FM Class Zone I & I-A (Class B & B1)

[e-dawg]

When I look at the FCC maps for FM stations classes for Class B only stations. I know majority of Zone I in the U.S. includes all of Connecticut, the District of Columbia, Delaware, Illinois, Indiana, Massachusetts, Maryland, New Jersey, Ohio, Pennsylvania, Rhode Island, and West Virginia. It also includes the areas south of latitude 43.5°N in Michigan, New Hampshire, New York, and Vermont; as well as coastal Maine, southeastern Wisconsin, and northern and eastern Virginia. Also, Zone I-A which is south of 40 N in the state of California, Puerto Rico, and US Virgin Islands. How come the state of Kentucky is missed from being a Class B status, and why only parts of Virginia? Does it have to do with politics?

Also, why did the FCC created maximum of Class B only in these regions and not others?

 

[w9wi]

When I look at the FCC maps for FM stations classes for Class B only stations. I know majority of Zone I in the U.S. includes all of Connecticut, the District of Columbia, Delaware, Illinois, Indiana, Massachusetts, Maryland, New Jersey, Ohio, Pennsylvania, Rhode Island, and West Virginia. It also includes the areas south of latitude 43.5°N in Michigan, New Hampshire, New York, and Vermont; as well as coastal Maine, southeastern Wisconsin, and northern and eastern Virginia. Also, Zone I-A which is south of 40 N in the state of California, Puerto Rico, and US Virgin Islands. How come the state of Kentucky is missed from being a Class B status, and why only parts of Virginia? Does it have to do with politics?

I'll never find it again, but in the old issues of Broadcasting on David Eduardo's website there's an item about the moving of the line in Virginia. I don't recall it being politics in the Democrats-vs.-Republicans sense, but IIRC it was done at the behest of a station that wanted to upgrade & was prevented by the existing rules. Either the whole state was Class B & someone wanted to upgrade to C, or the whole state was C and the distance separation requirements prevented someone from doing what they wanted to do & they wanted the looser requirements of Class B territory.

I think the Ohio River made a fairly natural B/C boundary. Kentucky is, of course, a Southern state with cultural, business, and population distributions different from those across the river in Indiana. Those differences were considerably greater when the boundaries were laid out 50 years ago.

Ironically, while the state of Kentucky is in Class C territory, four of Louisville's eight FM stations are across the river in Class B territory in Indiana. (and two more are Class A stations. There's only one Class C station in Louisville & due to a low antenna, it was reclassified as C1.)

Also, why did the FCC created maximum of Class B only in these regions and not others?

In the initial FM rules there were only two classes of FM station: A and B. However, the FCC announced that, outside the "northeast", they would accept requests to waive the 20kw/500' limit. (that means that for quite some time, there was no maximum power limit for FM stations!) (well, you did have to show it wouldn't interfere with anything else & that someone would sell you a transmitter powerful enough to build it!)

The idea was that in the Northeast, cities large enough to support a Class B station were close enough together that reliable FM service could be provided pretty much everywhere in the region within the normal Class B power limits. And by limiting power, *more* Class B stations would be possible providing more variety in programming.

Outside the Northeast, cities large enough to support a Class B station might be far enough apart to leave gaps in coverage, "white areas" with no FM service. Allowing higher powers would of course increase coverage & the chances these "white areas" would not exist -- the chances that *everyone* would be within the service area of at least one FM station.

 

[PTBoardOp94]

The shape of the maps has a lot to do with where stations were in the early 60s when they were drawn. The commission's staff looked at the table of allocations and decided that certain states were already "full" or close to it under the rules at the time.

There are places in zone I that arguably belong in zone II. Southern Illinois (south of I-70), most of West Virginia, central PA, and possibly southern Ohio, but in reality the system as it is drawn works OK, and it isn't hard to tell someone to draw a line from St. Louis to Newport News and tell them that points northward are class B land.

 

[Kmagrill]

Another way to see the situation is that the FCC needed population centers to have their own service more than receive service from other cities. In the denser areas, cities are much closer together. Allowing class C stations would have prevented allocations in other nearby cities.

