line of sight

iwol

hi all just a quick question,im just making sure my conifers arent blocking any signal...on 7west for example at my lat/long the smw software says the signal comes in at 27 deg,but does this mean of the flat face of the dish ie a straight edge from top to bottom or 27 deg from the level floor,i know it doesnt make much dif at 7w,but when you go to 42e it might ,thanks in advance


i was just going to put a digital inclinometer level(600mm long) at the lowest point of the dish adjust the angle of the level then look down the level to check it clears the conifers

Robbo

Its 27 degrees from the ground I think, not that it makes any difference from higher up, its still 27 degrees, as the satellite is 22,000 miles away, a few metres makes no difference.( OK, it will be be about 1 millionth of a degree)

So, all you need to do is to measure the elevation angle from the bottom of the dish to the top of the tree, if its less than 27 degrees, you have line of sight, if it's more you don't. So yes, what you intended to do with the digital level is correct.

Tsiklon

Yes, 27 degrees is the angle from the ground to the satellite. So 0 degrees elevation means the satellite is sitting just on the horizon, and 90 degrees would have the satellite directly above e.g. if you were living on the equator.

You can find the elevation of a prime focus dish by laying a plank across the face of the dish and using a inclinometer. For an offset dish, it's more complicated. You need to first align it to a satellite of known elevation and then calculate the offset angle for any subsequent measurements.

Huevos

Don't laugh! I put a sighting tube on my dish as I could never figure out quite where it was pointing. Now all I have to do to know if I have line of sight to a satellite is look through the tube.

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