TH50 & DB50

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Why do I get interference on TV set when dB50 Transmitter is turned on?

The dB50 transmits its signal in the FM band which is between two of your normal TV channels. The signal being transmitted can interfere with local off air TV channels if the transmitter is too close to the TV antenna. Here are some things to try:

  • Adjust channel selector on rear of the transmitter until the picture on the TV set is clear. You may have to readjust the tuning dial on the receiver until you again receive the audio through your headset.
  • Lower antenna. The shorter you make the telescoping antenna, the weaker the transmitted signal becomes. You want to lower it enough to eliminate the noise being picked up by the TV, but not so much as to make the dB50 to perform poorly or have too short a range.
  • Move the transmitter away from TV. Sometimes the transmitted signal “bleeds” in to the TV’s poorly shielded tuner. This is more often the case in older TV sets
  • Try a power strip with AC filtering. We have found that noisy AC power can get mixed into the audio and be transmitted along with the desired signal. A good line conditioning surge protector strip is good for all of your electronic equipment.

The sound coming in is full of static and weak, what’s the problem?

Most often this is a sign that the battery is either not charged, or is bad. Try replacing the battery and charging the new one for a full 10-12 hours and then see how it works.

Note: The TH50 and dB50 receivers both use a readily available battery used in many brands of cordless phone. You can usually find them at any store that sells a variety of cordless phones.

Specifications for DB50 Receiver

SENSITIVITY LESS THAN 3 MICRO VOLTS
TUNING RANGE 72 TO 76 MHz
AUDIO FREQ. RANGE 100 Hz TO 8KHz
MAX AUDIO OUTPUT 40 mw INTO 32 OHMS
STEREO SEPARATION 25dB MINIMUM
SIGNAL TO NOISE (30UV STEREO MODE) 47dB MINIMUM
TONE BOOST @ 3.5 KHz 22dB MINIMUM
DISTORTION @ 1KHz (100 KHz PP DEVIATION) LESS THAN 1%
AUXILIARY INPUT RANGE .05V TO .150V RMS
BATTERY 3.6V NiCAD RECHARGEABLE

Specifications for DB50 Transmitter

FREQUENCY 10-CHAN PLL (MHz) : 72.096, 72.186, 72.276, 72.366, 72.456, 72.546, 72.636 72.726, 72.816, 72.907
DEVIATION 100 KHz PP
HARMONIC AND SPURIOUS SIGNALS 60 dBc MINIMUM
EQUALIZATION 6dB/OCTAVE REF. @ 2KHz
AUDIO INPUT L/R 50mv – 2.00 V RMS
AUTO LEVEL CONTROL ATTACK TIME 10 msec.
AUTO LEVEL CONTROL RELEASE TIME 6 sec.
MAXIMUM OUTPUT POWER 80,000 uv/METER @ 3 METERS
POWER REQUIREMENTS 9VDC 100ma