Phlat's Prodelin 1.8m offset on AJAK 180 H-H Mount

[phlatwound]

Wow, isn't it against the law in several southern states, to get bent over that far?
Amazing your AJAK goes all the way!

I haven't checked how mine are set yet but the AJAK manual states:

"Limit switches stop mount at 150 degrees rotation, adjustable to 180 degrees if desired."

The AJAKs are sweet devices. if there is something better out there I would like to see it.

 

[whatchel1]

Interesting project. You did it much differently than I would have. I wouldn't have used the long extender arms on on the dish instead would have tilled the Ajax down more and it wouldn't have minded. For me doing that would mean less chance of flex in the mount. I was going to do a project like this w/ 1.8 prod I had stored away. But in bringing it home the ropes that I had used to tie it down with broke and the dish went flying and busted it up. Why not make this a C/Ku using the sliding plate mount from Prodelin. Punch the right size hole thru that and mount a C/Ku feed there then put on a conical scalar. Just what I would do. Each to his own.

 

[phlatwound]

Interesting project. You did it much differently than I would have. I wouldn't have used the long extender arms on on the dish instead would have tilled the Ajax down more and it wouldn't have minded. For me doing that would mean less chance of flex in the mount. I was going to do a project like this w/ 1.8 prod I had stored away. But in bringing it home the ropes that I had used to tie it down with broke and the dish went flying and busted it up. Why not make this a C/Ku using the sliding plate mount from Prodelin. Punch the right size hole thru that and mount a C/Ku feed there then put on a conical scalar. Just what I would do. Each to his own.

Thanks whatchel1, this project has been fun, and I have learned a lot from it. Hate to hear about your mishap with that Prod 1.8. that really sucks, hope you run across another one.

The reason I used the long extensions to tilt the dish down is they are needed so the dish "looks down" far enough to track the arc.

It's a very simple formula to setup an offset dish on a polar or BUD H-H mount:

1.) Run mount to apex and aim to true south (93W for me)

2.) Set elevation bar to your "modified" latitude (37.7 degrees for me).

3.) Tilt dish down by declination + dish offset (5.3 + 22.3 = 27.6 degrees for me)

4.) Make a slight mount positioning/azimuth adjustment if necessary (I am slightly off of 93W long. so I had to).

5.) Celebrate a well-tracking dish with beverage of your choice.

As you can see, the only difference between the setup for an offset, as compared to a prime focus, is allowing for the degrees of offset of the dish. Period.

I had actually considered throwing a C/Ku LNBF/conical scalar combo on there for fun, and might still, but this dish's true mission for me is motorized Ku-only.

 

[stogie5150]

Interesting project. You did it much differently than I would have. I wouldn't have used the long extender arms on on the dish instead would have tilled the Ajax down more and it wouldn't have minded. For me doing that would mean less chance of flex in the mount. I was going to do a project like this w/ 1.8 prod I had stored away. But in bringing it home the ropes that I had used to tie it down with broke and the dish went flying and busted it up. Why not make this a C/Ku using the sliding plate mount from Prodelin. Punch the right size hole thru that and mount a C/Ku feed there then put on a conical scalar. Just what I would do. Each to his own.

Reason why he didnt do it that way is because it doesn't work. The mount MUST be set at your latitude to track properly. I just went through it with my Prodelin on a polar mount. i tried to use the mount to compensate for the dish offset, it would NOT track. Only way it would track is if I did it like phlat has his. I thought I could outsmart it too and save all the work, but it wouldn't work for anything.

Sorry to hear about your dish, I would have cried. :-(

 

[whatchel1]

See I was feeling it would be possible to add the el to the 22.5 offset then just set the declination for the 5.3 (in this case). Yep was pretty upset about loosing the 1.8 had had it in storage for years to play w/ later. What was really hard with the Prodelin dish was cutting it up and putting it in the dumpster. I knew thought that I could never put the chunk back in and fiberglass it back together in any way that would give a good enuff surface for a good parabolic curve.

 

[stogie5150]

See I was feeling it would be possible to add the el to the 22.5 offset then just set the declination for the 5.3 (in this case). Yep was pretty upset about loosing the 1.8 had had it in storage for years to play w/ later. What was really hard with the Prodelin dish was cutting it up and putting it in the dumpster. I knew thought that I could never put the chunk back in and fiberglass it back together in any way that would give a good enuff surface for a good parabolic curve.

I was too. In fact I would have bet MONEY on it. But I was wrong as teats on a bull. I did exactly what you describe first, The First Hillbilly (phlatwound) told me it wouldn't work, but did I listen? NOOOOO...LOL...he had the last laugh...LOL

I would have tried to put it back together...LOL...I had to fix a lot of the rim on my dish it was all beat up from the ride down from the heavy-handed trackhoe operator...LOL

 

[whatchel1]

I was too. In fact I would have bet MONEY on it. But I was wrong as teats on a bull. I did exactly what you describe first, The First Hillbilly (phlatwound) told me it wouldn't work, but did I listen? NOOOOO...LOL...he had the last laugh...LOL

I would have tried to put it back together...LOL...I had to fix a lot of the rim on my dish it was all beat up from the ride down from the heavy-handed trackhoe operator...LOL

I looked at seriously trying to put the piece back in but it was at the very bottom where the bottom feed support goes. Didn't have the giant heavy duty arm coming off the mount like the one in the project here. So support arm was a problem plus edge of dish was compromised and strength as well.

 

[pendragon]

Putting on a C/Ku combo feed of any kind will compromise Ku performance. I'm with phlat on making 1.8m Prodelins Ku-only. They do that job incredibly well.