Determining elevation on an 80CM

[sprig]

Before I ask my elevation question, I'd like to point out that my mast is perfectly plumb in all directions.

When I installed the S1 fixed system (fortec 80CM dish), I set the bracket elevation to 32 degrees (zip 58730 attempting to locate 89W). Using a meter with tone, I could not get any tone over the entire arc.

I started changing the elevation, and finally got tone at 37-38 degrees, and soon found both 93W and 89W; I've since located 103W as well. All elevations for those sats show in the upper 30s on the dish bracket (although by calculation they should be in the low 30s). The elevation markings on the dish are obviously not accurate as advertised.

I am now trying to determine my actual elevation with a level and homemade protractor/inclinometer, in order to accurately set the elevation prior to adding a motor (calculation for dish is 23 degrees for the motor I ordered). Where to I measure the angle, is it on the LNB arm? THe offset is shown as 22.75; do I add that to my inclinometer angle to get the actual elevation? Or do I measure the angle somewhere else?

Are these fortec dishes really trial and error for pointing rather than having accurate scales?

[Iceberg]

sadly the 3 fortec dishes I have owned all were off by 3-5 degrees.

The only one that isnt is the 6 foot dish and there is no actual elevation gauge...its trial and error

[sprig]

Originally Posted by Iceberg

sadly the 3 fortec dishes I have owned all were off by 3-5 degrees.

The only one that isnt is the 6 foot dish and there is no actual elevation gauge...its trial and error

So, should I set the dish angle to 27-28 instead of the calculated 23 for my motor, just for starters, before doing the trial and error?

[wejones]

As Ice said, many people have been reporting the elevation to be in error on these dishes, although I thought it was normally in the other direction. Most people who reported errors had the U-bolt bracket. My Fortec dish, however was pretty close to right on, however I have the pole mount bracket.
However there is another possible reason for the elevation to appear to be off, and that is if the lnbf bracket is bent. If that is the reason for your elevation being off, then it will mean that you don't have your lnbf at the focal point, because there is really only one point where the dish focuses properly. And while on that subject, the answer to your question above is no, the lnbf bracket isn't a meaningful place to measure angles, at least not the part of it that extends out toward the lnbf was not meaningful on my 90cm. I didn't really find any good surface on my dishe that can be used with an inclinometer, however, the closest place I found is on the lnbf arm, but behind the dish where the dish attaches. This wasn't perfect, but it was closer than the part that aims toward the satellite. I would try back calculating the offset angle based on the inclinometer reading at the back of the dish, and if it is significantly off, I'd start to suspect that the lnbf arm was bent. If it is bent, you can still use it as is, but there will be a little degradation of your signal. Might not be enough to notice.

[be236]

Well, I as I've said in the past previous posts awhile back, from my experience with 80cm Fortec dish I got from Sadoun, I found it to be off by about 5 degrees...

Meaning for example, say I calculate my elevation for a particular sat in my location to be 30 degrees, I would have to set the dish 5 degrees higher at 35 degrees, and then I would get that sat.. so basically for whatever calculated angle for any sat I want to get, I just need to add 5 degrees to that and set that elevation from the gauge at back of dish.

[rainman]

the 80cm seems to have to go 3 to 5 degrees higher and the 90cm has to go 3 to 5 degrees lower.

[wejones]

Originally Posted by rainman

the 80cm seems to have to go 3 to 5 degrees higher and the 90cm has to go 3 to 5 degrees lower.

Interesting. My 90 cm with the pole mount was pretty close, but others with the U-bolt report the error. I wonder if the reverse might be true for the 80cm? Ie are the 80 cms that were off, the ones with the pole mount? Ie perhaps the pole mount matches the 90, and the U-bolt matches the 80???
I still think that there is a chance that a lot of these differences are due to bent lnbf arms. I wonder if Sadoun could post data which indicates what the angle of the bend in the lnbf arms is supposed to be for the various Fortec dishes? That way, with an inclinometer, one could determine if this is a problem, and correct it.

[bill190]

I don't think the people who manufacture dishes have ever tried to install one...

It sure helps to have accurate specifications on the dish, especially the offset of a particular dish, yet they don't include this information with the dish! Different offset dishes (dishes with the LNB mounted below center) have different offset amounts. (See below for examples.)

You can find the offset amount of a particular dish at the dish manufacturer's web site or by calling them. Find the specifications for the dish.

Then many dishes which come with elevation markings are not very accurate. Thus best to use an inclinometer. If there is not a surface on the back of the dish which is parallel to the dish, then place a board or straight edge across the front top and bottom edges of the dish to find the elevation of the dish.

Subtract the offset degree of the particular dish (from manufacturer's specifications) from the actual dish elevation (using inclinometer and parallel surface on back of dish or straight edge on front edges of dish) to find and adjust the actual elevation you need.

Examples of different offsets for different dishes...

20.1 degrees - Laminas AS-1500 Offset Dish
21 degrees - Multistar 90cm Ku-Band Offset Dish
22.75 degrees - Strong 80cm KU Band Offset Dish Model SRT-80
24.62 degrees - FORTEC STAR 120cm Model FC120CM
27.6 degrees - DJ 90cm Offset Dish FC90V
28.81 degrees - Janky 81cm offset dish Model No. E80PL(E)
29 degrees - Fracarro SAT12901

0 degrees (prime focus dish) - FORTEC 240cm Prime Focus Dish Model FC08

Offset dish elevation setup explained...
Offset dish elevation angle set up and pointing.

Offset dish explained...
Offset dish antenna - Wikipedia, the free encyclopedia

[wejones]

Originally Posted by bill190

....
Subtract the offset degree of the particular dish (from manufacturer's specifications) from the actual dish elevation (using inclinometer and parallel surface on back of dish or straight edge on front edges of dish) to find and adjust the actual elevation you need.

Examples of different offsets for different dishes...

20.1 degrees - Laminas AS-1500 Offset Dish
21 degrees - Multistar 90cm Ku-Band Offset Dish
22.75 degrees - Strong 80cm KU Band Offset Dish Model SRT-80
24.62 degrees - FORTEC STAR 120cm Model FC120CM
27.6 degrees - DJ 90cm Offset Dish FC90V
28.81 degrees - Janky 81cm offset dish Model No. E80PL(E)
29 degrees - Fracarro SAT12901
....

For a few more examples of dishes that are more common, see:

http://www.sadoun.net/forums/install...sues-data.html

[be236]

My dish is the pole mount. Basically it's the pole (looks like a checkmark physically) where you mount that pole to a wall, and then you take the dish and in the back , there's a neck slot opening where the pole just slides into (like male-female connection (heh)) then you just tighten the screws around that neck... and then supposedly once you are plumb, then you take the elevation reading from the guage meter in the back that shows from 20 deg to 60 or 80 deg I think... so I had to set mine to 35degrees to find the 97w sat listed at 30 degrees for my area... oh well... it's no biggie.. I just have to add "5 degrees" to any expected evelation for any sat I want.

[Iceberg]

I had a 90cm pole mount version on G10..in my area the elevation is 30 but the level meter on the elevation scale was near 25

[elgemcdlf]

While you may think you have it figured out every bit of effort you put into making it work static means nothing when adding in the motor. Everything changes.

[be236]

Yeah, that's why I've been putting off getting a motor, since I hear too many stories that it's difficult relative to static mount and everythings gotta be 99% precise. (heh).. d'oh.

[pmb1010]

dont let that scare you.
A motor makes this so much better by which selection of sats is made possible.

It's not that difficult to set up.

[rainman]

yep and the more sats you receive the more channels you get.