Distance from objects when installing dish?

[jerryt]

I am installing a Toroidal T90 on the south side of house.

Neighbor's house is a single story and about 10 feet south of the install sight.

There is a HOA, so I would like to mount the dish as low as possible.

Question, How do I determine the lowest install height of the dish, where the neighbor's roof won't interfer?

Thnaks

 

[vj9999]

Try this. You don't have to enter elevation angle, it will automatically give you the smallest elevation based on the distance and height of the obstacle. It will also draw you a nice graphic to help visualize. Measurments must be entered in metric.

http://www.satlex.de/en/elobst_calc.html

 

[jerryt]

it will automatically give you the smallest elevation based on the distance and height of the obstacle. [/URL]

Thanks, that was perfect.

Now, I can determine how high on the wall to mount the dish.

 

[jerryt]

Tried the scientific methold of clearing an obstruction.

Used the angle calculator, made my own sight gauge, checked compass headings. checked and rechecked everything.

Mounted dish 3 feet higher than my calculations called for, aligned dish and tried to receive channels;

Maybe 1 in 50 channels, very low signal.

This is a toroidal dish and only the center lnb is working 95%.

Best I can figure is my calculation are (were) way wrong.

But since I can tune all of the satellites with a signal meter, some part of the dish must be seeing over the obstruction??????????????

Best I can figure is the obstruction is SHADING (blocking) most of the dish with the result of very little signal strength on all the satellites. Instead of receiving the signals with all 90cm's of the dish, it must be like 20cm's or something.

Only thing I can think of to try next, is relocating the dish higher on the wall.

I figure another 38" higher. That is the height of the dish and I know some part of the dish is seeing over the obtsruction now.

Can an obstruction distort the signal?

Any suggestions?????????

 

[Tron]

Toroidals are very tricky to install. Are you sure your elevation and skew settings are correct for EACH LNBF? If the skew is off, the LNBFs away from the center will not get adequate signal.

I have not yet installed my T-90, since I am still searching for a NPRM for it and am on a tight budget the rest of this month.

 

[jerryt]

Toroidals are very tricky to install. Are you sure your elevation and skew settings are correct for EACH LNBF? If the skew is off, the LNBFs away from the center will not get adequate signal.

I have not yet installed my T-90, since I am still searching for a NPRM for it and am on a tight budget the rest of this month.

Dish was set up and working fine at another sight. I didn't disturb the setting, just moved down the street. Same Skew, Elevation and Azimuth. The new sight is very obstructed though??????????????? The signal meter is picking up the signal on the the most east and west satellites just fine. (can even tune some channels). So I believe this is not an issue with the dish aiming.

Setting up the T90 has been very straight forward for me; This is what I advised other T90 owners.

"http://www.satlex.de/en/wavefrontier_calc.html (Calculator is incorrect on one side)

Determine the 40 degree part of the arc you want to cover.

Determine your center satellite.

Align the dish with zero skew to the center satellite.

Pick one most west satellite and one most east satellite, both of which are strong and adjust the dish skew until you can receive both.

Readjust your center lnb, and start installing the remaining lnb's for that part of the arc.

Azimuth is not critical because the lnb mounts slide and make up for the azimuth being off a degree or two.

Elevation is a very critical, like 1/8 turns of the nut!!!

Skew is a compromise, ie you may be able to get a 10 signal strength on the most east and west satellite. but the best you can get on both is an 8 as a compromise. for example at skew of 50 degrees west satellite is a 10. at skew of 56 degrees east satellite is a 10. the compromise is both satellite received as an 8 with the skew at 53 degrees.

I have had great success with shimming the lnb's up slightly after tunning the whole dish. I place a wedge between the lnb and the holder. Gets back the higher signal lost during compromising on the skew. I have tried readjusting elevation (That what the wedges do) but can not get the improvement that the wedges give.

14 satellites on one dish, you gotta love that."

Thanks for any suggestions. Hope to try relocating the dish today.

 

[jerryt]

Relocated dish up another 26 inches, completely over the fence line. It is very hard to lift the dish that high. Very disappointed with this install sight. I didn't want the dish over the fence line.

Well, I got PBS-HD back, but it is still weaker than before I moved the dish. I believe I will need a crane to raise the dish any higher. The higher the dish the higher the wind loading. Plus I will have to take it down now when Hurricanes approach.

Maybe I'll just have to sell all my satellite stuff and buy cable.

 

[Tron]

Jerryt, thanks for the links and the helpful advice on the T-90 install!

It does sound like you might have a LOS issue there. Hurricanes are a potential problem here in New Orleans as well... I watched in June, as Cindy hit us directly, both of my dishes (the Winegard and the Channel Master) up on my shed roof. I was waiting for one of them to go flying across the yard. They stayed put, and I didn't even have to re-peak them after the hurricane blew over!

Of course, we're talking about a weak Category 1 with Cindy...

 

[jerryt]

noted something interesting today. The lnb for AMC 3 is pointed directly at one of the mounting screws on the subreflector. That can't help the signal. Appear to be able to consistantly get my other satellites. All the signal numbers are low though.

Anyone know how looking over a roof effects the satellite signals? I read something about heat reflecting from a roof being is seen as noise?

 

[Tron]

My install is located on the flat roof of a shed attached to my house. The house (with a pitched roof) is directly west and south of the shed part. So any satellite that is west of, say, 95W is over my house and therefore over the tapered roof.

My Channel Master 1 meter dish is pointed at an angle over the roof. It's fixed at 123w (G-10R), and I have no issues, other than the standard cross-pole interference everyone else is experiencing.

The roof does prevent me from seeing 148w, but its a moot point since the tall trees across the street from my house would prevent it anyway (148w is only 19 degrees off the horizon where I live)...

 

[jerryt]

Thanks Tron

Mounted my 36" motorized dish in place of the Toroidal, and I am able to get all the satellites. So the line of sight must be OK.

I can't get my new Skystar 2 card to move the motor though.

I guess I must have got something out of alignment on the Toroidal dish when I moved it.

 

[Tron]

Maybe the LNBFs need slight repositioning? From what I read, toroidals are tempermental. Gonna tackle my T-90 install soon...