123w and 129w with 1 Meter Primestar

[linuxman]

I have been reading with interest the threads above about hanging a second lnb to get both G10 and G27.

I just picked up this week a 1 Meter "round" Primestar. It has a little different arrangement for mounting the LNBf. I was going to make this stationary on G10 anyway, but thought if we could figure a way to put another LNBf on it, I might as well get G27 too!

Here are a couple of pics of the way the original LNBf is mounted.





The bolts holding down the neck are about 1-1/4" center to center, and the bolts themselves are 5/16" dia.

You think it is better to try and use the yoke bolts, or attach to the arm on the right with a clamp or something?

Please, help me out with some ideas to use the existing LNBf and add another one for White Springs.

Thanks,

Fred

 

[Anole]

where to stick that LNB

You may recall that a few months back, there was a thread on putting two LNBs on a big dish in Alaska for Dish.

As an offshoot to that, we had another thread to condense the math to make it easy to locate any 2nd LNB on any dish, for any bird.
You might give that a read, then once you calculate where to put the second LNB, the exact how will be more apparent.
For instance, you'll know both the distance and angle from the first LNB, so you'll know how long a bracket or spacer you'll need.
The only problem I see, is clearing those support arms.

Oh, and what I wouldn't give for a 1m round Primestar.
Lucky find.


edit:
Also... in another thread about a Canadian supplier, we ran across two interesting brackets they had.
This one seems useful.
And this one might be even better.

You've seen what Iceberg does with hose clamps and wood blocks.

And z4ccamaro came up with some conduit hanger brackets which show lots of potential.
Doesn't take much for WhiteSprings - start at post #24 for bracket pictures.

 

[linuxman]

Thanks Anole,

I do recall that thread and am off to read it now. I'll check out the other links too, there should be a fairly easy way to do this, but knowing where to put it will help.

I hunted for months before finding this baby, and I think it is the only one within a 25 mile radius. Haven't seen any others. Most of the 84e's I've seen, I now own. I was just thankful to get this one.

Fred

 

[gabshere]

i've found four in a 25 mile radius , i have 2 of them and the other two are waiting for me

i have a idea how to mount the second lnb but will read the other post , i do agree that it will have to be a lower or higher mount due to the support arms.

i do have several feedhorns that fit this dish so hopefully i will get to test it soon.
this is the dish i have mounted on my motor and currently have motor problems due to the coax connection on the sg2100 came loose@ the motor.

 

[linuxman]

Well it would help a little if I knew what the math symbols were.

I have a BA degree in Religion with a History Minor, and 23 hrs towards a MDiv degree. can read three different languages, can program in php and html, but I flunked algebra twice in High School, and finally passed general math, then only took general math in College to get the above degree. I just have a mental block with math and formulas. I can tell you how much profit I am making though.

I know that if I set G10 in the center on the original LNB, I will have to set the one for G27 on the East side of the center to receive from the offset West, and because the elevation is lower on G27, the LNB will have to be higher than the main one. The support arms may not be much of an issue.

Now if I could only work the formula, I'd be set.

Fred

 

[linuxman]

I had to go up and get my tools off the roof because another storm is coming. While up there, I measured the Focal Length of the 1M dish.

Using a plane that runs parallel to the throat of the LNBF and measuring from the center of the eye to the center of the 4 bolts, the Focal Length is 28".

Horizontal offset: focal_length * sin(new_orbital_position - old_orbital_position)
Vertical offset: horizontal_offset * tan(my_skew_angle)

I'll go as far as I can, and you guys jump in and help out.

123W: azimuth=226.9 elevation=33.9
129W: azimuth=233.2 elevation=30.1

Horizontal offset = 28" (multiplied by) sin(new_orbital_position - old_orbital_position)

Vertical offset: horizontal_offset (multiplied by) tan(my_skew_angle)

Now if I only knew what sin and tan were besides bad things and nice looking babes, I would be all set.

Fred

 

[linuxman]

Al right, after staring at the formula above and doing some quick searches on sin and tan and angles on google, I have come to the conclusion that the * in the formula can't possibly mean multiplied by, so here is my next try.

