Dish Height

[PJ02]

Is there an easy way to calculate the height at which the dish needs to be above the roofline so as to clear the apex? it's mainly the 28o E and 30oW thats going to be the problem i would guess.

I've looked into using gorbtrack but tbh i don't understand what its saying.

Any advice.

Thanks

PJ

[Dark Cloud]

A very rough guide, weather permitting, is to see where the Sun is around 10.30 - 11am and You're Whistling Dixie !!.

[Detlef]

Well. If you are in London it is about 24° above the horizontal and in Glasgow it is about 21° above the horizontal.

Make sure the lowest part of the dish has a clear view.

[bgsats]

Just as a rough guide, if you have an ostruction in front of the dish, measure or estimate the height of the obstruction relative to the bottom of the dish. Whatever that measurement may be, you need to be double that distance away - if not, raise the dish so that the relative height of the obstruction is less.

[PJ02]

Hmm might be a problem then.

Serves me right for buying a house with south facing front.

I found the swedish calculator somewhere which said the dish had to be 22o for 30W, and rising to 29.5o elevation for 1o west

So in theory if i calculate the height of the peak of the roof i can find the angle of the roof (which i'm guessing at 45o atm, it's quite steep.) I just need to do some maths and find the height i need to clear 22o elevation.

There is no chance for the bottom of the dish to see above the top of the roof though, just as well i have a 9ft pole.

PJ

[Captain Jack]

The sun is only useful as a guide twice a year, when it follows the Clarke Belt... I had the same problem with my installation. In the end I put the dish as far back in the garden as I could and stuck it on a 2m pole. Careful though, the poles flex a lot, so you'll need some reinforcements along its legth... or at the top like me!

http://img157.imagevenue.com/loc482/th_03271_DSCF0159_122_482lo.JPG (http://img157.imagevenue.com/img.php?image=03271_DSCF0159_122_ 482lo.JPG)http://img153.imagevenue.com/loc522/th_03367_DSCF0160_122_522lo.JPG (http://img153.imagevenue.com/img.php?image=03367_DSCF0160_122_ 522lo.JPG)http://img135.imagevenue.com/loc412/th_03493_DSCF0161_122_412lo.JPG (http://img135.imagevenue.com/img.php?image=03493_DSCF0161_122_ 412lo.JPG)http://img146.imagevenue.com/loc376/th_03580_DSCF0162_122_376lo.JPG (http://img146.imagevenue.com/img.php?image=03580_DSCF0162_122_ 376lo.JPG)

[PJ02]

Interesting,

Captain are you able to receive all the sats with the dish?

Approx how far back is the dish from the rear of the house?

I'm reckoning the internal structure of my roof is a 3 x 4 x 5m triangle with possibly less on the height. With 2ft t&k's it might have to go up 4ft on the eves to clear the top.

Going to have to get up the ladder with the dish to really find out, although if i can fit it in the back of the garden that would be ideal.

PJ

[Captain Jack]

Hi.. see https://www.satpimps.co.uk/showthread.php?t=56924 for my list of sats!

I recently moved and at my old house I had a south facing wall which was perfect for dish location. On average I reckon I get 1-2% lower signal than I did before but I believe that's largely due to having a cable run of 35 meters!

From the dish to the conservatory, it's around 3-3.5 meters but I haven't measured this as I was mainly interested in whether I could 'see' the satellites over the house.

You best bet to check whether you have clearance is to find the elevation angle of the satellite you wish to receive, get a spirit level meter, a school protractor and a ruler 30cm long. Say the elevation of the satellite is 28 degrees above the horizon... Find that mark on your protractor and attach a ruler from the middle of the protractor (0 degrees) and through the 28 degree mark.

Find the rough location of the satellite, stand where your dish would be and point the spirit level meter towards the satellite bottom side up, making sure that the meter is level horizontally. Place the protractor on top of the spirit level meter and you will find that the ruler will be pointing directly at the satellite. Look along the length of the ruler and see whether it's clearing the roofline of the house....

Hope the above makes sense... A picture can describe a 1000 words but I can't find such a picture..

Anyway, the above will give you a rough idea of your roof clearance... I hope!

[PJ02]

Back garden proved a no go, couldn't receive anything west, dam house.

Went for putting it on the roof, but i must have the hardest bricks to drill through. Got the first mount up and tried the pole. too small.

Need to find a larger (4m) pole for this.

Ahh well, i've jury rigged the sat for hotbird in the mean time though.

PJ

[Detlef]

A 4m pole will move about a lot in the wind, so could prove troublesome.

A scaffold pole will be stiffer but heavy. If you have a m8 with a welder try adding some anchorages to a steel pole and use lashing cable back to some firm points.
You can also get mast fixings that replace a roof tile and then run the pole through the roof to a joist - this means you can get the dish near the peak.

[Over in Belgium before the days of Sat, you used to see TV aerials that were about 4m above the houses with all sorts of lashings. Looked more like Rugby than private dwellings.]

[PJ02]

Ahh should have said, the majority of the pole will be below the eves as i didn't want to put the fixing too high up the wall as theres not a huge amount of bricks above. (i've got it in the 7th brick layer down from eves) the K bracket will be approx in the middle of the house.

BTW finding scaffolding is becoming hard.

PJ

[Captain Jack]

scaffolding should be easy to find. Try yellow pages for your local scaffolders. For a few quid you'll be able to get the poles and brackets