User's Manual Part 1
Table Of Contents
- Health and Safety
- Customer Support
- Abbreviations
- Overview
- Specification
- Operation
- Overview
- T6T VHF Amplifier
- Drive Assembly
- Setting Up and Operation
- Normal Operation
- Using the Scroll/Select Switch
- Screen Protocol
- Menu System
- Menu Lock Screen
- Control Screen
- Notes for Setting Up the Transmitter
- Changing the Transmitter’s Operating Frequency
- To Store and Recall Frequency Channels
- To Initiate a BIT Test
- Standby Mode
- Settings
- AM-Voice Settings Procedure
- AM-MSK Mode Settings Procedure
- Mode 2 Settings Screen
- Mode 3 Settings Screen
- Polarities Screen AM-Voice and AM-MSK
- Mode 2 and Mode 3 Polarity Settings
- AM-Voice and AM-MSK BIT Screen
- Mode 2 and Mode 3 BIT Screen
- Software Configuration Screens
- Band Edges
- BIT Status Warning Screens
- Installation
- Warnings and Cautions
- Introduction
- Installing the Transmitter
T6T 300 Watt VHF Transmitter Page 75 Installation
Connecting
A coaxial cable connects each amplifier to the combiner’s three inputs (marked IN) as shown in Fig 17.
These cables are part of the phasing harness, part number 17L13000006.
The cables used to connect from the amplifiers to the combiner are critical length. Use only
the cables supplied by Park Air.
Connecting the Antenna
The combiner’s antenna connector is an N-type socket suitable for connecting a 50 ohm antenna.
The antenna used with the transmitter must be installed such that the resultant radiated field
strength is below 10 W/m² in areas normally accessible to personnel.
The RF field strength from the antenna can be predicted from the equation S=1.4PG/4πR
2
[Where S = power density; P = power input to antenna; G = antenna gain; R = distance
to centre of radiation and 1.4 = multiplication factor for average power based on a
modulation index of 90%.]
Based on this formula for a 300 watt transmitter and using a 0 dBi antenna, the predicted safe
distance from the centre of radiation would be approximately 1.8 m for a field strength of 10 W/m
2
(1 mW/cm
2
).
This meets the requirements of Health Canada Safety Code 6 for RF and microwave exposed
workers. For persons not classed as RF and microwave workers and including the general public
the limit is 2 W/m
2
(0.2 mW/cm
2
) which increases the minimum safe distance to 4.1 m.
Further information on calculating the field strengths and power levels can be found in Health
Canada Safety Code 6 'Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the
Frequency Range 3 kHz to 300 GHz', and also in FCC document OET Bulletin 65.
Caution
Critical Length Cables
WARNING
Antenna Radiation