[R-390] Frequency assignments web site

[2002tii]

Roy wrote:

>The site tells that wireless microphones operate on the frequencies of
>the new DTV broadcasts, and that trouble is going to appear for
>unsuspecting wireless mic users.

Digital television (DTV) stations operate on the same, 6 MHz channels 
as analog stations (actually, after February 17, 2009, DTV stations 
will operate only on channels 2-51 -- channels 70-84 were reassigned 
to other uses in the early 1980s, and channels 52-69 were reassigned 
more recently).  Many wireless mics operate, and have been operating, 
on vacant TV channels for decades.  This is possible because, like 
radio spectrum, TV spectrum is assigned in geographically-separated 
areas so that the transmitters do not interfere (much) with each 
other (the exception being being the AM broadcast band, where 
nighttime DX reception is nothing but interference; the FCC does not 
protect DX coverage).

The problem for wireless microphones is not digital television 
(DTV).  The problem is that the FCC, driven by large 
broadband-content interests (Microsoft, Google, Dell, HP, Intel, 
Philips, Earthlink, Samsung etc. -- see "White Spaces Coalition"), 
wants to use channels 2-51 in unused geographic areas -- "white 
spaces" -- for "last mile" broadband services, like a giant Wi-Fi 
system.  The solution they proposed is for the new "TV Band Devices" 
to (i) consult a database to determine which channels are available 
for use at a given location, and (ii) monitor the spectrum locally to 
confirm that no legacy wireless microphones, video assist devices, or 
other emitters are present. If a transmission is detected, the device 
may not use the 6 MHz TV channel in which the transmission was 
received.  There is some controversy over whether workable TV Band 
Devices have been demonstrated.

Besides the objections from wireless microphone users (theaters, 
broadcasters, touring companies, sports teams, etc.), broadcasters 
complain that TV Band Devices will cause unacceptable interference to 
over-the-air DTV broadcasts.

Nevertheless, the FCC is hell-bent on implementing last-mile 
broadband services using TV Band Devices, and is moving relentlessly 
in that direction.  In fairness, it should be noted that the FCC has 
designated other frequencies for wireless microphones, video assist 
devices, and the like.  Of course, some users are not anxious to junk 
their existing TV-spectrum systems to move to the new frequencies.

Best regards,

Don