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Re: Radio communication for the riders....?
The walkie talkies what we see now in the hands of the cops and others are work in the frequency band of VHF and UHF. (Very High and Ultra HIgh Frequency).
Our old radio sets at home are utilizing the HF. The new FM boom is in VHF but in the lower frequency band ( not to take your brains out!)
HF use the ground waves and reflected waves from the ionosphere, hence very large area can be linked using proper timing and frequency.
Whereas, the small walkie talkies are limited with power( the mopeds!!) and the communication is possible only at limited distance of line of sight.
As Yogesh asked, we cannot predict the coverage of two walkie talkies , since it depends on many factors. Not 10 to 20, but 100s are possible, if one of the equipment is at high altitude. In the olden motor rallies, the controller used to sit at the highest peak which will cover the sectors below and Radios are used to link with the TCs.
In India, to keep a communication equipment you need license, issued by the Ministry of Communication &IT. Even the Motorola PMR , mentioned by anupam require Commercial operating license, but easier to get it cleared.
Ham Radio or Amateur Radio is a hobby all around the world, where radio is used for establishing friendship. Again license is a must. As per the present rule, a girl or boy above 13 years can attend the qualifying examination and obtain the license. If you want to operate the HF for international contacts then higher grade of the licence is required and study of Morse code become essential. The written exam is two part. Basic electronics as first part and Radio operating procedure as second part. It is simple....13year student means normally standard viii !! License fee and all are nominal Rs. 20-40 per year for 24 hour of communication, (the cheapest of the possible?).
Yes it takes little pain to go through all these... But once you cross, then you get a unique identity-the call sign and a photo licence card with the Asoka chakra marked on the top-valid all over the country as a proof of identity.
The equipment will cost less than 10,000 for the Walkie talkies and almost same for the fixed/mobile mounting equipment. The second one require antenna and power supply. If it is mobile the power is taken from the vehicle.
Headsets with automatic (called VOX-voice operated transmitter)transmission are available and can be mounted inside the Helmet. If you can restrict the range to 2-5 kilometers in average terrain, communication without break will be possible and in the Ghat sections the advantage of height difference can be utilized by proper planing. In many places the group of Ham operators collectively put up Repeaters for the use of licensed operators to enhance the coverage. Then 200-400kms are possible according to the height of the Repeater antenna.
As per rule, which is yet to be amended, mobile operation requires special permission, which is normally issued for 90days..
Last edited by stanproc : 06-04-08 at 05:26 PM.
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