the mounts I have) I really shouldn't worry about the offset you're mentioning. The Primestar dish would have the same angle as the original C-Band dish and track the arc fine.

 

[Mr Tony]

but the Primestar dish is offset so it doesnt have the same "look" angles as a Prime Focus dish

 

[GreatFTA]

but the Primestar dish is offset so it doesnt have the same "look" angles as a Prime Focus dish

You kinda lost me there, Iceberg. Because of the shape of the 1.2 dish, I have to do what Anole is talking about? Is that what you mean?

 

[Anole]

Your pictures were really a pain to view.
So, I may have overlooked something.

Just remember - project a line toward the sky, through the center of that big ring .
That's where the mount is aiming the dish.

You know in an offset dish, it "looks" up about 24 degrees from a line perpendicular to the rim of the dish.
So, where is your dish aimed? We already know where the mount is aimed.
Are they same place in the sky?
If you accounted for the offset, that was what I didn't see in the pix - sorry.

Take a tour on the Geo-Orbit site for drawings and words of wisdom.
edit: and look up that thread by Turbosat. Should make it all clear.

 

[Mr Tony]

You kinda lost me there, Iceberg. Because of the shape of the 1.2 dish, I have to do what Anole is talking about? Is that what you mean?

Because the dish has an offset built in, regardless of how you mount it to the mast, you still have to take that offset into consideration. Or you'll be aiming 22-25 degrees too high and just give you headaches

 

[GreatFTA]

Ok I understand that now, Iceberg and Anole. Those pictures are the only ones I saw and they were posted back in December.

 

[GreatFTA]

I am finding that out on the Primestar 84e C-Band project I am doing. I believe the principle you are telling me applies here. I went from a 1 meter to the 84e (because it is so easy to mount the C-Band LNB to the arm of the 84e!). I get some channels on 99w and a few on Satmex 6. But catching hell on other satellites. I may not be on the arc.

 

[Mr Tony]

also on the smaller dish you may only get a few of the really high powered transponders

 

[Anole]

Show us what pix you're talking about.
edit: oh, the ones you posted above weren't yours? They came off the 'net? Oh, okay.

Here are some of mine (I stole 'em fair 'n square off the 'net).
They show someone's personal pix of a mount similar to yours.
(oops: last two are the mount alone - a different mount )
I think in the UK, such mods are common, and the dealers have kits.
See below:

 

[GreatFTA]

Anole, look at the last picture on what I uploaded. The plate mounted on the Primestar dish look like is bolted right on the two bars of the C-Band mount. That was why what I was thinking would work as far as just mounting the dish straight to the mount. When I took down the old C-Band dish, I never touch the settings of that mount, based on where I live.
Just slide the mount on another plumb pole, go to the south satellite (which is 99w where I live) and tune in that bird.

 

[Anole]

While newbie Dee Ann was struggling to find her first bird, she posted this picture.
It shows where an offset dish appears to be aimed and where it is actually looking.
Contemplate the picture and think about it for a bit...

Go read Turbosat's thread.!.

The plate on the back of your dish needs to be tilted forward (downward, toward the ground) by around 24 degrees, and then the existing settings on your mount will work like a charm! - :up
IN FACT, I would make that how I'd do the initial setup.
- don't change any settings on the mount
- put the mount onto a plumb pole.
- move the mount to the top of the arc
- put the dish onto the mount (tilted downward)
- tune ONLY the azimuth and the down tilt 'till you find your TS bird!
- if the mount was tuned for your area before, and your new pole is plumb, don't adjust elevation nor declination on the mount AT ALL ! -

 

[turbosat]

Ftaman, one step I might not have mentioned when I came up with my primestar on polar mount , it makes it much easier to do, if you can do it, to align your mount to the arc with a c-band dish, first. That way you know its tracking, and the adjustments you will make on the small dish will all be in the way it sits on the polarmount. I just put the whole dish, a 7.5 dish, on the pole, made sure it was tracking the arc with c-band sats, then took the dish off, leaving the mount on there. You shouldn't have to adjust declination much, if any, on the polar mount, after attaching the primestar to it. PM me if you get bogged down.

 

[GreatFTA]

Thanka TurboSat for your response!
At this point I won't be doing much as far as what we're talking about. I had back surgery back in late May and I am still under doctor's care until mid July. The mounts I have was taken down from working systems. I collected them from folks who never use C-Band. I have reinstalled C-Band dishes with very little trouble as far as reajusting the settings. I never tried to use Primestar dish on one of the mounts. In the meantime while I am off from work I am going to study your plans. Do you remember the thread your plans are posted?
Thanks!

 

[turbosat]

I remember it, worked on it sev days before I got it tracking correctly. I don't know if it would still be accessible on here or not, that was back in 2007, summer or fall. Worked pretty well, but I kept tearing up cheap actuators scanning for ballgames and such, and finally sprung for a DG380 motor a couple of months ago. Best investment I've made for fta yet! Dead-on accurate tracking, and a lot less angles to consider when setting it up, lol. But the polar mount project was fun, I still use it, just not as often. I can make some more pics for you if you need it, I have a little better camera now.

 

[GreatFTA]

I found the threads, turbo! I am studying it now. Interesting. I will keep yall posted as time go.

 

[primestar31]

While newbie Dee Ann was struggling to find her first bird, she posted this picture.
It shows where an offset dish appears to be aimed and where it is actually looking.
Contemplate the picture and think about it for a bit...

Go read Turbosat's thread.!.

The plate on the back of your dish needs to be tilted forward (downward, toward the ground) by around 24 degrees, and then the existing settings on your mount will work like a charm! - :up
IN FACT, I would make that how I'd do the initial setup.
- don't change any settings on the mount
- put the mount onto a plumb pole.
- move the mount to the top of the arc
- put the dish onto the mount (tilted downward)
- tune ONLY the azimuth and the down tilt 'till you find your TS bird!
- if the mount was tuned for your area before, and your new pole is plumb, don't adjust elevation nor declination on the mount AT ALL ! -

Just flip the offset dish UPSIDE-DOWN on the mount, with the LNB at the TOP. That'll bring it in line almost perfectly. Otherwise, trying to get 22 to 24 degrees declination with spacers, might cause a lot of stress to the mount.

Offset dish elevation angle set up and pointing.

 

[Anole]

Just flip the offset dish UPSIDE-DOWN on the mount, with the LNB at the TOP. That'll bring it in line almost perfectly.

If you spin the dish 180° (upside down), then you'd need to tilt it back (up) about 24 degrees from the flush position FTAman has shown in his picture.
The bottom line is: the dish looks either up or down 24 degrees, so you have to bolt it to the mount ring, accordingly.
It never looks perpendicular to its rim (when viewed from the side), as shown in the drawings mentioned above.

 

[GreatFTA]

Wow...
This is DEEP.