Nady Systems ALD-800 Owner's Manual - page 4
7
ARCHITECTS AND ENGINEERING SPECIFICATIONS
ALD-800 Transmitter
The transmitter operates on the 72-76 MHz auditory assistance frequencies. Transmitted field
strength shall not exceed 8000 µV/m at 30 meters. The operating frequency is factory selectable
to eight different channels by means of an internal switch.
Maximum FM deviation should not exceed 75 KHz. Transmitter signal pre-emphasis is 75 µS.
Frequency stability is controlled by a phase locked loop synthesizer with crystal reference and
accurate within ±.005% over 0-50 degrees C. The transmitter provides a permanently mounted
telescoping whip antenna.
The FCC approved transmitter is powered by a UL and CSA listed AC wall transformer providing
9V DC input to the transmitter via a 3.5mm DC jack. The transmitter includes a 1/4” line-in jack,
mounted on the rear panel, and 1/4” electret condenser microphone jack with 9V DC power (at
1.0 mA), mounted on the front panel. Also included, is an adjustable audio level control and a red
LED ‘power on’ indicator. The model number is ALD-800.
ALD-800 Receiver
The receiver operates on a single frequency in the 72-76 MHz auditory assistance band.
Frequency stability is controlled by a phase locked loop synthesizer with crystal reference and
accurate within ±.005% over 0-50 degrees C. The receiver de-emphasis is 75 µS. The receiver
provides a 3.5 mm headphone output jack mounted on the top panel.
The receiver is powered by a 9V alkaline battery. The receiver has an OFF/ON/VOLUME control
mounted on the top panel, LED lamp to indicate battery strength, and an antenna shall be inte-
gral to the earphone/earbud cord. The receiver model number is ALD-800.
OVERALL SYSTEM PERFORMANCE
Frequency Response ..........100 Hz-15KHz ± 3 dB
Signal to Noise Ratio ..........60 dB
Total Harmonic Distortion ..< 0.5%
RF Carrier Frequencies ......Eight channels between
72-76 MHz. Channel AA:72.1,
BB: 72.3, CC: 72.5, DD: 72.7,
EE: 72.9, FF:75.5, GG: 75.7,
HH: 75.9
Frequency Stability..............Better than .005%
Modulation ..........................FM ± 75 KHz max
Operating Range ................Up to 300 feet line-of-sight
ALD-800 TRANSMITTER
Mic Input ..............................Connector: 1/4“ phone jack.
Impedance: low impedance,
unbalanced, with 9V DC at
1 mA for condenser mic.
Line Input ............................Connector: 1/4“ phone jack.
Impedance: 100 K
Ω
,
unbalanced.
Power Output ......................80,000 µV @ 3 meters
Controls ................................Power on/off, audio input
gain adjust
Indicators ............................Power On LED, Audio
Modulation LED
Antenna ................................Permanently mounted
telescoping whip
Power Requirement ............9 VDC, regulated @200 mA,
AC-ALD800 adapter provided
Dimensions ..........................1.25" H, 8.25" W, 4.25" D
(3.175 x 20.9 x 10.8 cm)
Weight ..................................18.2 oz. (500 g.)
ALD-800 Receiver
Controls ................................Combination volume/on-off
wheel
Audio Output........................250 mW max into 16 ohms
Connectors ..........................3.5 mm mini jack for
earphone output
Earphones ............................Mini binaural earbuds
Antenna ................................Integral with earphone cord
Indicators ............................LED power on indicator
Sensitivity ............................2 µV for 12 dB Sinad with
squelch defeated. Squelches
at 10 µV for min. 50 dB S-N
ratio
Mute Threshold....................8-10 µV
Power Requirement ............9V alkaline
Battery Life ..........................17-20 hours w/alkaline battery
Dimensions ..........................3.35” H, 2.75” W, .75” D
(8.5 x 6.5 x 2.25 cm)
Weight ..................................2.65 oz. w/out battery (73 g.)
SPECIFICATIONS
6
ALD-800 Receiver (Front Panel)
ALD-800 Receiver (Top Panel)
Adjusting Earphones Volume
Listen for your program source, and adjust receiver volume to a comfortable listening level.
NOTE: A slight hum may be heard if the receiver is used within six feet of the transmitter.
This is normal and does not affect performance.
Testing Receiver Range
Wearing your receiver and earphones, walk around your seating area and listen for audio quality.
In certain areas of the room the audio may disappear or “drop out.” This is a normal occurrence
whenever radio signals are transmitted inside a building. If you step away from the “drop out”
zone, the audio will return.
NADY ALD-800 RECEIVER
2
Earphone Jack
4
Power On LED
3
ON/OFF
Volume
1
Battery Compartment - On Bottom