Would Sox games be on 93.7 HD signal?

Sid Schweiger sid@wrko.com
Fri Mar 12 11:07:39 EST 2010

"if it can tune in HD3 channels, which operate at no more than 10% of the station's full power..."

Not so.  You need to get your head out of analog when talking about HD.

HD carriers are transmitted at a fixed data rate, and on FM-HD that data rate is subdivided among however many audio channels the station wishes to transmit.  For example, in hybrid mode (meaning, transmitting analog along with the digital), the maximum data rate the iBiquity spec calls for is 150kBps.  That data rate can be subdivided into multiple channels but is a single stream of data at a constant power output (for the most part, FM HD carriers are run at 1% of the analog power level, equivalent to 20dB below analog carrier level, although some stations are now able to raise that to 4% [-14dBc] per a recent FCC ruling).  Typically the largest piece of that total data rate is reserved for the HD1, which is a simulcast of the analog audio, but it's really up to the station how they want to subdivide it.  Subject to change, Mike-FM (HD1) is using 48kbps, Funkytown (HD2) is using 48kbps and the WEEI simulcast on HD3 is using 24kbps.

If analog broadcast is ever turned off, sometime in the distant future, the iBiquity spec calls for a maximum data rate of 300kbps, which is enough to support several high-quality channels as well as surround sound.

Sid Schweiger
IT Manager, Entercom New England
20 Guest St / 3d Floor
Brighton MA  02135-2040

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