1. Lecture 3
Radio Communications

2. Basic Communications Course
Agenda
Introduction to Radio
Radio Procedures
Radio Equipment

3. Radio Equipment Radio Equipment falls into 2 main categories:
Base Stations
Mobiles

4. Base Stations Fixed installations at Squadron or Unit HQ’s.
Chosen for reliability, stability and power output.
Range for UHF or VHF Base Stations may exceed 50 Km.

5. Base Station

6. Mobiles Mobile installations fall into 2 sub-categories.
Vehicle Installations.
Man portable equipment.

7. Vehicle Equipment Chosen for reliability and robustness.
Must be reasonable efficient as it is usually powered from the vehicle’s battery.
Effective range up to 30 Km.

8. Vehicle Installation

9. Man Portable Equipment
BACK-PACK EQUIPMENT.
Chosen for reliability and robustness.
Choice of equipment depends on desired range, service life of the battery and duty cycle.
Range up to Km.

10. Man Portable Equipment
HAND PORTABLE TRANSCEIVERS.
Range of about 1-5 Km.

11. Duty Cycle
The duty cycle is the ratio between transmit and receive time, expressed as a percentage.

12. Duty Cycle A usual duty cycle of 5/10/85% is common. 85% Standby
5% Transmit
10% Receive

13. Duty Cycle
Back-pack equipment may have an operational capacity of hours on a 95-98% duty cycle.

14. Duty Cycle
Hand portable equipment may have an operational capacity of 6-8 hours on a 95% duty cycle.

15. Safety Precautions when using Hand Portable Equipment
The type of batteries used for hand held and mobile equipment require a high current capacity.
When they are not attached to the radio they should be handled with care.

16. Safety Precautions NEVER:
Charge lead acid batteries in a confined space.
Carry loose batteries in pockets or bags.
Short terminals together.

17. Safety Precautions ALWAYS:
Cover battery terminals in transit or when not in use.
Keep lead acid batteries upright.
Charge with the correct type of charger.

18. Operating Ranges The frequency band in use.
The power output of the transmitter.
The sensitivity of the receiver.
The efficiency of the aerial system.
The prevailing atmospheric conditions.
The position of the aerial.

19. Aerial Position
Standing too close to metal objects, buildings or granite Tors can restrict range dramatically.
VHF and UHF are limited to “line of sight” communications.
How can we increase the range of such equipment?
Increase the height of the aerial.

20. Use and Treatment of Equipment
Radio equipment is expensive to buy and maintain.
What can you do to prolong the life and protect the equipment entrusted to you?

21. Use and Treatment of Equipment
NEVER:
Hold a set by its aerial.
Leave a radio unattended.
Alter the settings of the controls unless instructed.
Transmit close to another radio.
Charge a partially discharged battery.

22. Use and Treatment of Equipment
ALWAYS:
Switch off after use.
Keep dry and clean.
Turn off additional radios at the same location on the same channel.