Operating instructions

RF Technology PA501 Page 12
4.4.2 Frequency Range 4 SPECIFICATIONS
4.4.2 Frequency Range
Model Frequency Range
PA501A 400-450MHz
PA501B 450-512MHz
4.5 Antenna Impedance
Nominal load impedance is 50Ω SWR 1.5:1 or better. The PA501 will operate with a
VSWR of 2:1 at all phase angles. The forward power will reduce as reverse power rises
above acceptable limits, typically at an SWR of about 2.5:1.
4.6 Output Power
Nominally 100 Watts, preset adjustable from 25 to 120, typically 125 Watts maximum.
Gain is >8.5dB.
4.6.1 Transmit Duty Cycle
The transmitter is rated for 100% duty cycle (continuous operation) at 100W output for
air temperature below 40C. Derate linearly above 40C to 50% at 60C. At 125W output,
limit to 80% duty cycle or 2 minutes operation at 40C, derate to 40% at 60C.
4.7 Spurious and Harmonics
70dBc minimum at any harmonic of the transmit frequency.
4.8 Heatsink Temperature
The heatsink temperature can rise to 80C without affecting operation, except for
derating based on air-temperature as noted in section 4.6.1 above. Shutdown will occur
at heatsink temperatures exceeding approximately 90C.
4.9 ALC Output
The ALC is intended for connection to the T500. It supplies a voltage which decreases
with increasing power or temperature. Voltages below 6V should reduce drive power,
at a rate of approximately 6 dB/Volt, with voltages below 1V producing a minimum of
25 dB attenuation.