PERSONAL PA
®
VALUE PACK System
Architect and Engineering Specifications
The system shall consist of a single FM transmitter with flexible antenna, four (4) personal receivers with batteries and
earphones, audio cable (RCA to RCA), wall plaque, and instruction manual.
Transmitter
The FM transmitter shall be contained in a black, rack-mountable, metal enclosure. A rack panel shall be available to mount
up to four transmitters within a single EIA rack space.
The transmitter shall provide single-channel operations at the following frequencies, selectable by internal switches: 72.1,
72.3, 72.5, 72.7, 72.9, 75.5, 75.7, 75.9, 74.7, or 75.3 Mhz. Frequency modulation shall be no more than 75 kHz. Frequency
stability shall be ± .005% over 0-50˚C. Pre-emphasis shall be 75 µS. Frequency response shall be 100 Hz – 15 kHz ±3 dB, with a
maximum distortion of 1% THD. The signal to noise ratio shall be 55–60 dB as measured with a PPA R7 Receiver. The transmitter
shall provide a nominal range of 300–500 feet (90–150 m), with a maximum RF field strength of 8000 µV per meter at 30
meters, 20 mW typical.
The transmitter shall have a microphone input and line–level input. The microphone input shall be a 3.5mm mini phone jack
supplying positive DC power for electret mics. The mic input level shall be 1–10 mV, nominal. The line-level input shall be a Hi
Z, unbalanced RCA jack with an input level of 0.1–1 Vrms, nominal. The transmitter shall have a pot–style, screwdriver-
adjustable input attenuator. The transmitter shall have two antenna outputs. The first shall be a thread mount for a “rubber
duckie” flexible whip antenna. The second shall be a thread mount for an optional 75 Ω coaxial antenna using RG-59 cable.
The maximum cable length of the optional coaxial antenna shall be no more than 400 ft. (140 m).
The transmitter shall be powered by an external 105-130 VAC, 50-60 Hz, .5 W power supply, connected via a concentric DC
plug. The transmitter should not have a power switch. The transmitter shall have a LED lamp to indicate “power on.” The
transmitter shall also have a LED lamp to indicate the presence of an audio signal.
The transmitter shall carry a five year parts and labor warranty. The transmitter shall be the Williams Sound Corp. Model PPA
T17.
Receivers:
The receiver shall be housed in an impact resistant plastic case with a hinged battery door that does not separate from the
receiver. The receivers shall be a body-pack type and include a belt-clip case for hands-free operation. The receiver shall
have a 3.5 mm mono phone jack and accommodate low-impedance mono earphones, headphones, and neckloop
telecoil couplers. The 3.5 mm phone jack shall also serve as a charging jack for rechargeable batteries.
Receiver frequencies shall be pre-tuned and adjustable by means of an internal tuning coil. A four-channel receiver model
shall be available for use with the system.
The receivers shall receive FM signals in the 72–79 MHz Audio Assistance band with 75 µS de-emphasis. The receivers shall
provide a maximum output of 250 mW at 16 Ohms with an earbud-type earphone. The system electrical frequency response
shall be 100 Hz to 10 kHz, ±3 dB and the signal to noise ratio shall be 50 dB at 10 µV.
The receiver shall be covered by a five year parts and labor warranty, excluding earphones, headphones, batteries, and
chargers. The receiver model shall be either the Williams Sound Corp. Model PPA R7 or Model PPA R7-4.
How the System Works:
The PERSONAL PA Value Pack System
connects to your existing sound system or
can be used with its own microphone (not
included). The signal from the sound system
is broadcast as an FM radio signal over a
distance of 300–500 feet (90–150m).
Listeners use R7 or R7-4 pocket receivers
and earphones to hear the message
directly, with reduced background noise
and without seating restrictions.