123W: azimuth=226.9 elevation=33.9
129W: azimuth=233.2 elevation=30.1

Horizontal offset = 28" (divided by) sin(new_orbital_position - old_orbital_position)

Vertical offset: horizontal_offset (divided by) tan(my_skew_angle)

Horizontal: 28" (divided by) sin(6.7) = 4.44"
Vertical: 4.44" (divided by) tan(3.8) = 1.17"

I have no idea if it correct or not, but it at least is an attempt.

So 4.44" to the East of the center LNB and 1.17" up from the base line.

Tell me if I am right or not? Please?

Fred

 

[BKP]

Hey, Fred...

That's just like my Primestar dish.. I'll be following this thread incase I actually get somebody to hook up mine.. I was thinkin' about a second lnb, also..

Did you have any problems with the junction block screws..



Later, Brent

 

[linuxman]

Hey Brent!

Long time no talk!

Did you have any problems with the junction block screws..

Sorry I don't know which screws you mean by junction block.

Fred

 

[BKP]

Yes, I ain't been around much...

The two screws holding the lnb on.. Junction block is the official name according to Dow Electronics, Hahaha...


Later, Brent

 

[linuxman]

The two screws holding the lnb on.. Junction block is the official name according to Dow Electronics, Hahaha...

They were tight, but I screwed them out ok with a big screwdriver. I am going to try and get a socket to fit them though. I might have to use them to put some sort of bracket on. But I loosened them up to set the skew for G10.

Fred

 

[Anole]

let me try calculating that

It's always good to get two views of the same problem
If the solutions match, then we both screwed up.

Here's the proper math from the MJFlash thread:

[FONT=Courier New] Horizontal offset = focal_length * sin(dish_azimuth - new_azimuth)
 Vertical offset = focal_length * [I][B]sin[/B][/I](dish_elevation - new_elevation)[/FONT]

You may have gotten confused if you read back through the original Alaska threads.

Here's my estimate for where you are and what the raw numbers should be:

[FONT=Courier New]                      Saint Louis, MO 63147
          Latitude 38° 42.834'N Longitude 90° 14.250'W

                         Sat Name Sat Lng Az(t) Az(m)   El  Skew
----------------------------------------------------------------
                       Galaxy 10R  123.0W 225.8 226.4 33.8  34.0
 Intelsat Americas 7 / EchoStar 5  129.0W 232.1 232.7 29.9  38.0[/FONT]

I used St. Louis zip, and az/el from Satfinder by P Lutus.
If you use other numbers and come anywhere close, declare it a success!

[FONT=Courier New] Horizontal offset = 28" * sin(225.8 - [/FONT][FONT=Courier New]232.1[/FONT][FONT=Courier New]) = [B]-[/B]3.0725 "
   Vertical offset = 28" * [I][B]sin[/B][/I]( [/FONT][FONT=Courier New]33.8[/FONT][FONT=Courier New] - 29.9 ) = [B]+[/B]1.9044 "[/FONT]

I'm sure I've screwed up on which is higher/lower or east/west, but we know those things by a fundamental understanding of the dish optics.

Anyway, run through your real numbers.... and I'll double check mine... and we'll see who flinches first. :up


edit: I put 129º Whitesprings as the secondary, and updated the numbers above per MJFlash's formula.
Since you can get Whitesprings on pretty much any tiny dish, it's not the primary LNB to be aimed with the mount.
So now, the sign of the numbers should be correct for the secondary 129º LNB

more:
I looked up the Andrew 1.0 meter dish, and think this is it.
Shame though... doesn't say the focal length.

_____________________
Invacom SNH-031, SKY Mexico DVB321-3, Fortec 36", Satpros DSR500s, Mercury II, Twinhan 102g & StarBox
Thanks to Sadoun & SatelliteAV for good deals, & SatelliteGuys for good reviews.

 

[linuxman]

Thanks Anole!

I just took a stab at it. I really don't know if I did the formula correctly or not. No way for me to tell.

Fred

 

[mikekohl]

You're making this too complicated; which is hard to believe considering
someone's aversion to math!

