The FCC has released the first set of rules for DTV channel sharing. As you may remember, this concept is similar to that of DTV subchannels. Indeed, from a technical standpoint, it's identical to the concept of subchannels – the only difference is that the two (or more) subchannels are licensed to and operated by different owners.
Channel sharing is voluntary.
No station will be required to split its channel. Stations must decide who they want to share with, the FCC will not assign sharing partners.
At this time, only stations participating in the incentive auction will be eligible for channel sharing. An incentive auction has been proposed that will allow stations to sell their spectrum for wireless use.
In the initial plan, if someone buys a station's spectrum, that station goes off the air. With channel sharing, that station can "move in" with another station that agreed to auction spectrum as well. Each station gets half the auction proceeds – and gets to stay in business.
Each sharing station is licensed separately.
Each station will hold a separate license and callsign. Each station is independently responsible for compliance with FCC programming regulations.
For example, assume WXXX and WYYY share a channel. WYYY decides not to keep a public file. WYYY will be sanctioned with a large fine – WXXX will not be sanctioned.
Each sharing station is entitled to the same must-carry rights on cable & satellite as they'd have if they had their own transmitter.
I have a couple of questions the FCC release doesn't answer...
What happens if there are technical violations involving the shared transmitter?
If one of the partners in a sharing arrangement loses its license (or voluntarily goes out of business) what happens to the other one?
Sharing makes strange bedfellows.
The FCC decided not to allow LPTVs to engage in channel-sharing arrangements. Only full-power and Class A stations may do so.
Strangely enough, they may share with each other. The Commission has not yet decided what to do with the technical rules if this happens. (as the vast majority of full-power stations use far more power than is allowed for a Class A.)
Strangely, they haven't decided what to do if a Class A that hasn't converted to digital yet volunteers to share. (seems to me the sharing process would inherently require the Class A station to go digital...)
Commercial and non-commercial stations may share a channel. The FCC has not yet decided whether to allow them to share a channel that's reserved for non-commercial use. However, it looks to me as if they're inclined to allow it.
The Commission anticipates future situations where a station may wish to change its city of license in order to move in with a sharing partner whose facility cannot serve the station's existing community.