Best Way to Receive Whole Ku Arc With Fixed Dishes?

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I vote for pointing it at 95, and see what kind of slice of the arc you get. For some reason I have a hard time seeing a 6' getting more than 6birds 2degrees apart, but then I never tried it either. Anole's math was impressive (I can barely understand a tire pressure guage lol) . Really curious to learn what the prodelin can do though, its a fine looking dish.


Don't worry Brother they lost me a LONG time ago. :)

I just watch and try to learn.
 
Well my wife didn't like where I had planted the mount for experimentation and testing. I tried to explain that it was only there temporarily, but she made mention of the fact that my temporary can turn into 6 months and I couldn't argue with that kind of logic.

So my son and I got out in the snow flurries and took what we had assembled apart and moved it over with the other "testing" dishes just to make her happy. :eek:

It is supposed to sunny and in the 40's tomorrow. Big drop in temps Monday, so I am going to try and get it re-assembled, tightened down etc. tomorrow afternoon.

Pic of new temp spot:

non-pen-mount-moved.jpg
 
same prodelin!

i just got the same prodelin! are you going to fixed dish ku lnb for the thirty degrees on this? my god, the lnb support arm is strong enough. the thing could hold 100 pounds...it is made of IRON. i am just going to motorize it and use it as a combo ku c, which looks like it might be troublesome, so i might just motorize my prodelin 75c for the ku, and keep the 6 foot for the cband. maybe some one can tell me if i can use a garden variety motor for the 75 maybe like an sg2100. it is superlight, but the mounting hardware is IRON. of course i live in los angeles, and a forty mile an hour wind is considered a hurricane, so maybe i can mount the 75 on my pipe mount with the sg2100?

thanks as always to the bold that go the extra mile, risking failure and board ridicule for the magical moment when you get a peak signal and the picture pops!
 
how wide IS it ?

English -
I thought you said in another thread, that you'd put multiple fixed Ku LNBs on the 6' Prodelin.
What I thought you could offer to this conversation was how wide a swath you'd found reasonable.
(I'm guessing from 129° in the west to ??? in the east, 99°?)
Linuxman is going to run some tests pretty soon, and I wanted a little preview! - :cool:
 
multiples on the 75

i put the multiple lnb ku on the 75, it was fine, but now i will just motorize the prodelin 75 thanks to the board members who modded the primestar to have a motor. the 6 foot prodelin is next, but i can't believe that linuxman is still testing...crazy if he can get fixed lnb on a c, that is mind boggling, but thanks for all the input as always, anole.
 
The dish is now in it's new temporary testing home. :)

The manufacturer put a lot of money into building the mount for this dish. I used the little bubble to make sure the mount is plumb. The azimuth scale is off because the dish was originally pointed off to the west somewhere for Hughes network and I didn't want to go through the routine of re-adjusting the rod etc.

It needs a good scrub, and I may even paint it if it performs like I want. :D

Got to find that thread in the C-Band section where the guy painted a fiberglass BUD with latex paint of some kind using a roller. It turned out beautifully. :)

The LNBF support arm is inside for me to start making a bracket.

Here are the new pics:

temp-home-testing.jpg prodelintemp-home-testing.jpg prodelin-adjusting-rods.jpg prodelin-azimuth-adjuster.jpg prodelin-plumb-bubble.jpg
 
damned big piece of paper !

Here are some outrigger LNB locations for when you are aimed at the 91° bird at your true south... not that TS really matters. :rolleyes:

Requirement was to go ±12° and ±15° on bird orbital locations.
That doesn't translate too well into actual aiming angles, so let's see what we can do.