Look at the front of the dish---after first tuning the main LNBF to Galaxy 10.
From St Louis, 129 West will be to the right and slightly higher than the center
LNBF. (It works like a mirror. with lower elevation of 129 translating into a
higher "bounce"). Simply pretune your receiver or meter to the TP for White Springs TV, and wave a Ku-band LNBF in front of the Primestar dish, to the right
and above the existing LNBF. This is your "rough-in" of whether it will work or not.
Then go back to the calculator to see if it can explain why it works there!
Reality usually works every time.

My method takes less than five minutes, using these general principles.
(Unless you like running a calculator for a much longer time and possibly
getting an incorrect answer).

 

[linuxman]

You're making this too complicated; which is hard to believe considering
someone's aversion to math!

Hey Mike,

That's what I said in post #5:

I know that if I set G10 in the center on the original LNB, I will have to set the one for G27 on the East side of the center to receive from the offset West, and because the elevation is lower on G27, the LNB will have to be higher than the main one. The support arms may not be much of an issue.

I do like to understand how things work, and why they work, and I actually tried to work a formula for the first time in over, well let's just say several years.

I just need a simple way to hang it on there. I have always used your method when adding a dbs lnb.

Now I have a number to work from to help prepare a custom adapter.

By the way, I see you have several slick looking adapters for 84e's on your site. I don't need anything elaborate for this as I am just going to use one LNBF besides the original one. I'll give you a call and see what you have for this one.

Thanks for everyone's help, and thanks for running the numbers Anole, and for trying to stretch my brain a little!!

Fred

 

[techie]

It's raining dishes around here

Just a quick note to say that it appears to be raining free dishes in my rural area. I did my first KU FTA install recently, and since then I've located (and was given) 2 Channelmaster 36x27 dishes, and my lastest find was a Primestar like you obtained Linuxman. I was driving around the village and I saw one laying on it's back, loose on the ground (without a pole). I stopped in to inquire, and the owner gave it to me in a flash. Since I already had another Channelmaster in my little Nissan pickup, it was overflowing with dishes on the way home. :up In addition, I have my eyes on several more in the same area, and I've been offered another free BUD system to compliment the free 8.5 Birdview I was given recently. As they say, "when it rains, it pours". Anyway, I digress... I'm happy to see that the Pimestar dishes are in demand. I plan to point mine to 129W tomorrow. It seems that rural areas in the midwest are good hunting grounds (as well as cities). Good hunting to those still looking.

 

[linuxman]

Nice find Techie!

The 1M Primestars are hard to find around my area. There are a lot of 84e's and some 75e's like your first one, but the big guys are hard to come by.

Same goes for the Birdviews. Few in number, but great in quality!

I only hope more people get out there and hunt for dishes. Keeps them out of the scrap yards and landfills.

Fred

 

[kstuart]

You've seen what Iceberg does with hose clamps and wood blocks.

I have used lettuce ties - those big blue twist ties that keep the lettuce leaves together.

I was considering starting a thread with pictures called " Lettuce Get More Channels "

But over the long weekend, I replaced them with nicer looking twist ties.

 

[linuxman]

Hey Kstuart,

I ordered some pieces from Mike Kohl last evening that should help me add this second LNBf to my P* 1M. He has some interesting pictures on his website about how to add LNBFs, but doesn't sell the complete kit any longer because the parts can be bought at Lowes or Home Depot.

I'll post pictures when I get mine assembled, but probably won't have his parts until Friday or Saturday.

Mike is always an interesting guy to talk to, and has done about anything and everything there can be done to a satellite dish at one time or another.

Now that I have some numbers for a general location, I am looking forward to the experiment.

Fred

 

[Anole]

... some interesting pictures on his website about how to add LNBFs, ...
... the parts can be bought at Lowes or Home Depot.

Wow, those pictures really are worth 1,000 words, aren't they?
I especially like the horizontal bar over the Primestar LNB mounting bolts!
That's quite inspired!

Now that I have some numbers for a general location, I am looking forward to the experiment.

Yea, you know how long a screw to buy.
I am looking forward to your next set of pix! :up
.... and how close you find the hotspots to our calculated locations.