ALT72 Assistive Listening Transmitter
The ALT72 is a high quality, commercial grade transmitter that performs superbly in applications where music/message fidelity is a must. The ALT72, conveniently designed as a desktop unit, also provides easy operation via front panel push button controls and includes 7" flexible whip antenna. The ALT72 has an external antenna available, and optional two unit 19" rack mounting accessory also available.
Architectural and Engineering Specifications
The Transmitter shall operate in the 72-76 MHz Auditory Assistance Band as approved by the FCC. Specifically, the transmitter shall operate on the wideband channels spaced at 100 kHz increments on frequencies of 72.1 to 72.9, 74.7, and 75.5 to 75.9 MHz. The transmitted field strength shall not exceed 80 millivolts per meter at a 3 meter distance. The operating channel shall be selected and displayed by a front panel switch, a limiter and 2:1 compressor shall be included and switch selectable. The transmitter shall be FCC and Industry Canada approved.
Maximum FM deviation shall not exceed ±75 kHz. Frequency stability shall be controlled by a phase-locked loop frequency synthesizer with crystal reference and shall be accurate within ±0.001% from 0-50° C. The transmitter shall permit fitting of a 7" flexible whip antenna mounted through the top cover of the unit, or permit connection of an optional magnet mount antenna, with coaxial cable, to a rear panel connector. Only the particular antenna type intended for this connection shall be specified.
The transmitter shall have XLR connectors for balanced audio inputs and RCA Phono connectors for unbalanced audio inputs. The transmitter shall provide a GROUND LIFT switch for the XLR inputs. There shall be a front panel control to adjust the audio input level with an LED OVERMODULATION indicator.
The transmitter shall be powered by an external AC line to 12 VDC power adapter. The rear panel shall have a power switch and front panel display indication when power is active. The transmitter shall be rack mountable in a standard 1 RU rack steel package. The R.L. Drake ALT72 Assistive Listening Transmitter is specified.
Features and Benefits
- FM Assistive Listening Component
Can Be Used Indoors or Outdoors, in Bright Light and Without Line of Site restrictions. - Operates Within 72-76 MHz
FCC Designated Frequency Range for Assistive Listening. - Coverage of 700,000 Square Feet
Insures That Message is Heard By Everyone in the Audience. - Powerful RF Output
Eliminates Need for Additional Costly Equipment in Larger Venues. Maximum Output Allowed by the FCC. - Both Unbalanced & Balanced Audio Input
Easily integrated into existing audio system. - Front Panel Channel Switch
Ensures easy programming and verification of desired channel. - Desktop Unit (Optional 2 unit Rack Mount Kit Available)
Allows the system to be conveniently relocated as needed. - Low Distortion Limiter
Prevents overmodulation. - Audio Compressor
Can be selected to increase intelligibility in noisy listening environments.
| ALT72 System Features and Specifications | |
|---|---|
| Selectable Frequencies: | 10 channels available: 72.1 to 72.9, 74.7, and 75.5 to 75.9 MHz. |
| Frequency Selection: | Selectable by front panel channel switch. |
| Frequency Generation: | PLL Synthesis |
| Frequency Stability: | ±10 ppm, 0° to 50° Celsius (32° to 122° Fahrenheit) |
| Tuning Step Size: | 100 kHz |
| Modulation: | FM, 180KF3E |
| FM Deviation: | ±75 kHz, maximum |
| Pre-Emphasis: | 75 µSec. |
| RF Field Strength: | 80 mV/m @ 3 m with supplied antenna or optional magnetic mount antenna |
| Input Limiting: | Switch selectable, low distortion. |
| Audio Compressor: | Switch selectable, 2:1 compression range limited. |
| Audio Inputs: | XLR and RCA Phono |
| Frequency Response: | 20 Hz to 15 kHz, ±3 dB referenced to a standard 75 mSec pre-emphasis curve |
| Ultimate S/N Ratio With Drake Model MR306 Receiver: | >60 dB |
| Total Harmonic Disortion: | Less than .25%, typical |
| Power Requirement: | 12 VDC @ 250 mA, by supplied wall adapter |
| Antenna: | Flexible 7-inch whip antenna (magnetic mount antenna is optional) |
| Dimensions: | 1.55 inches (39.4 mm) Height x 7.25 inches (184.2 mm) Width x 5.125 inches (130.2 mm) Depth |
| Weight (with antenna removed): | 18 ounces (0.51 kg) |
| Coverage Area: | 700,000 square feet (65,032 square meters) |
Specifications, price, and availability are subject to change without notice or obligation.
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