inverted 30 west

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brotherhood

SatelliteGuys Pro
Original poster
Sep 29, 2004
397
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97w/55n
hi guys
Can you tell me what my dish should be at With it inverted for Hispasat .
Also does the lnb skew have to changed ?
IM AT Latitude: 55.7449°
Longitude: -97.8509°
thanks
 
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Skew remains the same.

As for the dish, it really depends on what offset it has.
What brand/model/size do you have?

I think Mike Kohl discussed the simple calculations a few years ago.
Should be able to find with Advanced Search, though I must admit, you might be better off using Google to search SatGuys than the built in engine.
 
I would actually be surprised you can pick it up where you are. it would only be 3-4 degrees off the horizon. Maybe if you are up on a roof above the treeline. Any weather will really drag down the signal. I get a marginal signal here at 6 degrees off the deck and a fairly clear horizon. A bigger dish would help such as a 1.2 or 2m assuming you can get line of sight... I'm at 97W 49N.
-C.
 
How far off the ground do you have to be to pick up on 30w I am still having trouble trying to get that one satellite?

Dan Rose
 
danristheman said:
How far off the ground do you have to be to pick up on 30w I am still having trouble trying to get that one satellite?

Dan Rose

It isn't how far up, it is how many thousand mile East or North East you will need to move.

If the satellite is 5 or 6 degrees above the horizon for your location, you only need to be sure that you can see the horizon. The dish would need to be elevated hundreds of miles to add a degree. I don't have the formula handy, but elevating the dish even 10 or 20 miles would not add additional satellites.
 
my elevation is at 17.1 degrees I was trying to use setup on the back porch about 3 feet off the ground i will post pics to show you guys what i am talking about. i tried it the other day with no luck good weather to.

dan rose
 
How far off the ground do you have to be to pick up on 30w I am still having trouble trying to get that one satellite?

Dan Rose

You can take a 2' level and sight along it with the end elevated ~4". If you see sky in the direction of 30W you should be good to go. That'll give you an elevation of 9.5 degrees which is more than you need for Indiana.
 
my elevation is at 17.1 degrees I was trying to use setup on the back porch about 3 feet off the ground i will post pics to show you guys what i am talking about. i tried it the other day with no luck good weather to.

dan rose

For 17 degrees, use about 7" on the end of a 2' level.
 
...The dish would need to be elevated hundreds of miles to add a degree. I don't have the formula handy, but elevating the dish even 10 or 20 miles would not add additional satellites.
Thanks, I was looking for this kind of info a few months back. Even if I could convince someone to build some super Petronas Towers II in my backyard it would be to no avail to get an additional satellite. Too bad, because with a 20 mile high building I could charge good money for people to BASE jump from my dish farm.
 
Yea, but the max coax run anybody has ever talked about here, is 10 stories.
Can you imagine the loss at 20 miles?..? - ;)
 
If I remember right, you have to go UP 40k feet to add a satellite that's around 2° below your horizon. Thread: point dish angles that consider altitude
For an understanding of inverted offset dishes:
 

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Math contribution for the day...

The altitude you need to get LOS to a satellite that is at an elevation(?) below the horizon:

Radius of earth, R = 3965 mi = 20935200 ft (or use whatever number you feel is accurate for your location)

Altitude = (1/cos? - 1) x R

Distance to Horizon from the altitude:

Distance = R x Tan?

This is for perfect cases, like on the ocean or in the plains.

angle-alt-dist.jpg
 

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Slight aside.... When I was in the Navy on an aircraft carrier, we used 26 miles as a rule of thumb for distance to when the ships on the horizon would disappear. On radar, it was a little farther because you could actually pick up a ship over the horizon.. Be nice if we could bounce our satellite receiving off the ionosphere. But I'm moving into fantasyland.
 
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