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Furthest FM station in Philadelphia
- Thread starter phils07
- Start date
If I understand how FM works and how the FCC has set it up, the most powerful FM's in a market will go out in a circular pattern for about 60-70 miles before running into another FM on that same frequency. This was recently discussed, I believe on the Philly board, where we were discussing WDAC 94.5 Lancaster and WPST 94.5 Trenton. Both get out approx 60-70 miles, but WDAC due to its high tower gets that distance using far less power than WPST as their tower is lower to the ground, etc. Someone explained that FM's in NYC have their signal coming from the Empire State Bldg and due to that height they too save on their electric bill, yet are only allowed to get out as their primary signal the same 60-70 miles.
There are others here far more qualified to answer this, but that's my understanding of that issue based on the discussions previously held here. If I've not given you the correct info, I'm sure some of the others who actually have worked with or repaired transmitters and know something about the electronic end of a radio station, will chime in to clarify the answer to help my lack of knowledge. Hope that is helpful a little bit.
There are others here far more qualified to answer this, but that's my understanding of that issue based on the discussions previously held here. If I've not given you the correct info, I'm sure some of the others who actually have worked with or repaired transmitters and know something about the electronic end of a radio station, will chime in to clarify the answer to help my lack of knowledge. Hope that is helpful a little bit.
Your explanation is basically correct, Mike, with a few clarifications:
In most of the northeastern US and California, the most powerful FM signals allowed are called "class B" - 50,000 watts from an antenna no more than 492 feet above average terrain, with power adjusted downward from there as height goes up. In the rest of the country, where markets aren't spaced as tightly, "class C" stations are allowed - 100,000 watts at as much as 2000 feet above average terrain.
All other factors being equal, any class B station with maximum facilities will go out as far as any other class B station. For class B stations, the FCC says it's 65.1 km from the transmitter site to the "protected contour." It's certainly very possible to hear a station beyond that radius, but its reception is not protected from interference from other stations beyond that distance.
In the real world, of course, all factors are NOT equal. Terrain can affect the reach of an FM signal, as can factors such as multipath (signals reflecting off buildings, land and water) and even the choice of transmitting antenna model and the placement of the antenna on the tower.
And then there's interference from co-channel and adjacent-channel stations. In the crowded northeast, just about every FM signal is short-spaced to every other FM signal, especially since so many of them were in place before the current FM spacing rules were established in 1964. So WBEB, for instance, can't be heard as clearly to the north and east for as far as WOGL, since WBEB has to contend with co-channel interference from WCBS-FM on 101.1. (Same deal with WPST/WDAC on 94.5, WYSP/WQKX on 94.1, and plenty of other station pairs.)
Some FM stations that predate the 1964 spacing rules are allowed to continue operating at higher power levels than a normal class B station, but they are not protected from interference beyond normal class B spacing. I don't believe there are any such "grandfathered superpower FMs" in Philadelphia.
So which Philadelphia FM gets out best? It depends on direction, of course - but all of the Roxborough class Bs (94.1, 95.7, 96.5, 98.1, 98.9, 101.1, 102.1, 104.5, 105.3) are roughly comparable in transmitting facilities, with the big limitations on their reach coming from co- and adjacent-channel stations nearby. In practice, WOGL seems to me to have the clearest channel; you've got to go up to Binghamton or out to Altoona to hit the next stations on 98.1.
In most of the northeastern US and California, the most powerful FM signals allowed are called "class B" - 50,000 watts from an antenna no more than 492 feet above average terrain, with power adjusted downward from there as height goes up. In the rest of the country, where markets aren't spaced as tightly, "class C" stations are allowed - 100,000 watts at as much as 2000 feet above average terrain.
All other factors being equal, any class B station with maximum facilities will go out as far as any other class B station. For class B stations, the FCC says it's 65.1 km from the transmitter site to the "protected contour." It's certainly very possible to hear a station beyond that radius, but its reception is not protected from interference from other stations beyond that distance.
In the real world, of course, all factors are NOT equal. Terrain can affect the reach of an FM signal, as can factors such as multipath (signals reflecting off buildings, land and water) and even the choice of transmitting antenna model and the placement of the antenna on the tower.
