6
TX AUDIO ALIGNMENT
Levels > Radio TX Out Level:
If the radios TX input impedance is known then set JP-11 accordingly, if the
impedance is unknown, start by opening impedance jumper JP-11 and programming the VAE-10 with the “Radio
TX Out Level” set to 200mVpp under the 100% modulation heading. The “Radio TX Out Level” needs to be set
low so that the transmitter is modulated below its maximum deviation, you can then slowly increase the “Radio TX
Out Level” to the point where the limiter in the radio keeps you from increasing the deviation any more.
Record a message on the VAE-10 (page 8) which will be long enough to adjust the TX modulation when played
back. Activate the emergency input J3:1 and when the VAE-10 has caused the transmitter to begin transmitting,
check the deviation of the transmitter using the service monitor. If the deviation is below the full system deviation,
adjust “Radio TX Out Level” up by approximately 500 mV p-p increments until full system deviation is obtained. If
full system deviation cannot be obtained close jumper JP-11 and start over with the TX out level set at 200mVpp
Once full system deviation is obtained adjust “Radio TX Out Level” down by 100mVpp increments until you see a
drop in full deviation, at that point start going up with the “Radio TX Out Level” one step at a time (approximately
15 mV p-p) until full system deviation is obtained again. This level should now be at point where the limiter just
starts to limit deviation.
Note:
Most mobile radios and base stations will have low input impedance which will require jumper JP-11 to be
closed.
