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horizontal only FM stations

S

secondchoice

Back in the day (per 1980) when a lot of FM stations were financially a drain on AM FM combos, there were FM stations horizontal polarized only with more than 6 bays on the antennas for lower electric bills and smaller transmitters. IIRC before the commission started filling the FM band with more allocations, there was a time when existing FM stations could "upgrade" if there wasn't interference*. My question is how many FM stations didn't or could not improve their signal and still are horizontal only.

*example class A FMs could go 6 KW from 3KW
 
secondchoice said:
Back in the day (per 1980) when a lot of FM stations were financially a drain on AM FM combos, there were FM stations horizontal polarized only with more than 6 bays on the antennas for lower electric bills and smaller transmitters. IIRC before the commission started filling the FM band with more allocations, there was a time when existing FM stations could "upgrade" if there wasn't interference*. My question is how many FM stations didn't or could not improve their signal and still are horizontal only.

*example class A FMs could go 6 KW from 3KW
Click to expand...


secondchance- that is not quite correct. I suggest researching it. Or, if you are asking as or on behalf of a licensee, hire a qualified engineer to provide information and advise as needed.
 
Keep in mind that 1970's cars had vertical whip antennas. So, most FM's added vertical polarization way back then. The FCC allowed me to upgrade my Class A stations to 6 KW in early 1989. It's been a bad idea to be just vertical or horizontal for many decades.

He didn't need to pay me because I give it away for free. There are many bad and unethical consultants who will give you bad advice just so THEY can make a buck.
 
The original reason for horizontal only as I remember was because the horizontal plane was less noisy. Early fm receivers were all tube so noise was an issue hence horizontal polarization and the pre emphasis curve. As listening to fm in cars increased vertical was allowed. I don't know of any stations still just horizontal but I do know a few that are vertical only . They are primarily at the low end of the FM band and were designed to prevent interference with nearby TV channels which were only horizontal. If the FCC had allowed them to be vertical only near 88.1 and then they moved up the dial the commission also allowed them to continue vertical only. Of course FM translators can be one or the other or both.
 
Some stations run H-only because they're at a remote, generator-only site. It's a way to reduce the gas bill. US NCE's are allowed to run V-Only but not commercial licenses.
 
Greg Strickland said:
secondchance- that is not quite correct. I suggest researching it. Or, if you are asking as or on behalf of a licensee, hire a qualified engineer to provide information and advise as needed.
Click to expand...

I guess this should have been on a history page.


The reason this is on the engineering page is most likely some of the folks who still engineer could be dealing with class B or Cs that are still using old antennas.

The last class A that I know was using horizontal antenna was in the mid 1990s. They got a new tower and site to allow 100.1 in the Lexington KY market upgrade . Ended up with a nice ERI rotor tiller arm antenna, after I convinced the owner to not to try to reuse the old 4 bay horizontal antenna.

BTW Greg : I don't get how asking about antiquated FM antennas would be asking for a station owner. There was a period (late 1970's or early 1980's) when a lot of FM stations especially classAs upgraded before the commission try to put an FM allocation in any Zip code for a new COL they could squeeze them one in.
 
You pay more for ERI. But they are the best. I once saved and bought a 4 bay SWR. Boy did I ever learn a lesson the hard way. Get what you pay for. Replaced them with ERI. I've been happy ever since.
 
I have not seen a horizontal only antenna at any power level or station class in at least 40+ years. I'm sure there are examples out there, but they are uncommon, if not downright rare. Since the early 1970s, the majority of broadcast antennas for all classes of station are circular or dual H/V. The FCC only counts the power in the horizontal plane, so any vertical componant is free power, in a way. The vertical power cannot exceed the horizontal plane power. The reason that horizontal was originally used was that the FCC envisioned FM stations being just like TV, where everyone either had an outside FM antenna, or shared their TV antenna with thir FM receiver. Almost all external TV and FM antennas were, and still are, horizontal only. It was only in the 1970s that vertical polarization became important as FM started appearing in more cars.

Over the years, a number of petitions to the FCC have requested that the FCC allow for vertical only polarization, however, the FCC has consistently refused this request. The only valid exception that I know of is a few stations in the non-commercial part of the band that had to protect TV-6 signals by cross polarizing. As far as I know, no commercial station, except FM translators and boosters, are permitted to operate with vertical only antennas.

Lastly, to reinforce what Greg said, it is not correct that horizontal polarization played any factor in the FCC allowing class A stations to upgrade from 3kW to 6kW. The FCC has always only considered the horizontal componant of the FM signal in its calculations. The class A upgrade was permitted for any station that met the new minimum distance specifications, regardless of the antenna type. Stations that did not meet the minimum distance specs were still allowed to upgrade as long as there was a written agreement between that station and all affected stations to allow it. In most cases, it was class A stations that were short spaced to co-channel class A stations so both would agree to mutual upgrades. Keep in mind that prior to docket 80-90 where the class C3 and B1 classes were introduced, specific channels had been reserved for Class A stations only, so it was common to find long daisy-chains of affected class A stations that were all too close to each other to automatically upgrade.
 
ERI has always made good antennas. The quality has gone up on other brands over the years, too. I've used SWR occasionally without incident. PSI and a few others, too have been OK.
 
Kmagrill said:
ERI has always made good antennas. The quality has gone up on other brands over the years, too. I've used SWR occasionally without incident. PSI and a few others, too have been OK.
Click to expand...
I actually set in on a presentation with a guy that was a "contractor" for ERI. His big sales "point" for our non technical owner was the signal traveled in a "screw" pattern that penetrated buildings better with less signal reflected from large flat buildings.

I kind of laughed to myself. The main part of the market only had one building with 5 floors. Everything else was less than 3 floors.
 
I guess that "screw" pattern helped it burrow into the walls of the building better. LOL...
It's a helical output, but lots of other antennas produce similar outputs including the penetrator style, originally popularized by Jampro. I've always observed that the ring stub antennas "seem" to cover better than any of the other types. However, they are relatively narrow banded, which can cause issues in some environments. A lot of this is just what you prefer. They all radiate, except when broken.
 
Kmagrill said:
I guess that "screw" pattern helped it burrow into the walls of the building better. LOL...
It's a helical output, but lots of other antennas produce similar outputs including the penetrator style, originally popularized by Jampro. I've always observed that the ring stub antennas "seem" to cover better than any of the other types. However, they are relatively narrow banded, which can cause issues in some environments. A lot of this is just what you prefer. They all radiate, except when broken.
Click to expand...
The funny part, the pitch worked.
 
If you look up KZTI, KUEZ, KWNZ, and a few others you'll see they all broadcast from a very tall tower about 55 miles Northeast of Reno. Those signals exist strictly to serve the Reno market, and by putting a city-grade signal over Reno they have the ability to license an on-channel booster, which they all have. These stations are 100KW and they're horizontal-only, allowing them to run a mere 13.5 KW transmitter power into a 14-bay antenna. Ironically, the goal here is to put a weak signal into the market, giving less mutual interference to the booster. I think the same situation exists in Las Vegas, where some transmitters have to be far out of town to meet FCC minimum mileage separations.

Dave B.
 
We call those "Humpy Peak Boosters," after the remote mountain 60 miles east of Salt Lake City where this technique was pioneered.

It works best in mountainous areas (so you can use terrain to keep the "main" signal from reaching the target market and interfering with the booster. And it works best in places like SLC where the main local FM site is off to one end of the market.
 
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