And then there's interference from co-channel and adjacent-channel stations. In the crowded northeast, just about every FM signal is short-spaced to every other FM signal, especially since so many of them were in place before the current FM spacing rules were established in 1964. So WBEB, for instance, can't be heard as clearly to the north and east for as far as WOGL, since WBEB has to contend with co-channel interference from WCBS-FM on 101.1. (Same deal with WPST/WDAC on 94.5, WYSP/WQKX on 94.1, and plenty of other station pairs.)
Some FM stations that predate the 1964 spacing rules are allowed to continue operating at higher power levels than a normal class B station, but they are not protected from interference beyond normal class B spacing. I don't believe there are any such "grandfathered superpower FMs" in Philadelphia.
So which Philadelphia FM gets out best? It depends on direction, of course - but all of the Roxborough class Bs (94.1, 95.7, 96.5, 98.1, 98.9, 101.1, 102.1, 104.5, 105.3) are roughly comparable in transmitting facilities, with the big limitations on their reach coming from co- and adjacent-channel stations nearby. In practice, WOGL seems to me to have the clearest channel; you've got to go up to Binghamton or out to Altoona to hit the next stations on 98.1.
G
gunsmoke
Guest
In my observations, I think MMR gets out the furthest, I know going East/Southeast/Northeast they are the clear winner.
Thanks Scott for the added info and clarification.
gunsmoke said:
As well they should be. Their transmitter site at One Liberty in downtown Philadelphia is several miles southeast of Roxborough, where most of the rest of the big FMs are located. Likewise, we can expect 106.1 to do a little better to the north, since its site is in Wyndmoor, north of Roxborough.
(I haven't even gotten into the issue of directional FM antennas; WPEN-FM 97.5 is also at Wyndmoor, but it uses a directional antenna to work around its short-spacings with 97.3 in Harrisburg and 97.3 in south Jersey, so it won't carry as far as 106.1 in those directions.)
MMR used to get into most of Harford and Baltimore counties,as well as Baltimore City, while WYSP was spotty in those counties and absent in Baltimore itself. Now it seems to be reversed. I know one city/markets stations aren't necessarily supposed to reach anothers but with the frequencies 'staggered' as they are it was possible and in my case enjoyable since I like fewer Baltimore stations than Philly stations.
J
johnsummers
Guest
Scott is the man!! ;D
There are some grandfathered class B FM stations, but Philadelphia has none. The closest one I believe to us is in Williamsport, where WKSB has 53,000 watts at 1270 feet above average terrain-a normal class B would have about 6 kilowatts at that height. Pittsburgh also has quite a few grandfathered class Bs, as does Buffalo.
As you would head north, 'YSP would go first because of 94.3 WJLK. If you had a manually tuned radio, you could pick 'MMR up north of the Raritan River.phils07 said:
The first generation of digital radios were not very selective, so the signals were considerably shorter as a result of the splash from adjacents.
...sounds familiar.
Jeff in Sa-ra-so-ta!
I have found that FM stations that are 50kw at 500 ft above average terrain are stronger than the taller antenna stations with lower wattage. This is especially true when there are temperature inversions in the troposphere (when there is fog or a ring around the moon) that extend vhf and uhf radio signals. I always noted that Baltimore and DC stations came in stronger than NYC to the Philly area....one reason is NYC has the low wattage tall antenna stations.
Before all of the short spaced, drop-ins, the Empire signals mostly used the Alford antenna array that circled the top and bottom of the 102nd floor observation deck windows. the stations using it were all 5400w@1220'. (I think WBLS was lower power). AFAIK Alford is not used for primary anymore but those signals always had a penetration problem, but were able to jump hills (because of the "effective" 2 bay configuration) and have a decent range. I remember catching some in Atlantic City. That is no longer possible.stevations said:
The summer at the Jersey shore has always been fraught with Philly battling Long Island/CT because of co-channel.
Worse during the tropo.
I lost WCBS-FM at the top of the Raritan River Bridge regularly in favor of B101. I could see Empire from there.
Jeff in Sa-ra-so-ta!
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