Will free over-the-air broadcast television in the United States soon become a thing of the past? That prospect would have seemed impossible to me not too long ago, but I wonder if it is what the future holds.

Back in November 2009, the Consumer Electronics Association and CTIA (a wireless communications trade group) wrote a letter to the FCC requesting ways to “reduce the amount of spectrum assigned to broadcast television licensees.” You can see a copy of that letter here. Their key point comes at the end of the letter:

Without swift Commission action to identify and clear significant portions of electromagnetic spectrum below 3 GHz, consumers and businesses in this country will be unable to access the Internet and information sources so necessary to be competitive internationally.

The implication here seems obvious: why reserve large sections of broadcast spectrum for television when “fewer than ten percent of American households rely on over-the-air transmission to view broadcast content”?

There is enormous pressure at the moment to free up more bandwidth for wireless communications. Many long-time users of frequencies are thought to be at risk for relocation or removal. For example, it seems likely that amateur radio will lose rights to many frequencies, especially in the microwave range. But television is an especially rich target for the wireless companies because its frequencies are adjacent to the ones they use today.

VHF channels 1 to 13 were the first reserved for television back in the 1930’s. Channel 1 (which suffered from interference problems) was removed when broadcasting began in earnest following World War II. UHF channels were added in 1952, comprising channels 14 to 83.

Channels 70 to 83, which were mostly used for repeaters, were removed in 1983. More recently, channels 52 to 69 were removed as part of the digital broadcast conversion in 2009. So the television channels available today in the United States total 49: VHF channels 2 to 13 and UHF channels 14 to 51 (excluding channel 37 which is reserved for radio astronomy).

The situation is complicated by the fact that the VHF channels are not working out well for digital television. Many of the remaining digital VHF stations have requesting relocation to UHF channels. That means that the only widely usable channels for digital television are the 37 UHF channels.

In a separate proposal, the Consumer Electronics Association and CTIA have suggested replacing high-power television transmitters with networks of lower power transmitters. This approach, known as distributed transmission system or DTS, could reduce the number of channels required to cover an area. DTS isn’t a new idea and is considered one potential way to replace coverage lost in the digital television conversion. It would also have the advantage of working with existing televisions.

But their proposal estimates that between 100 to 180 MHz of bandwidth could be freed up. That would be the equivalent of 17 to 30 UHF channels. If thirty channels were removed from the UHF band (assuming that channel 37 remains unused), that would leave only seven UHF channels available for digital television. It’s hard to see how that could help but destroy over-the-air television.

A skeptical observer might wonder if the real issue is preventing competition with future wireless video services. For example, one of the uses of the recently vacated channels 52 to 69 is MediaFLO, a service created by Qualcomm. MediaFLO uses channel 55 to broadcast television to mobile devices.