Personal FM System 72-76 MHz includes 1 PPA T46 FM transmitter

The Williams AV PFM PRO is a personal FM listening system designed to provide clear audio when noise or distance makes ordinary listening difficult. Intended for classrooms, work environments and home use, the supplied configuration includes one PPA T46 FM transmitter operating in the 72-76 MHz band. Its 17 selectable channels, 150 ft (45 m) listed range and adjustable audio settings support applications that need a direct, controlled listening feed.

Ideal Use Cases

The PFM PRO is suited to classrooms where a listener needs to hear an instructor from across the room, workplaces where surrounding activity can compete with speech, and home environments where distance from the speaker or audio source presents a challenge. The transmitter accepts both microphone and auxiliary signals, allowing it to handle spoken presentations as well as an external audio feed. Its battery-powered design also supports locations where permanent installed wiring is not available.

Why Choose This Model

The included PPA T46 combines straightforward controls with detailed status information. Its OLED display shows the selected channel or frequency, microphone and auxiliary input levels, battery status, microphone mute state, channel lock and dual-preset mode. Up, Down and Menu buttons provide access to volume, auxiliary input, compression, channel mode, screen timeout, brightness and default restoration settings. A separate momentary button controls power and microphone muting, while a green power LED flashes when the battery is low.

Users can select either 1:1 compression, which turns compression off, or 2:1 compression through the transmitter menu. The system also supports 17-channel or 8-channel operating modes, providing configuration flexibility for different listening environments.

Installation and Integration

Setup begins by connecting an electret microphone to the 3.5 mm mono microphone input or attaching a stereo source to the 2.5 mm auxiliary input. Microphone gain is adjustable across a 25 dB range, while auxiliary gain offers a 60 dB adjustment range. The transmitting antenna is integrated with the microphone cord, so the cord forms part of the RF system during operation.

The transmitter uses two AA batteries and includes a battery-type switch for selecting Alkaline or NiMH operation. The listed alkaline configuration provides up to 30 hours of transmitter battery life. Compatible receiver models include the PFM R31, PFM R32, PFM R33, PFM R36, PPA R35, PPA R37, PPA R35-8 and PPA R1600. Receiver and listening-accessory requirements should be matched to the intended installation.

Performance Highlights

The system provides 17 operating frequencies from 72.1 through 75.9 MHz, with a listed transmission range of 150 ft (45 m). Frequency synthesis uses a crystal reference and PLL, with stated stability of +/- 0.005%. FM modulation operates at +/- 75 kHz peak deviation, and RF output is rated at 80 mV/m at 3 m, identified as the maximum permitted by FCC rules.

Associated receiver specifications include a 75 kHz intermediate frequency, 75 kHz FM deviation, 75 microsecond de-emphasis and an AFC range of +/- 120 kHz. Listed audio output is 35 mW maximum peak into 16 ohms through a 3.5 mm stereo/mono phone jack. The receiver antenna is integrated with the attached earphone or headphone cord, and an automatic sleep mode engages after approximately six minutes without an RF signal.

What Makes It Different

The PPA T46 provides more adjustment and status visibility than a transmitter limited to a basic channel selector. Its OLED menu combines audio-level monitoring, input control, selectable compression, channel locking, two channel-count modes and dual-preset status in one interface. The enclosure specification calls for shatter-resistant PC/ABS plastic with a textured, scratch-resistant aluminum faceplate. The product data also lists FCC, Industry Canada, RoHS and WEEE approvals or directives.

The system supports multiple compatible receivers rather than restricting integration to a single receiver model. This gives buyers a defined family of PFM and PPA receiver options while retaining the same 72-76 MHz transmission platform.

Final Assessment

The Williams AV PFM PRO is a focused solution for transmitting speech or auxiliary audio where noise and distance interfere with listening. Its 17 channels, 150 ft range, adjustable microphone and auxiliary inputs, selectable compression and information-rich OLED interface provide concrete control over system operation. The supplied data explicitly identifies one PPA T46 transmitter as included, so the required receiver and listening accessories should be confirmed for each application.