User Manual

DE
DANIELS
ELECTRONICS
3-4 UHF Amplifier Instruction Manual UT-3 406 - 512 MHz
3 Turn on the power to the transmitter.
4 For high power amplifier units, follow steps 5 to 7 below. For low power amplifiers,
skip to the Output Power Alarm procedure.
5 Tune the output matching capacitor for maximum output power. This should be
approximately 8 Watts.
6 For single frequency applications, tune the input matching capacitor so that +9.5 Vdc
current is minimized without sacrificing output power. For wideband applications it
is best to tune the amplifier at the highest frequency in the band of interest and then
tune the input matching capacitor so that the +9.5 Vdc current never exceeds 1.2
amps over the desired frequency band.
7 For single frequency applications, re-peak the output matching capacitor. For
wideband applications it is best to tune the amplifier at the highest frequency in the
band of interest and then re-peak the output matching capacitor so that the +13.8 Vdc
current never exceeds 1.5 amps over the desired frequency band.
3.6.2.2 Output Power Alarm (Forward Power)
Open Collector Output
* note: the output power alarm output is factory configured as an open collector output
so a pull-up resistor may be required on transmitter pin B26 if one is not already
present.
1 Adjust R7, the output power adjustment, to the output power at which the Output
Power Alarm is to be activated.
2 Monitor transmitter pin B26, the Output Power Alarm line, and slowly turn R21, the
output power alarm adjustment, clockwise until pin B26 goes low. The alarm is now
set for the current output power of the transmitter.
Linear Output
1 Open the amplifier case to disable (open c ircuit) jumper JU2 and enable (short)
jumper JU1.
2 Monitor transmitter pin B26 with a voltmeter.
3 Adjust R7, the output power adjustment, for full transmitter output power.