Справочник Пользователя для Codan Radio Communications VT-3H040-S-HSO

VT-3H040 VHF Amplifier Instruction Manual     IM20-VT3040AMP 

1-1 

 
1.1 Introduction 
 
The VT-3H040 Amplifier provides the final stage of RF amplification and filtering for the  
VT-3H040 and VT-3H040 Transmitters. The amplifier operates over one of two distinct 
frequency ranges; either 29 to 38 MHz or 38 to 50 MHz, depending on which of the two lowpass 
output filters is installed. The output power is set to 3.0 Watts by means of an externally 
accessed control. The VT-3H040 Amplifier is housed in a machined aluminum case that ensures 
optimum RF shielding, provides a good ground, and also acts as a heatsink. 
 
Additionally, the VT-3H040 Amplifier is equipped with output power and VSWR sensing lines 
which can be individually configured as open collector or linear outputs. The internal VSWR 
sensor protects the amplifier from high antenna VSWR by approximately halving the amplifier's 
RF gain when a VSWR overload condition is present. 
 
Output filtering for the VT-3H040 Amplifier is provided by the Output Lowpass Filter Board. 
The Output Lowpass Filter Board is mounted in a separate compartment of the amplifier case in 
order to provided maximum attenuation of harmonic and other spurious signals. 
 
Refer to Section 4.4 "VT-3H040 Amplifier Schematic Diagram” for the amplifier and Section 
4.2 for the Output Lowpass schematic diagram. 
 
 
1.2 Performance 

 
Type: 

    MT-3 

series 

VHF 

Amplifier 

module. 

 
Compatibility:  

 

 

MT-3 series Transmitter Main Board, OS-3H040 Synth. 

 
Frequency Range: 

 

 

29.0 MHz to 38.5 MHz or 37.5 MHz to 50.0 MHz. 

 
RF Power Output: 

 

 

3.0 Watts Fixed (± 1.5 dB with temperature and supply 

 

 

 

 

 

voltage). 

 
RF power Input: 

 

 

nominal level adjustable from +4 dBm to +10 dBm,  

 

 

 

 

 

held within +/- 2 dB of nominal. 

 
Output Impedance and VSWR: 

50 Ω, Type N connector; 3:1 max. VSWR. 

 
Input /Output Isolation: 

 

> 60 dB 

 
Duty Cycle: 

100%: Continuous operation from -30˚ C to +60˚C  
(optional -40°C to +60°C)