In other regions, cities are often separated by hundreds of miles, so more powerful signals could be added to the population centers without disrupting service in adjacent cities. Since much of the country was rural, no service was considered commercially viable, so the bigger signals from the cities served a larger area that wouldn't have been served otherwise.

As the character of the country changes, it might, eventually, be argued that the limits should be changed, but that would likely just result in class C being taken off the table for most areas that have grown a lot.

 

[joebtsflk1]

With Class B almost equivalent to the C1 in mileage separations, I'd argue that the C1 with the 60 dBu protected service area would have better building penetration than the B. What would happen if Bs could move to C1 power levels and move from 54 dBu protected contours to 60 dBu?

 

[BobOnTheJob]

With Class B almost equivalent to the C1 in mileage separations, I'd argue that the C1 with the 60 dBu protected service area would have better building penetration than the B. What would happen if Bs could move to C1 power levels and move from 54 dBu protected contours to 60 dBu?

Class B's 54dbu protection is the only semblance of common sense we have left. When 60 is the limit as it is with Class A's, there's often a cat fight halfway between...something that's nicely lacking when a pair of B's are 150 miles apart

 

[WNTIRadio]

Of course, Bob, come to the northeast where there are two B's 80 miles apart beating on each other!! It's fun to drive through central Jersey and hear 101.1 and 100.3 change every few feet you move.

 

[semoochie]

Class B isn't almost equivalent to C1. It's C2. C1 is 100KW @ 299 meters. B is the same power/height level as C2 but B protects to 54dbu and C2 to 60dbu.

 

[Kmagrill]

Class B isn't almost equivalent to C1. It's C2. C1 is 100KW @ 299 meters. B is the same power/height level as C2 but B protects to 54dbu and C2 to 60dbu.

I believe that the point was that mileage separations in 73.207 are similar between class B and class C1 stations. This is because the B protects to the 54dBu while the C1 is to the 60dBu.

The suggestion being advanced is that Bs be allowed to upgrade to C1 which would give them better building penetration in light of today's noisier RF environment and denser buildings. Although it might help a little, the actual power increase is only 3dB which is almost nothing. Existing Bs would also need taller towers to really take advantage of the scenario. However, in places like New York City where the majority of antennas are already very high, the gain would be an immediate 8-10dB increase in RF which is noticeable.

 

[Schroedingers Cat]

Class B isn't almost equivalent to C1. It's C2. C1 is 100KW @ 299 meters. B is the same power/height level as C2 but B protects to 54dbu and C2 to 60dbu.

I believe that the point was that mileage separations in 73.207 are similar between class B and class C1 stations. This is because the B protects to the 54dBu while the C1 is to the 60dBu.

The suggestion being advanced is that Bs be allowed to upgrade to C1 which would give them better building penetration in light of today's noisier RF environment and denser buildings. Although it might help a little, the actual power increase is only 3dB which is almost nothing. Existing Bs would also need taller towers to really take advantage of the scenario. However, in places like New York City where the majority of antennas are already very high, the gain would be an immediate 8-10dB increase in RF which is noticeable.

Canada pretty much upgraded all of their Class Bs near the border to Class C1 for that very reason. But under treaty, they are protected to the 54 dBu from US stations, whereas full Class Cs are protected to the 58 dBu. The biggest problems in upgrading the Class Bs to Class C1 in the US would be the cochannel Class As, all being relatively new, and mostly full 6 kW allotments. First adjacent Class As to Class Bs were already a problem, as the distance separation requirements didn't fully protect them, even at 3 kW.

Frankly, the rules were changed so often and so fast back in the 1980s and 1990s, that it would only make sense to go back to a contour based allotment system like NCE-FM still is, and 60 dBu protection for all classes, and have some of the interference flexibility allowed in Canada. And get rid of the silly First Local Service rules that are so capriciously applied. First Local Service never worked anyway. They almost all got bought out by big companies, and those companies played chess with them to put them back in the bigger cities anyway, contour wise. And the ones that didn't move to more populated areas mostly struggle economically due to the policy. Many COLs are absolute jokes, and many better COLs are precluded by a multitude of other rules.