16-06-2014, 10:59 AM
MDERN ENGINEERING & MANAGEMENT STUDIESSeminar on RADIO COMMUNICATIONS
1378139522-RadioCommunications.ppt (Size: 953.5 KB / Downloads: 11)
Radio Bands
FRS
GMRS
CB
Commercial
Commercial – Trunking
Aircraft
Cell phone
FRS
Family Radio Service
A sub-set of GMRS
Very low power – ½ watt (read – short range!)
Millions in use!
GMRS - who can use?
The General Mobile Radio Service (GMRS) is a land-mobile radio service available for short-distance two-way communications to facilitate the activities of an adult individual and his or her immediate family members, including a spouse, children, parents, grandparents, aunts, uncles, nephews, nieces, and in-laws
Fees: $75 for 5 years to FCC
GMRS – what can you use?
If you operate a radio that has been approved exclusively under the rules that apply to FRS, you are not required to have a license. FRS radios have a maximum power of ½ watt (500 milliwatt) effective radiated power and integral (non-detachable) antennas.
If you operate a radio under the rules that apply to GMRS, you must have a GMRS license. GMRS radios generally transmit at higher power levels (1 to 5 watts is typical) and may have detachable antennas
CB
Citizens Band
Been around for years
Antennas very inefficient on portables
Most conversations not fit for family
Amateur Radio
Bands of interest are VHF and UHF, can be high power (5 watt portable, 50 watt mobile)
Either is fine for ballooning
Equipment relatively inexpensive
Can be used for telemetry - GPS tracking, TV and other fun stuff
Can set frequencies to avoid conflicts
Can go through repeaters to increase range
Commercial
A company or organization can obtain
license for all “members”
Anyone can use your radios under your individual or group license
Equipment medium priced, a lot is
available used as business users switch
to other communication methods
Radios must be programmed by licensed
Radio Shop
Commercial – Trunking
Works through repeaters on a mountain or tower.
Private – only “your” radios hear or talk to each other
Covers a large area – if you can see the tower, you can talk to any other radio that can see the tower
No license required, the system operator has them
Requires a monthly fee per radio, usually about $15
Due to the monthly costs, probably only for commercial operations
Aircraft
Balloon is covered as aircraft, no license is needed
Chase vehicle: Aviation Support Ground Station license is required
Cost: $150 for 5 years