What's so special about these presentations? Yes - a cellular/trunked model will enable greater use of spectrum. This has been well known for the last twenty years. Yes - spread spectrum/ultra-wide band allows re-use of the same spectrum. BUT the price you pay (for cellular or spread spectrum) is gradual degradation of service with increased users. Yes - radio waves do "pass through one another" allowing spectrum re-use, and that's been known since beam antennas came into use in 1919.
These presentations are simply examples of special pleading by commercial interests. Some corporations believe that the law of gravity could be repealed if they lobby hard enough. Everyone wants a chunk of the radio spectrum and non-one wants to pay for it or show responsibility to other users.
Red-light cameras and speed cameras have been in Australia for years now and they've generated a new way to express your opinion of the state police.
Get a few mates onto the back seat of your car, cover the number plate, then get your mates on the back seat to moon through the rear window while you drive through a red light! Great fun!
In Australia and the European Community a fair slice of the 70cm band (420 to 450 MHz) has already been taken.
The Australian Communications Authority has ruled that a segment of the band (433.05-434.79Hz) is given over to Low interference Potential Devices (LIPDs)(called Low Power Devices in the EC). These may use any modulation method at a power of 25mW. http://www.aca.gov.au/legal/licence/class/lipd.rtf
25mW may not sound like much, but the main users of these LIPDs - crane remote controls - cause a geat deal of interference to repeaters. There are an increasing number of devices using this band including car alarm remotes and stereo headphones.
At least the operators of cranes understand the problem and will change frequencies, but the general public don't understand and don't know how to avoid causing interference.
In theory LIPD users have no protection against interference, but in practice the ACA will not assist radio amateurs, even when they can demonstrate a public service need.
The same situation occurs in Europe. US hams - fight this one if you can! The political environment has changed. Corporations have more clout than volunteer organisations.
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What's so special about these presentations?
Yes - a cellular/trunked model will enable greater use of spectrum. This has been well known for the last twenty years.
Yes - spread spectrum/ultra-wide band allows re-use of the same spectrum.
BUT the price you pay (for cellular or spread spectrum) is gradual degradation of service with increased users.
Yes - radio waves do "pass through one another" allowing spectrum re-use, and that's been known since beam antennas came into use in 1919.
These presentations are simply examples of special pleading by commercial interests. Some corporations believe that the law of gravity could be repealed if they lobby hard enough. Everyone wants a chunk of the radio spectrum and non-one wants to pay for it or show responsibility to other users.
Red-light cameras and speed cameras have been in Australia for years now and they've generated a new way to express your opinion of the state police.
Get a few mates onto the back seat of your car, cover the number plate, then get your mates on the back seat to moon through the rear window while you drive through a red light! Great fun!
Yeah but...
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In Australia and the European Community a fair slice of the 70cm band (420 to 450 MHz) has already been taken.
The Australian Communications Authority has ruled that a segment of the band (433.05-434.79Hz) is given over to Low interference Potential Devices (LIPDs)(called Low Power Devices in the EC). These may use any modulation method at a power of 25mW. http://www.aca.gov.au/legal/licence/class/lipd.rt
25mW may not sound like much, but the main users of these LIPDs - crane remote controls - cause a geat deal of interference to repeaters. There are an increasing number of devices using this band including car alarm remotes and stereo headphones.
At least the operators of cranes understand the problem and will change frequencies, but the general public don't understand and don't know how to avoid causing interference.
In theory LIPD users have no protection against interference, but in practice the ACA will not assist radio amateurs, even when they can demonstrate a public service need.
The same situation occurs in Europe. US hams - fight this one if you can! The political environment has changed. Corporations have more clout than volunteer organisations.