Code:
[FONT=Fixedsys]..       
               degree  inch   [/FONT][FONT=Fixedsys]for 6' Prodelin dish[/FONT]
[FONT=Fixedsys] orbital  loc   offset  offset     skew
 74°      H:   +26.2°  +22.95"   -19.22[/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +3.0°   +2.72"

 79°      H:   +18.8°  +16.75"   -13.64[/FONT][FONT=Fixedsys]° [/FONT]
[FONT=Fixedsys]          V:    +1.4°   +1.27" 

 83°      H:   +12.7°  +11.4"     -8.89[/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +0.6°   +0.54

 91°      H:     0.0°    0.0"    bore sight 
          V:     0.0°    0.0"
 
101°      H:   -15.8°  -14.15"    +13.21[/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +1.4°   +1.27"

105°      H:   -21.7°  -19.22"    +17.74[/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +2.5°   +2.26"

[COLOR=Blue]107.3[/COLOR]°    H:   -25.0°  -21.97"    +[COLOR=Blue]20.21[/COLOR][/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +3.4°   +3.08"
...
[/FONT]
As always, you are welcome to verify the calculations.
They are not hard, just tedious.
And a pain in the butt to enter, as the editor fights with ya!
 
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Now that we are getting down to the nitty-gritty of actually trying to build a bar/bracket to set on the support arm and line up LNBFs, I have a question or two naturally.

Being the observant type. :rolleyes: I have noticed a couple of things.

First of all this dish was located about 15 miles from me, so elevation etc should all be about the same. When this dish was set up on the roof over a year ago, it was pointed off to the southwest wherever they used to get their internet access from.

The elevation scale which hasn't been changed since it was setup shows about 46 degrees.

My true south is about 45 degrees. If this dish was pointed say at 110W which is approx 40.7 degrees elevation, I am wondering if the elevation was adjusted to compensate for the monster LNBF that was on the dish.

Reason for all this is that if I am going to build a bar to put LNBFs on, do I need to go all the way up the 5-3/8" shown in the picture below, or will a couple of inches above the support arm be more in line with the original off-set angle?

I have contacted Prodelin, and they are going to try and find a manual and spec sheet for this dish and send it to me.

Take a look and let me know what you think?

prodelin-elevation-scale.jpg prodelin-side.jpg
 
elevation angle of Prodelin

If you are hung up on using that elevation gauge, you'd better calibrate it.
Maybe it's right, and maybe it's wrong, and maybe your dis-assembly of the LNB arm left you off a few degrees.

I'd point you to a post I made a while back, about finding the focal point of a dish, given the mount was accurately calibrated.
But here, the question is about the calibration. . .

I'll take a look for some documents.
The mfgr's web site is full of PDFs... (see below*)
Should give the dish's offset angle, and a place to measure from, if not off a line across the face of the dish.

I believe you can put an angle finder on the lower LNB support in that short dog-leg at the bottom.
That should be the actual elevation angle of the dish.
But, that's from memory.
Let me mark-up a picture . . .

edit: added reference picture
And I would put the TS LNB at the 5 3/8th inch height.

* FindMeProdelin_1.8mDish.txt
1.2 1.8 meter dish / mesh ku offset ka rx/tx Andrew Channel Master Prodelin Solid 1 meter
http://www.gdsatcom.com/prodelin.html
 

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If you are hung up on using that elevation gauge, you'd better calibrate it.
Maybe it's right, and maybe it's wrong, and maybe your dis-assembly of the LNB arm left you off a few degrees.
Me, hung up? :yikes:

I'd point you to a post I made a while back, about finding the focal point of a dish, given the mount was accurately calibrated.
But here, the question is about the calibration. . .

I'll take a look for some documents.
The mfgr's web site is full of PDFs... (see below*)

Should give the dish's offset angle, and a place to measure from, if not off a line across the face of the dish.

I believe you can put an angle finder on the lower LNB support in that short dog-leg at the bottom.
That should be the actual elevation angle of the dish.
But, that's from memory.
Let me mark-up a picture . . .
I went out and measured the bottom side of the dog leg, and it shows 45.1 degrees. :)

edit: added reference picture
And I would put the TS LNB at the 5 3/8th inch height.

