I know that when you drop in a new allocation, there has to be a place where it will work non-directionally. Does that apply to class upgrades? There's a station not too far from me that was a class A and upgraded to a B1, but not at full B1 facilities. I guess what I'm asking is : Can any class A that's not short-spaced or not on the threshold of being short-spaced apply to be a B1 at whatever power level will support contour protection? If they can, then why isn't this a common practice? Is there a specific FCC rule that addresses this?
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FM Class Upgrades : How Do They Work?
- Thread starter BobOnTheJob
- Start date
The upgrade is essentially a minor change procedure, (in that there is no longer a need for a separate petition to modify the table of allocations) but in order to qualify there must be a site that will meet all of the minimum separation requirements for the new class of the station.
This does not mean that the station cannot use a site that is short-spaced, either through the use of a directional antenna or by contour protection (operating at a slightly reduced power to bring in the interfering contour towards an existing station that would otherwise be short-spaced).
To answer your last question, the reason there are not that many upgrades from Class A to a B-1 (or C-3 for those in "C" territory) is simply because most Class A stations (especially 80-90 stations on what used to be channels reserved for "B" or "C" facilities) are rather tight fits. Indeed, some Class A stations are technically short-spaced because they were assigned as 3 kw stations, with shorter minimum mileage separations than are now required for the 6 kw stations. So finding a fully-spaced higher-class site is just not possible.
Look at 73.215 for the rule on contour protection.
This does not mean that the station cannot use a site that is short-spaced, either through the use of a directional antenna or by contour protection (operating at a slightly reduced power to bring in the interfering contour towards an existing station that would otherwise be short-spaced).
To answer your last question, the reason there are not that many upgrades from Class A to a B-1 (or C-3 for those in "C" territory) is simply because most Class A stations (especially 80-90 stations on what used to be channels reserved for "B" or "C" facilities) are rather tight fits. Indeed, some Class A stations are technically short-spaced because they were assigned as 3 kw stations, with shorter minimum mileage separations than are now required for the 6 kw stations. So finding a fully-spaced higher-class site is just not possible.
Look at 73.215 for the rule on contour protection.
So consuder this situation: A full Class B (Station 1) licensed to a community about 30 miles north of a major city delivers an OK signal to the major city's northern suburbs but not such a good signal to some parts of the major city and the signal gets worse as you go further south. Second adjacent to this station is another Class B (Station 2), located about 30 miles south of the center of the major city. Station 2 runs a full 50 kW ND but from an antenna enough below 492' AAT that, if the antenna were at 492' AAT, the power would have to be reduced to ~38 kW.TomT said:
About 12 miles northeast of the center of the downtown area of the major city is a tower used by a third Class B (Station 3). Like Station 1, Station 3 is a full B operating with full B facilities. It has many fewer problems south of the major city than does Station 1. I'm told that if Station 1 wanted to move to Station 3's tower, it would have to downgrade to a B1 even though it could operate with full B facilites from the Station 3 tower without creating any prohibited overlap with Station 2 because Station 2, though nominally a B does not have quite full B facilities.
Moreover, if it were allowed to operate with full B facilities from Station 3's tower, Station 1 would still deliver a principal city signal to its present CoL. So why isn't the move of Station 1 to Station 3's tower permisslble without a downgrade of Station 1? It seems as though station 1 should be allowed to make this move because it could do so without any station having to downgrade and without causing any prohibited overlap.
The allocation rules are based on class only in the commercial band.
So if there was a B operating with 50 kW at 250' HAAT (e.g. Station 2), they would receive the same protection as a B with 50kW at 500' HAAT. This station could move to a 500' tower at any time with very little resistance from the Commish.
Since the station operating with less than full B facilities could make that upgrade at anytime, station 1 must protect the theoretical maximum coverage of station 2.
Now, in some cases, the licensee of station 2 would tell the FCC that it would not be upgrading and/or would accept the interference (creating short-spacing), especially if the licensee of station 2 was the same as of station 1. However, memory says they are no longer creating short-spaced allocations.
So if there was a B operating with 50 kW at 250' HAAT (e.g. Station 2), they would receive the same protection as a B with 50kW at 500' HAAT. This station could move to a 500' tower at any time with very little resistance from the Commish.
Since the station operating with less than full B facilities could make that upgrade at anytime, station 1 must protect the theoretical maximum coverage of station 2.
Now, in some cases, the licensee of station 2 would tell the FCC that it would not be upgrading and/or would accept the interference (creating short-spacing), especially if the licensee of station 2 was the same as of station 1. However, memory says they are no longer creating short-spaced allocations.
There is an exception where both stations were on the air before the adoption of the allocation tables back in the 60's. Hence the short-spacing allowed for DC's WJFK. Relying on this exception is hazardous, and appears to require the application of several carefully placed envelopes filled with engraved pictures of dead presidents.
Otherwise, the contour protection is based on the contours of the protected station at full power for the class, at the site they are using. Not to their actual power and contours.
Otherwise, the contour protection is based on the contours of the protected station at full power for the class, at the site they are using. Not to their actual power and contours.
Well, in this case, Station 2 is running 50 kW at something like 450' AAT from an antenna mounted on one of the towers of an AM DA--and the towers are already half-wave. I doubt whether there is room at the site for another, taller tower--even if it were self-supporting, but I'm guessing about that. The site is well maintained and physically quite attractive. I think it is in a residential area. All this suggests to me that going higher is not an option for Station #2. Even more to the point is that Station #2 is WAY short-spaced to another legacy Class B to its southwest. Any attempt by Station #2 to increase AAT without installing a DA would run afoul of protections to that station long before they ran into Class minimum spacings to Station #1.TomT said:
Sounds like 99.1 and 99.5 to me...and 93.7 is station C.
If that be the case, I believe that 99.1 can increase to 150 meters, irrelevent of the New Haven 99.1, as both are grandfathered. They can't move an INCH closer though without running a DA.
There's also a class A drop in on 98.9 to consider now too.
By the way, the problem with station B isn't necesarily second adjacent-IFs are also likely involved-although things have gotten better now that the IF involved is classed as a B1 instead of a B.
If that be the case, I believe that 99.1 can increase to 150 meters, irrelevent of the New Haven 99.1, as both are grandfathered. They can't move an INCH closer though without running a DA.
There's also a class A drop in on 98.9 to consider now too.
By the way, the problem with station B isn't necesarily second adjacent-IFs are also likely involved-although things have gotten better now that the IF involved is classed as a B1 instead of a B.
My understanding is that the distance from Station 3's site (the "poposed" location of Station 1) to the non-comm B1 10.6-MHz below Station 1 in the heart of the major city's downtown, is a few miles greater than the allowed minimum B-to-B1 spacing.LA_Guy said:
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