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

[phlatwound]

First of all I would like to thank Linuxman for passing this dish and mount along to me back in July, much appreciated, it's found a good home.

Second I would like to thank Pendragon for actually figuring out how to breed these 2 units, and for climbing up on his roof to give me some measurements.

Ever since I put a 1.2m Prodelin offset on a Birdview H-H mount a couple of years ago I have been looking for a Prod 1.8 to attempt same with. Then when Linuxman offered me not only a Prod 1.8, but an AJAK 180, my mission started to form. The final piece was when I discovered Pendragon's thread showing how he had joined this dish to the AJAK mount.

http://www.satelliteguys.us/free-air-fta-discussion/237608-1-8-dual-axis-prodelin-conversion.html

Here is a few pics documenting my progress to date, with the reflector installed. Next step, to install an LNBF and see if I can get this beast hugging the Clarke Belt.

 

[Tron]

Great job and pics, Phlatwound! I'd love a 1.8M Prodelin!

 

[mjac]

Impressive! Nice work.
I am smoking on a similar project although on a much smaller scale.

 

[Cadsulfide]

Way cool, all those weak s2 signals will soon be on a TV near you!

 

[phlatwound]

Thanks guys, this has been a fun project so far.

I hooked up a CS6K & G-Box, put a GeoSat SL2 Bullet on, and within about 10 minutes I had found signal on 93W, did a quick peaking there and was tracking well from 72W to 127W with no further adjustments.

Going to have to lose a few small trees this winter to get 30W LOS with this dish.

I'm getting approximately 20.5 counts/degree with a G-Box on the AJAK 180, and the AJAK handles the weight of the Prod 1.8m very well.

Next step is to hook up an OpenBox and see how it does with S2.

 

[Anole]

Did yours come with that 3 pound coffee canister full of electronics (and feedhorn) ?

I hooked up a CS6K & G-Box, put a GeoSat SL2 Bullet on, and within about 10 minutes I had found signal on 93W, did a quick peaking there and was tracking well from 72W to 127W with no further adjustments.

Are we getting good, or just lucky?

I'm getting approximately 20.5 counts/degree with a G-Box on the AJAK 180, and the AJAK handles the weight of the Prod 1.8m very well.

Yea, it's a pretty stout mount, easily capable of slinging the likes of that dish.

Are you happy with the count for Ku , or is an improvement needed?


Consider yourself quite lucky.
It's hard enough to get either the Prodelin or the AJAK mount.
Rare is the member who has both to play with. - :up

 

[phlatwound]

Did yours come with that 3 pound coffee canister full of electronics (and feedhorn) ?

No, not the 1.8m but I do have one of those from my Prod 1.2m, not sure if it is identical but they look very similar from what I have seen.

Are we getting good, or just lucky?

Yes.

Are you happy with the count for Ku , or is an improvement needed?

I think the level of accuracy provided with that count is more than adequate for Ku.

Consider yourself quite lucky.
It's hard enough to get either the Prodelin or the AJAK mount.
Rare is the member who has both to play with. - :up

Oh yes, indeed. Fred fixed me up bigtime. I have only seen 1 AJAK around my parts, and haven't been able to make it follow me home. Of course there are lots of 1.8m Prods around, but again, none of those have found their way to my place yet.

 

[Anole]

Did yours come with that 3 pound coffee canister full of electronics (and feedhorn) ?

No, not the 1.8m but I do have one of those from my Prod 1.2m,
not sure if it is identical but they look very similar from what I have seen.

I think Pendragon had the right idea, recycling the old feed with Ku scalar to the big dish.
As if you didn't have good enough signals now, you might think about bolting a Primestar (or other) LNB to that feed, and test-driving it.

 

[phlatwound]

I think Pendragon had the right idea, recycling the old feed with Ku scalar to the big dish.
As if you didn't have good enough signals now, you might think about bolting a Primestar (or other) LNB to that feed, and test-driving it.

I agree and will explore that idea when I get a chance, need to find that feedhorn first.

Pendragon mentioned some "simple adapter machining" to mate that Prod horn up to a C120 pattern, not sure if that is something I could do or not.

As you can see from my pics my "machine shop" is pretty low-tech (no-tech?).

 

[pendragon]

Looks like all is going well so far.