* FindMeProdelin_1.8mDish.txt
1.2 1.8 meter dish / mesh ku offset ka rx/tx Andrew Channel Master Prodelin Solid 1 meter
http://www.gdsatcom.com/prodelin.html

I think you are probably right. From the manual they sent, see below, it appears the dish was designed for that mammoth LNBF.

The email they sent said the F/D was .6, and the focal length was 43.2. That information is incorrect as I measured 52 inch focal length, and from the documents I have found online show a F/D of .8.

EDIT:
The documents all say 22.3 degrees offset.

The F/D really doesn't matter as it is what it is. :)

I can use a flat piece of steel with enough overhang forward and with two holes drilled in it to correspond to the two slots in the support to allow for adjusting focal length.

I then need to have a vertical assembly to set the mounting horizontal rod on which will allow the feed-horns of the new LNBFs to be at the same height (5-3/8") that is the height of the current beast.

See pic and manual:

support-slots.jpg

View attachment 4096-132.pdf
 
I didn't want you guys to think I was sloughing off on this project. Just had a couple of other things to attend to. :)

I also wanted to think it through a little more. Got a couple of days of frigid temps to work on it, with 30's by Saturday and 40's Sun through Tuesday. Might even be able to catch a signal by then. :cool:

Today I made the first steps towards assembling my LNBf rod and support plate to put on the support platform for the Prodelin dish.

The center of the LNBf is at 5-3/8" above the support plate, and as you can see by the vertical line on the support arm, the front of the LNB is right where the old one used to be.

The flat support plate will slide in or out about 1/2 an inch. The slots can be expanded or the two holes down through the plate could be turned into slots really easy for more in or out if needed.

The bar is 1" square steel tubing, and the bolts are all 1/4 inch, so I don't think it will go anywhere. :eek:

The bolts through the bar are 4 inches long, and the bolts through the LNBf holder are 3 inches long.

It is totally adjustable for plumb and everything else for that matter, once I get it on the dish.

I want to try and use some of my dual output Primestar lnbfs that I will be taking off the Primestar dishes in the center, and use the ones I have to buy on the ends and on the Primestar dishes.

My plan is to put in a 6" slot - 1/4" solid, another slot - solid, repeat to the ends of the rods.

How far out from center should I attempt my first slight bend?

What do you think so far?

Here are some pics:

center-lnbf-on-support-bracket-rod.jpg center-lnbf-on-support-bracket-rod-side.jpg center-lnbf-on-support-bracket-rod-side2.jpg
 
I have seen where people have curved there mounting rod to the shape of the dish to be mounted to and then filp it around so the curve faces the dish. But I do not know how you could do it with the box tubing.
 
My plan is to put in a 6" slot - 1/4" solid, another slot - solid, repeat to the ends of the rods.

How far out from center should I attempt my first slight bend?

What do you think so far?

Looks good so far. As far as where to bend, I think what gremlin411 suggests is the best way to attempt it. Figure out how far the ends have to be curved from the centre and then divide the distant into whatever segments are easiest to do. I'd also hold off on drilling the slots for now, it might be better to mount the bracket and then do a handheld test for the various satellites, mark their rough position and then drill say a 1 1/2" slot to allow some leeway either side. I would think that a 6" slot followed by a 1/4" solid would weaken the bracket way too much, smaller slots and as much solid as possible would be best.
 
minimum spacing for far LNBs

You already have numbers for 105° and 107.3° birds.
Here's some 72° numbers to go with the 74° listed above.
As you can see, the horizontal spacing is still a gigantic 2¾", and much more near center for 2° birds.

Code:
[FONT=Fixedsys]..
               degree  inch   [/FONT][FONT=Fixedsys]for 6' Prodelin dish[/FONT]
[FONT=Fixedsys] orbital  loc   offset  offset     skew
 72°      H:   +29.0°  +25.21"   -21.33[/FONT][FONT=Fixedsys]°[/FONT] 
[FONT=Fixedsys]          V:    +3.8°   +3.44"

'"[/FONT]
On another matter, do consider that the feedhorn you've shown for your central or True South satellite, is for an elliptical dish.
For this dish, round feedhorns are proper, though I think you'll still blow the doors off that central LNB!

