Why so much Power?

[aaronread]

I think it was not CP (don't remember if it was H-pol or V-pol) and that was part of the problem they had. And IIRC, they generated their own power; 60 miles outside Dubai in 2003 was about 40 miles out into the middle-of-nowhere desert. I remember seeing a picture of the transmitter shelter and it was easily bigger than a football field. I'll bet a lot of that was to fit the generators and fuel storage!

I think you're right about the antenna bays, though...14 doesn't sound like enough to generate the kind of ERP they had. Maybe it was more like 20 or more? Here's the thing, I remember it was so many bays that the beam was compressed to a ridiculously narrow degree. So much so that aiming the array was not a trivial undertaking, and apparently the problem was that the array was off-aim just enough to put the beam shooting into the desert floor about 10 miles outside of town. We figured that out and suggested they have a local engineer re-aim the array and that's why I didn't get a free trip to Dubai out of it. Oh well. At least it spurred me to finally get a passport. ;D

Never did learn why the heck they elected to put the thing so far away from the population center. Especially considering the considerable atmospheric issues I'm sure they had every day from heat rising off the desert sand between the site and the city.

 

[w9wi]

I think it was not CP (don't remember if it was H-pol or V-pol) and that was part of the problem they had. And IIRC, they generated their own power; 60 miles outside Dubai in 2003 was about 40 miles out into the middle-of-nowhere desert. I remember seeing a picture of the transmitter shelter and it was easily bigger than a football field. I'll bet a lot of that was to fit the generators and fuel storage!

I think you're right about the antenna bays, though...14 doesn't sound like enough to generate the kind of ERP they had. Maybe it was more like 20 or more? Here's the thing, I remember it was so many bays that the beam was compressed to a ridiculously narrow degree. So much so that aiming the array was not a trivial undertaking, and apparently the problem was that the array was off-aim just enough to put the beam shooting into the desert floor about 10 miles outside of town. We figured that out and suggested they have a local engineer re-aim the array and that's why I didn't get a free trip to Dubai out of it. Oh well. At least it spurred me to finally get a passport. ;D

Never did learn why the heck they elected to put the thing so far away from the population center. Especially considering the considerable atmospheric issues I'm sure they had every day from heat rising off the desert sand between the site and the city.

Is it possible this antenna was highly directional in the horizontal plane? FCC regulations limit U.S. stations to 15dB of directivity, but it's technically possible to build something far more directional overseas where the regulations may permit it.

Is it possible they were trying to serve more than one country? Dubai isn't that big (geographically) and there are a couple of other fairly populated geographically small countries around there.

I once worked for a guy who'd served in the Navy in the Gulf. He indeed reported they have some pretty impressive tropospheric ducts around there. (and Bill Hepburn's tropo prediction site frequently confirms it)

 

[aaronread]

IIRC, it was omni...not directional. But like I've said, it's been a while. Pretty sure it was omni, though.

 

[davideduardo]

I always assumed that the reason that Grand Rapids on 93.7 dropped from 470KW when they added Vertical polarization was that a combination of transmitter and antenna to produce a total ERP of 940KW (470H and 470V) simply did not exist...and quite possibly still does not exist. With a 12 bay antenna, that would take roughly 75KW at the antenna, probably 80-90KW from the transmitter. I've never seen (or even heard of) an FM transmitter anywhere near that power rating.

The original WOOD-FM transmitter was supposedly a custom aural-only section from a VHF TV transmitter, adapted for bandwidth and other concerns... by RCA, IIRC. They of course did that because at the time there was no commercial FM transmitter big enough.

 

[Bob1370]

"Syracuse, Buffalo, and Utica have some fairly high terrain near their respective urbanized areas -- but from Rochester, the closest land exceeding 1000 feet AMSL is on the Ontario County line: http://www.cohp.org/ny/Monroe_1.html This may explain why Pinnacle Hill became the primary local antenna farm, not to mention that it casts a shadow on signals transmitted from the south. With Pinnacle so close to the market's center of population, there is less need for "superpower" than in a situation like WAMC's, WNED's, or WNTQ's."

One thing I wonder, though...back in 1952, when the revised rules for TV stations went into effect, Baker Hill (that high point on the Ontario/Monroe line) was still only about 10 air miles from downtown Rochester, quite a bit closer than the 17 mile trip signals have to take from Colden (Ch. 4 & 7) or South Wales (Ch. 2) to downtown Buffalo. Had someone decided to put an 800 foot tower on Baker Hill on either side of the county line back in 1952 it would have been an ideal site for the market's TV and FM signals and given them all full power at a full 1000 feet above average terrain--not to mention enough height to clear any natural or man-made obstacle in the way of full metro coverage. The area was nearly unpopulated so the likelihood of a NIMBY problem like the one that delayed the building of the Pinnacle Hill tower farm for a good 18 months in 1947-49 (and maybe delayed a second TV station in Rochester for five years) was nil. It also would have made the engineering of all the Rochester stations a bit easier since 13 on Pinnacle Hill is a hair's breadth from being short-spaced to Kitchener/Waterloo, while on Baker Hill there'd be plenty of margin for error.
The other Rochester TV stations would be properly spaced from either site. And FMs could have been built at much higher power, and fit within even current spacing requirements.