My Prodelin Rx/Tx electronics package had a lot of internal plumbing crammed into fairly small spaces. Since I never planned to use most of this, I stripped it down without paying any attention where the pieces came from. The scalar itself was pretty simple, but was machined for a WC75 flange instead of the C120 I needed. You can buy adapter plates for this but the best source was overseas and the price was more than I wanted to pay. From the plumbing salvage pile I found a spacer plate that was around 1cm thick and drilled for WC75 on both sides. I added some holes to match C120 and that was good enough.

This would have worked fine to adapt the feed to my Invacom LNB, however I would have had to fashion a rather odd LNB holder to match the Prodelin's feed platform. The electronics box mated perfectly with the platform's mounting and was driven by a servo for skew. If the box and servo weren't so massive, I might have tried to incorporate them. But I wanted room to play with side car LNBs, so that was a non-starter.

What I decided to do was saw off a square portion of the front face of the electronics box. I then used a simplified version of the Rube Goldberg pieces from the original. This required a few more holes and some shims to tighten the assembly, which had rotated freely in the platform mount, into something with plenty of friction. I was able to patch this all together with o-rings at the critical interfaces so it should be watertight. There was an angle scale in front of the original electronics package that I adapted into a skew scale for manual adjustment. I can rotate the feed by hand, but it's tight enough that it won't move on its own.

I'm not sure the above will be of any help to others because I have not seen this package on other local Prodelins. Everything fits nicely together and makes a compact assembly, but I truly hate taking it all apart. Especially on the roof. So until the LNB breaks, I probably won't have any pictures to offer.

 

[phlatwound]

........... The scalar itself was pretty simple, but was machined for a WC75 flange instead of the C120 I needed. You can buy adapter plates for this but the best source was overseas and the price was more than I wanted to pay. From the plumbing salvage pile I found a spacer plate that was around 1cm thick and drilled for WC75 on both sides. I added some holes to match C120 and that was good enough. ......

Thanks pendragon, I now understand what you did there.

Here are some pics of what I have: Prod. 1.2 Rx/Tx unit w/horn, Prod 1.2 horn, NJR2119F (Primestar) H/V output LNB. If I was to go to the trouble/expense of making/procuring an adapter to use this feedhorn I think I would go the same way you did, with the Invacom 4-output (2 circular & 2 linear) C120 flanged LNB.

There also is a pic of a C120-to-WC75 adapter, maybe the same one you found in your searching (from Swedish Microwave AB)? Do you remember what the price tag was on the adapter plate you found? I'm sure it's more than I want to expend, so far my budget for this project has been the cost of a tank of gas, and Fred and Terry's lunch. All metal, hardware, "machine work".......even the "welding" used to this point has been sourced from our 100 acres.

Unfortunately, without the proper equipment (and knowledge of its use), I have no way of really tuning a dish to it's peak, you can only do so much with the meter on an FTA receiver, to say nothing about being able to determine signal loss in the rest of my distribution system.

Hmmm.......maybe I need to be entering Brian's "S2 Digital Sat Meter w/Spectrum Analyzer" giveaway? As soon as I can come up with a school story that is actually printable I may do that.

 

[Anole]

- I was thinking that Pendragon used a 4-output Universal LNB, not the QPF-031, but either would cost an arm 'n a leg.

- was actually serious about using an old two-output Primestar soupcan; the type marked with H & V outputs and feeding 'em to a multiswitch.
It's something you might have on hand.

- if you can get a proper picture of the adapter plate you need, I'm sure a number of members have 'em.
Don't they come on round Primestar dishes with the long feedhorn?
Or maybe it was on the dishes that sported single-polarity LNBs?
It's something I remember being discussed on the forum several years ago, and I never did understand what they were all about.

 

[phlatwound]

I was thinking that Pendragon used a 4-output Universal LNB, not the QPF-031, but either would cost an arm 'n a leg.

Anole, you may be right about that, I assumed that his LNB was a 4-output lin/circ. I will re-reread what he posted.

- was actually serious about using an old two-output Primestar soupcan; the type marked with H & V outputs and feeding 'em to a multiswitch.
It's something you might have on hand.

- if you can get a proper picture of the adapter plate you need, I'm sure a number of members have 'em.
Don't they come on round Primestar dishes with the long feedhorn?
Or maybe it was on the dishes that sported single-polarity LNBs?
t's something I remember being discussed on the forum several years ago, and I never did understand what they were all about.