AND, I also agree that the distance from the center of focus on the dish to the TS feedhorn should be duplicated for the wing LNBs.
That suggests the side LNBs be both pointed toward the center of the dish, AND pushed toward it.
At this time in testing, I feel you should come to grips with those questions, as well as how far a spread you can get, and onlly THEN consider building the final LNB mounting bar.
 
Thanks Gremlin, Keith, and Anole!!!

I will take the bar to the dish today, lay it against the dish and get some measurements every 4 inches or so to get an idea of how far the bar needs to be bent. It is a whopping -2F degrees with a wind chill of -12 right now with a high expected of 8F, so most of what I do will be inside. :eek:

As Keith said, that will also help me determine how far between each bend spot. I will have some room to slide the LNBFs in using the holders, so it might not real critical to get the bend just right.

I agree with Keith's assessment that longer slots may weaken this tube too much. I am already considering that this tube walls may be a little too weak already. It is easy to work with, but after writing last night, I checked and did find some movement possible already. I think it might not be possible to drill etc. once it is mounted so I might have to find a heavier tube. :)

With the spacing allowed between LNBFs, I might try a 3 inch slot with an inch of solid and see where that gets me.

I agree about the eliptical feed-horn not being proper Anole, but as you say, I don't think it will matter much on the even the center 3 LNBFs. :)

Thanks for your help and suggestions. We'll see what we get done today. :)
 
why not toss a c lnbf in?

i marvel at the creativity...of course i think i might like to follow your idea, so i watch anxiously at each development. could you toss that c band lnbf w feed horn at the center to add some bud spice to the ku krazyness? kudos to the effort, and the comments of the board- especially the bend of the bar to fit focal length. wow!
 
Made some progress today.

After thinking over the comments here, I decided to not use the original tube because it was just too thin walled.

Went to the old hardware store today where I always go to find what can't be found anywhere else, and sure enough, they had some 1 inch square tubing with 1/8" thick walls. They even cut it off to the length specified by me. :)

After looking at Anole's figures, if I even wanted to try and get 20 degrees out, I needed a long enough rod to hang the lnb on. If it doesn't work out, I can always cut it back to a shorter size.

Got home, and my son and I took it out to the dish and took some measurements. Came inside, and made a template just to see what was what. :D We were only out a short time, but it was cold.

At the farthest distance at the center, it is only 4-1/8 inches.

I contacted a buddy of mine, and we are going to see about getting it rolled to the proper angle on Saturday. The same guy has a plasma cutter which will do a great job on making slots.

I have a couple of pics, sorry for the quality. I think I was still cold when I took them. :eek:

My big question is:

Considering the much thicker walled tubing, do I need to have 1 inch of solid between the slots?

We are talking the difference between 5 inch slots, or 5-1/2 inch slots except in the middle.

I know 1 inch of solid between the slots will be plenty stable, just wondering if I can get by with 1/2 inch of solid?

Take a look and let me know what you think please. :)

angle-of-bend.jpg

thicker-tube.jpg

EDIT: Forgot to reply to english2fourth.

i marvel at the creativity...of course i think i might like to follow your idea, so i watch anxiously at each development. could you toss that c band lnbf w feed horn at the center to add some bud spice to the ku krazyness? kudos to the effort, and the comments of the board- especially the bend of the bar to fit focal length. wow!
Thanks for your kind words.

I could put a C/Ku LNBF at the center, but currently there aren't any dual ouptut C/Ku LNBFs available. Hopefully there will be some dual output C-Band only LNBFs available one of these days.

The guys here are very helpful when brainstorming and coming up with creative ideas, and I thank them very much. :bow:
 
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