Handbook for Sound Engineers

1574 Chapter 43

producer to talk to the talent during a voice-over
commentary either on or off camera in a live or taped
production. Sports broadcasts typically use many chan-
nels of IFB to communicate with announcers in various
locations on the field and in booths. When recording
live performances on stage or in a studio, musicians can
hear direct queues from the conductor or producer as
well as the individual music mix designated for them.
For television broadcasting, IFB queues on-camera
announcers and is used between on-scene reporters and
the in-studio anchor and studio director. IFB is
controlled by the talker or person in control while the
listener has no control over IFB.

43.2.5 Wireless Broadcast Intercom System

There are two types of wireless intercom systems. The
first type provides a one-way, listen-only feature for the
remote stations. In this system, the intercom is wired to
the master transmitter. All communications on the
intercom line are relayed to all of the wireless receivers.

A one-way intercom is typically used for people who

need to know what is going on, but don’t need to talk

back.

The second type of wireless intercom is a two-way

system. In this configuration, the base unit and the field

units can both talk and listen to each other in a full

duplex mode. This requires two frequencies, a talk

frequency and a listen frequency.

Wireless systems can stand alone, but when

connected to a wired intercom system, the wireless link

is virtually transparent to the user. The FCC has

approved the 150–216 MHz band for broadcast use with

over 1700 possible frequencies available. This band is

relatively free from external radio and electrical inter-

ference. Transmitter output power is limited to 50 mW.

Operating distances between units vary with the envi-

ronment. If it is in open areas, it is possible to have good

reception up to 2000 ft. However if the area includes

walls, obstacles, and other radio transmitters, transmit-

ting distances are more likely to be 150–300 ft. Battery

life on belt packs should be over 20 h as these units are

Figure 43-14. Digital matrix system. Courtesy Clear-Com Communication Systems.

POWER SUPPLY

TEL-14EMPTYEMPTYEMPTYEMPTYEMPTYEMPTYCCI-22EMPTYRLY-6FOR-22

ECLIPSE PICO

CONTROL PANEL WITH MIC

CAM-1CAMERA CCU (4 WIRE)

4-WIRE ISOLATION TRANSFORMER

PHONE-1 PHONE-2

INTERFACE FRAME

CAM-2CAM-3

SINGLE CHANNEL BELTPACK CH-A

CC-95 FOR CAMERAS(NEEDS MODIFICATION X3)

DIRECTOR

AUDIO

PSU-101

PSU-101

TWO-WAY RADIO

ENGINEERING

LIGHTING DIRECTOR

BLACK BOX DIR.

SINGLE CHANNELBELTPACK CH-B

VOICE OVER IP

ANTENNA

PD-2201

WI

CELL TYPE WIRELESS

C^

PD-2201 ANTENNA

ANTENNAANTENNA

EITHERNET VOIP

CONNECTIONS VIA

STANDARD CAT-5 CABLE

NORTH WIRELESS

SOUTHWIRELESS

REMOTE PC

TALENT IFB

CONTROL PANEL

CONTROL PANEL

CONTROL PANEL

CONTROL PANEL

STAGEHANDS LIGHTS

RELAYS OUTTO QUE LIGHTS

WIRELESS INTERCOM WIRELESS INTERCOM WIRELESS IFB

(^80478047)