I do have several of those P* H/V soupcans, that is the 2nd of the 5 pics I posted above. If I was to go that route I would be looking for an adapter plate to adapt the pattern of pic 1 (WC75-pattern Prod feed horn) to the pattern of pic 2 (NJR aka P* H/V LNB). I definitely want the capability of feeding a multiswitch, and either of these options (Invacom or P*) would provide that.

So you think there may be an adapter plate to mate the P*/WC75 combo? I have never seen a P* dish in this area bigger than an 84E, they are all ovals here since we were in the center of the footprint I guess, nothing bigger was required.

Thanks for the ideas, that is another direction I could go and I think it would work well......just need an adapter plate.

Edit: I just realized something....I had assumed that the P* bolt 4-hole bolt pattern was different than the 8-hole C120 pattern, but maybe they are the same diameter and spacing (just with 4 holes instead of 8)?

 

[pendragon]

Your electronics/feed package looks much newer than mine did. The one I had was a giant rectangular box that was barely able to clear the Prodelin feed platform when the skew was adjusted by the servo. Everything was inside: the plumbing, LNA, BUC and a bunch of plug-in cards. The scalar looks the same, but the adapter plate may be different. Wandering down the feed is where our units start to diverge. Nevertheless the concept of modifying the plate to fit a C120 LNB should be similar. Perhaps yours is even properly drilled.

The adapter plate I found in Europe was something over $100. I'm sure it's very nice, but not enough to offer any performance advantage. The LNB I'm using is an Invacom QTF-031 which is a universal Ku design with four fixed outputs. I wanted this because I wanted to use this dish for a lot of low elevation work. At least it is low in Denver. Invacom makes a similar LNB with four switched outputs, but it costs more and I had no use for it as my LNB directly feeds a 4x8 switch. I couldn't find a supplier on this side of the pond for the Invacom, but it wasn't outrageous having it shipped from Europe. I actually acquired two of these with the other on my dual-ortho feed (the so-called Frakenstein dual-ortho). That one is targeted at my Birdview project.

 

[pendragon]

Unfortunately, without the proper equipment (and knowledge of its use), I have no way of really tuning a dish to it's peak, you can only do so much with the meter on an FTA receiver, to say nothing about being able to determine signal loss in the rest of my distribution system.

I do almost all of my dish tuning with a simple squawker meter, and by ear at that. Once in a while I use my First Strike meter to verify I'm on the right bird or to check skew. It's nice to have a bench spectrum analyzer as a backup, but mine would be no fun to drag outside, let alone on the roof. When I need something accurate I often just use a PC tuner on Linux, that I can remote from a server inside to a laptop on the roof.

Expensive test gear is nice, but hardly essential for most FTA needs.

 

[phlatwound]

Your electronics/feed package looks much newer than mine did. The one I had was a giant rectangular box that was barely able to clear the Prodelin feed platform when the skew was adjusted by the servo. Everything was inside: the plumbing, LNA, BUC and a bunch of plug-in cards. The scalar looks the same, but the adapter plate may be different. Wandering down the feed is where our units start to diverge. Nevertheless the concept of modifying the plate to fit a C120 LNB should be similar. Perhaps yours is even properly drilled.....

I did a little more disassembly on my Rx/Tx unit and found this little item. Until I figured out how to get that plastic cover off there I had though that this piece was part of the larger unit. Is this plate the same or similar to what you modified? This one isn't properly drilled for the P* hole pattern......yet.

 

[phlatwound]

Here is a pic of the dish looking @ 125W. I am using Linuxman's ingenious multi-LNBF mounting bracket (he used it for a fixed installation of this dish) and the GeoSat Bullet LNBF.

I will build something else when I get my new hybrid LNB/feed assembled but it was nice to have this one to start out with, made it easy to find the focal point.

Also swung the dish clear to 61W on the east side (I am at 93W), and scanned in everything there. This is a sweet rig, tracking beautifully, and still basically untweaked.

 

[pendragon]

Sorry, but nothing in your last set of pictures looks familiar to what I had and ultimately threw away. Most of my plumbing employed rectangular waveguides, meaning after the first couple of plates it was completely different. My electronics looked late-1980s at best.

 

[phlatwound]

I have some tree issues to rectify this fall to have clear LOS, but here is what this setup looks like when pointed at Hispasat @ 30W.

I am located at 93W, 30W is about 12.2 degrees above the horizon here.

 

[Anole]

...here is what this setup looks like when pointed at Hispasat @ 30W.
I am located at 93W, 30W is about 12.2 degrees above the horizon here.

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