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Digital Television will provide television viewers an entirely
new level of clarity and program options. Unfortunately, DTV is not a blessing for
wireless microphone, wireless IFB/In Ear Monitor and wireless intercom users. In
addition, the FCC is taking the transition to DTV as an opportunity to recover spectrum
for other uses. The first use the FCC is making available is TV channels 63, 64,
68 and 69 for Public Safety Organizations.
What does DTV mean to wireless microphone users? DTV signals occupy
an entire 6 MHz television channel. Compare this to an analog NTSC signal that barely
fills a 6 MHz channel. DTV stations are comming online now and are wiping out spectrum
that was previously available for wireless microphone users. The graphic below shows
a real comparison between a DTV signal and NTSC signal from the same city.
During the next several years , more and more wireless users will
experience problems ranging from increasingly noisy operation to total failure of
their wireless systems. Commercial broadcasters (television stations) will introduce
DTV over a period of about five years. During this first five years and a subsequent
five year transition period, broadcasters will use both existing analog and new
digital transmission systems. At the end of the ten year transition period (2006)
existing analog transmitters will be turned off.
What does this mean for the wireless system user?
Wireless microphones and related systems operate as "secondary" users.
Even if you hold a license for your wireless equipment, it must not cause interference
and must accept any interference. The FCC takes minimal notice of wireless mic users.
No protection from commercial broadcasters is provided even if you hold a license
for your frequencies . This means that we are on our own as far as interference
is concerned. There is no one that will listen to our complaints, so it's no use
complaining.
What do we do? We as wireless users simply have to plan ahead a
little farther. If you are planning the purchase of a new wireless system, pick
frequencies that aren't expected to take interference. If you own wireless equipment
now, find out if your frequencies might take interference from DTV or public safety
broadcasts. If you find that your equipment is expected to take interference, considering
changing frequencies to avoid the problem. Frequency agile wireless systems will
be extremely useful if you decide to purchase new equipment. However, even frequency
agile systems should be planned around DTV. An agile wireless microphones capabilities
would be wasted if 90% of it's available frequencies are stepped on by DTV signals.
Remember, time is critical. If you can avoid the problem before
your equipment is affected, you'll have minimal down time. If you wait until you
take interference, chances are high that service centers like Professional Wireless
and the wireless manufacturers will not be able to respond quickly to your needs.
It takes a minimum of three days to grow a new crystal, plus shipping and installation
time. Multiply the time to service one wireless system by the number of users that
waited until the last minute and you can see that service times are not going to
be a quick as they are today.
Professional Wireless Systems can assist you in planning ahead
for DTV. We will discuss your needs with you and help you with a solution including
frequency coordination and frequency changes. Our technical staff is the best in
the southeast. We service all types of wireless microphones, intercoms, in ear monitors
and IFB's in house for quick turn around and quality service.
For the do it yourselfers, the following links point to the original FCC document
concerning DTV channel assignments. Please keep in mind though, that this information
is only one part of the solution. Low power television stations (LPTV) and translator
stations are not listed in this report. Many of these broadcasters are also being
forced to move to new frequencies because of DTV. These stations should be included
in your frequency coordination efforts as well. Also, since the publication of this
list, many channel assignment changes have been made. PWS can assist you with determining
the latest DTV channel assignments for your specific location.
On August 7, 2007 the FCC announced the Final Assignment of
Digital Television Channels.
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Please note: These links point to files located on the FCC's web server. Their availability
is not guaranteed by Professional Wireless Systems.
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