Possible obstruction?

[gpcramins]

Hello folks,
I am currently stationed in Guam (U.S. Navy) and after being fed up with the local cable service decided to plunk down the cash for 2 c band antennas to receive Asiasat 3S and Panamsat 8 (which will be switched to NSS 5 when I receive the Powervu receiver from the exchange for AFN reception). The install date is 01 Feb and I have been outside figuring elevation and azimuth settings for my location. My question is how much clearance should I have from my residence? The reason I ask is that I live in government housing, and although I have clearance to put the dishes on the roof (which would require a non penetrating mount and I would have to build it myself), I have some space in my yard which would be better for my application. If the received signal were in a perfect circle (the same diameter as my dish, 6 feet), it would clear my roof by 7 feet, do you guys think I would have reception problems? NSS 5 is at an altitude of 43.5 degrees (azimuth 106 true) at my location and about 10 degrees above my roof from where I would mount the dish. I know Panamsat 8 will work fine, as it is about 60 degrees in elevation so all the dish has to do is pretty much point up, and Asiasat 3s has no obstructions as it looks over my front yard at 42 degrees elevation, azimuth setting of 254 true. Also, as we get hammered by typhoons periodically, it would be easier for me to remove the dish in the yard as opposed to my roof. For those who advocate a larger dish, 6 feet works fine down here, and I am only about 810 nautical miles above the equator, well in the footprint, and you don't need a larger dish to receive these sats. One more question, the local dealer supplies a receiver labeled "Chietta", likely a Chinese clone of one of the more popular receivers. Although it seems to work well (demonstration), I will likely replace it with a Fortec Star or Coolsat 5000, any advice here? Thanks for any info, and by the way, after reading through these forums and sounding knowledgable when I entered the store, the price for installation dropped by a few hundred dollars...
Garry

 

[mkm4]

As long as nothing is between your dish and the satellite, you shouldn't have any problems. Being near something shouldn't be an issue unless its a radar antenna.

 

[iammike]

Sounds like some simple geometry should answer the question. I think all you'd need to do is multiply the distance from your dish to your house by the tangent of 43.5 degrees. The answer should give you the height your dish is able to clear and still get the signal. The tangent of 43.5 degrees is .949, so if your dish is 20 feet from the house it should be able to clear 19 feet. Actually, your dish will probably be a few feet off the ground so you would most likely be able to clear a little higher than 19.

I have a question, which will probably show my ignorance, but wouldn't it be simpler to just get a motor and one dish rather than getting two dishes. Then you could also get other satellites you have line of sight to.

 

[gpcramins]

Polar mount...

Thanks for the info, and I did work some trig, determining that the boresight for the dish centered on NSS 5 would clear my roof by 10 feet. The reason I am installing 2 dishes is that I cannot locate a polar mount for the dish. It is a Fortec Star 180cm and only comes with an AZ/EL mount. I would love to order an 8 foot dish with a polar mount, but the shipping to Guam is quite costly. For example, I was quoted approximately $900.00 to ship a 7.5 foot Sami dish out here, in addition to the price of the dish. Had I known about this one year ago when I shipped out, I would have bought the dish and had it sent with my household goods. What I will likely do when I have this whole thing setup is build a polar mount (I can weld) for one of the dishes and use that. Supposedly Sadoun maybe offering a polar mount for this dish in the near future. As soon as they do, my order will be in.

 

[iammike]

I was quoted approximately $900.00 to ship a 7.5 foot Sami dish out here, in addition to the price of the dish. Had I known about this one year ago when I shipped out, I would have bought the dish and had it sent with my household goods.

Wow! $900, that's around double the cost of the dish.