The FCC’s repack channel assignment plan is causing headaches for many broadcasters. However, a creative engineering approach can resolve many of these problematic assignments, according to Dennis Wallace, a partner at engineering consulting firm Meintel, Sgrignoli & Wallace. To recap, about 987 TV stations are changing channels. Thirty winning auction bidders are moving from UHF to VHF and 957 non-winning stations are moving to a different UHF channel. Many “in-core” stations need to change channels to accommodate stations moving into core spectrum, according to Wallace.
Speaking at the IEEE Broadcast Symposium in the Washington, D.C. area Tuesday, Wallace said tighter packing of stations in less spectrum will likely lead to increased adjacent channel and co-channel interference. Especially problematic are Channel 14 assignments. Fifteen stations are remaining on CH14 and 33 more are slated to move to that channel, according to the FCC’s repack assignments.
Wallace cited a “long history” of interference to CH14 TV stations from land mobile operations, which are immediately adjacent to the TV spectrum with no guard band in-between. Many new CH14 assignments are in large urban areas with a big public safety user base of 450-470 MHz land mobile operations.
Creative solutions to possible interference involve potential station channel swaps, directional antenna pattern changes or a change in antenna heights, suggested Wallace. Often such channel swaps are possible if the station that wants the change, agrees to pay for necessary antenna modifications of the other station.
October 12, 2017