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- Aerial Video Services, out of Burbank, California, is
- major supplier of the in-car cameras, wireless cameras
- and communications links for the television coverage of
- auto racing and other sporting events. During a recent
- racing series at the Texas World Speedway, AVS provided
- the microwave and communications equipment for the Prime
- Network television coverage of the races. I had a chance
- to work with the AVS crew, and check out their radios.
- If you get to attend a sporting event where wireless
- cameras or mics are in use, you might check out some of
- these frequencies.
-
- Let me explain a little about the equipment they are
- using, and what you might hear. Any time there is a
- wireless camera in use, they will be sending the
- pictures from the roving camera location to the TV
- remote truck on a microwave link. They may use the
- 2 to 2.5 gHz or 7 gHz microwave bands. In addition to
- pictures from the camera, there has to be voice
- communications to the cameraman, and sound from the
- announcer's microphone, who may appear on camera, and a
- cue channel to the announcer, so he knows when he is on
- the air. The communications from the TV director to the
- cameraman are usually referred to as the "PL". This
- stands for "party line", and is a two-way communications
- link with the director and the camera operator. It is
- usually set up as a low-power repeater, so you will
- always hear the directors calls, and the camera
- operators replies. The cue channel to the announcers is
- called the "IFB", which stands for "interrupted feed-
- back". This is usually the audio from the program that
- is being produced, along with the director or producer
- interrupting the program feed, in order to give cues to
- the announcers. This transmitter will be on as long as
- the TV production truck is operating.
-
- AVS uses mostly I-COM programmable radios. Here are
- frequencies that are programed into the units...
-
- Channel Frequency
- 1 457.525 - This ch.used for IFB 10/18,19
- 2 457.550
- 3 457.575
- 4 457.600
- 5 467.750
- 6 467.775
- 7 467.800
- 8 467.825 - Car camera control data
- 9 467.850
- 10 467.875
- 11 467.900
- 12 467.925 - AVS tech communications
- 13 467.7375
- 14 467.7625
- 15 467.7875
- 16 467.8125
-
- They also have radios programed in the 450 - 455 mHz
- Broadcast Remote Pick-up bands. At the racing I attended
- they used 455.350 as the P.L. communications to the pit
- camera. 450.350 was the input frequency to the repeater.
- Why they used the frequencies "backwards" from what the
- normal repeater frequency scheme would be isn't known.
- The car camera control data uses a 10-watt base station
- that transmits control tones to the cameras in the cars.
- You will hear a continuous carrier with DTMF (Touch-
- Tone) audio tones as the commands are sent. The
- microwaved pictures and sound from the in-car cameras
- are beamed up to a helicopter that has a microwave
- receiver on board, and then re-transmitted back down to
- the TV production truck on another microwave frequency.
- The TV truck used 123.050 to talk with the helicopter.
-
- The wireless mics that the roving announcers may use
- are Sony UHF mics in the 950 mHz band. Here is the
- channel allocations for the USA.
-
- Channel Frequency
- 11 947.250
- 12 948.250
- 13 950.250
- 14 951.750
- 15 949.000
- 21 947.750
- 22 949.750
- 23 950.750
- 24 951.250
- 25 948.500
- 31 949.250
- 32 948.750
- 33 950.000
- 34 951.500
-
- Also, for you race fans who may end up at some SCCA
- racing events, here are some assorted track frequencies
- in use at the Texas World Speedway, in College Station,
- Texas.
- 151.625 - SCCA Race Control Primary
- 151.685 - SCCA Secondary
- 151.715 - SCCA
- 464.500 - Texas World Speedway
- 464.550 - Texas World Speedway
-
- To sum up, check all of the above frequencies for
- activity next time you are at the races, or any other
- major sporting event where there might be some wireless
- cameras wandering around!
-