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With the exception of the Mobile section, all of the pages here conform to a format. All kinds of data, if known, is provided. Much of it comes from the public databases of the FCC. Format information comes from reader contributions and my own personal loggings. 

This information and style is no longer current, but here for informational purposes.



What it all means for FM:
 
Birmingham WJSR + 91.1 100 356-D AC, RDS: WJSR-FM, mono
The city of license. This may not be the city the station primarily serves. The call sign of the station. If a web site is available, it will be linked, as shown here. If available, will take you to a map of the station's protected contour provided by the FCC. The area within the contour is the estimated primary coverage area. The frequency of the station. The power in ERP, which stands for Effective Radiated Power, in watts. The number is the antenna's HAAT, or Height Above Average Terrain. For FM, the stations are listed in feet. The format, if known. If the station broadcasts in mono, it will be noted here. If the station has an RDS, or Radio Data Service, signal, it is also noted here, including what the default message is.


What it all means for AM:
 
Troy WTBF 970  5,000/C  500 Talk/News *stereo*
The city of license. This may not be the city the station primarily serves. The call sign of the station. If a web site is available, it will be linked, as shown here. The frequency of the station. The power in ERP, which stands for Effective Radiated Power, in watts. The first number is daytime power, the second is nighttime power. Please note, as shown above, if a C is present before the second number, it signifies "Critical Hours" power. The format of the station, if known, is listed here. If the station broadcasts in Motorola C-QUAM AM stereo, it will be noted here.


What it all means for TV:
 
6 WBRC Birmingham 100,000 1042.0 Fox ST SAP
The channel the station broadcasts on. The call sign of the station. If a station web site is available, it will be linked, as shown here. The city of license. This may not be the city the station primarily serves. The power in ERP, which stands for Effective Radiated Power, in watts. The number is the antenna's HAAT, or Height Above Average Terrain. For TV, the stations are listed in feet. Network affiliation, if known. If there is no affiliation, then "Ind" for independent is listed. If a network has a web site, it will be linked, as shown here. If the station is known to broadcast in stereo, "ST" will be listed. If the station provides a second audio program, or "SAP", that will be shown as well.

More explanations:

Frequency / Channel
In the US, stations are assigned to frequencies by the FCC. The stations are separated by 200 kHz, and end with an odd number. Our FM broadcast band extends from 87.9 to 107.9 MHz. 87.9 is not assigned, except to a few experimental stations. Is isn't assigned because of the proximity to TV channel 6's audio carrier, which falls at 87.75 MHz, and can be received on many FM radios. Other parts of the world have different FM bands. In Japan, for example, the FM band ranges from 76-92 MHz. Some countries also space their stations differently. In Hungary you might find a station on 86.2 MHz! For AM, stations are assigned by the FCC and are all 10 kHz apart. Our AM band runs from 540 to 1700 kHz. Some countries, including Canada, assign stations to 530 kHz. In the rest of the world, AM stations are spaced 9 kHz apart.
Call Sign
The call sign of a station is assigned by the FCC. Like frequencies, a station can request a specific call sign, if it is available. Generally,  stations west of the Mississippi River begin with K- call signs, and stations east of the River begin with W- call signs. Some very old stations, like KYW in Philadelphia, were allowed to keep their old calls after the east/west standardization began.
City of License
The city of license is determined by the station when it submits an application. A city nearby the transmitter is picked usually. Of course, as with WOWC-FM, licensed to Jasper, a station may serve another market, in this case Birmingham. A station must pick a city within it's protected contour as it's city of license. I don't know why.
Power
FM stations in the US are limited to a maximum of 100,000 watts. AM stations are limited to 50,000 watts. Television is a little more complex. Channels 2-6 are limited to 100,000 watts, 7-13 are limited to 316,000 watts, and 14-69 are limited to 5,000,000 watts! Stations with unusually high antennas are often restricted to lesser power levels. FM translators are limited to 250 watts. I am not sure what the limit is on TV translators. A few FM stations are granted "grandfather status", which means they are allowed to operate at higher power levels than current FCC standards allow. WBCT in Grand Rapids, MI has 300,000 grandfathered watts! Even with only an antenna at 500 or so foot HAAT, they still have quite a coverage area.
HAAT
Height Above Average terrain differs from height AMSL, or above sea level. HAAT more accurately reflects the overall "height advantage" an antenna has over surrounding terrain.  So while an antenna may be 1,500 feet up on a tower, it could still have a HAAT of perhaps only 600 feet, if the surrounding terrain is very hilly and the tower is in a valley.
Format / Network
There are countless ways to identify a station. You might hear a "soft rock" station or a "lite hits" station. They probably sound the same! I've tried to standardize the format names a little. Click here for information regarding radio station formats. In addition to the "Big 4" television networks (ABC, CBS, NBC and Fox), there are number of smaller networks. Some have general audience programming, like UPN, The WB and PaxNet. Others, like America One, The Box and Trinity Broadcast Network cater to a specific group or taste. Then there's public television.
RDS
Radio Data Service is a data stream within the FM carrier. It has the capability to transmit all kinds of information, like station call sign, song names and even radio coupons. Check out the RDS Forum for more information.
AM Stereo
Some (not enough in my opinion) AM stations broadcast in stereo. They use the Motorola C-QUAM system, which was recently adopted as the official AM stereo method by the FCC, after years of letting us languish with a bunch of non compatible standards. AM stereo actually sounds quite good! Many late model car stereos can decode AM stereo. Only one (now discontinued) portable radio was recently for sale, the Sony SRF-42 Walkman. It was kind of cheap, but was AMAX certified, meaning it met certain requirements or decent sound. If you look, you might find one at a local Radio Shack for only US$30. AM stereo is much more popular in some Asian countries like Japan. It is also quite popular in Australia.
TV SAP / Stereo
Television stations can broadcast a stereo signal using a method called MTS (Multi-Channel Stereo) sound. A second channel of audio can be carried as well. SAP (Second Audio Program) is the name of this second channel. It is monaural and relatively lo-fi. Our local public television stations use a SAP channel to carry descriptive video service audio (DVS usually fills any quiet parts of a program's audio with a voice describing the scene or motions of actors on screen) and audio for The Alabama Radio Reading Service for the Blind. Some stations, like WBRC in Birmingham carry weather reports. In other parts of the country, where a second language is widely spoken, the SAP is used for dubbed audio. WBRC recently aired an episode of Cops where the SAP was used for Spanish language dubs. Many cable companies provide SAP channels for networks like HBO, Cinemax and Cartoon Network, who provide extensive Spanish language programming.

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