User's Manual Part 1

T6T 300 Watt VHF Transmitter Page 24 Specification
AM Modes
The transmitter can operate in AM-Voice mode (standard) and AM-MSK mode (optional). The following
specifications apply to both modes unless stated otherwise. ETSI test methods specified in EN 300 676
are used where applicable.
Transmitter RF Characteristics
Output Impedance
50 ohm via an N-type connector.
RF Power Output
The RF carrier output power is adjustable in 6 W steps from 30 W to 300 W. As an option, the maximum
selectable power can be limited. Output power is automatically controlled under the following conditions:
Frequency range Variations in power remain within -0.5 to +1 dB over the operational
frequency range.
Low supply voltage Variations in power remain within ±1 dB for supply voltages between
27 Vdc and 32 Vdc. For voltages less than 27 Vdc the power
progressively reduces by up to 3 dB. When the minimum dc voltage
level is reached, the transmitter dekeys.
High VSWR Loop error can reduce power progressively by up to 3 dB. Variations
in power remain within ±1 dB into a VSWR of up to 2.5:1. At a VSWR
greater than this the output power may be reduced by 10 dB ±1 dB.
High RF PA temperature If the RF PA temperature sensor exceeds 80°C the output power is
reduced by 3 dB ±1 dB. If the RF PA temperature sensor exceeds
90°C the transmitter is de-keyed and automatically re-keyed at 70°C.
Amplifier failure If one of the three amplifiers fails, the transmitter continues to operate
at 66% of the original set power.
Rise time The power rise time from a keying contact to 90% of full power is less
than 50 ms.
Duty Cycle
Both modes 100% continuous operation.
Channel Spacing
AM-Voice mode The transmitter is capable of both 25 kHz channel spacing and
8.33 kHz channel spacing.
AM-MSK mode 25 kHz.
Offset Carrier
AM-Voice mode The transmitter is capable of offsetting the carrier frequency to provide
2, 3, 4 and 5-offset carrier.
AM-MSK mode Offset carrier is not available.
Harmonic Outputs
All harmonic outputs are less than -80 dBc.