Friday 16 September 2011

446 Mhz hand held walkie-talkies

Have you seen the small 446 Mhz hand held (licence free) walkie-talkies that are available. We use a pair when locking the boat. They are good for the lock wheeler to keep in touch with the helmsman, They are low power and have a range of half a mile or so. We have a pair of Motorola that take 3 AA rechargeable batteries. A set of batteries lasts a full day and we re-charge them overnight.

This started me thinking that it would be good to have a boaters channel on 446 Mhz that we would all use. This would be good for keeping a watching brief for other boats on the move that might like to buddy up through the locks.

We use Channel 1 sub-channel 11 when working through locks and so I suggest that other boaters could use that channel for short range communication boat to boat.

We use the same radios when we are out on our motorcycles using channel 8 sub channel 15. This is the popular bikers channel and it is surprising how often we would hear someone bike to bike.

Private Mobile Radio is a part of the UHF radio frequency range that is open without licensing for personal usage in most countries of the European Union. Depending on surrounding terrain range can vary from a few hundred metres (in a city) to a few kilometres (flat countryside). The United Kingdom introduced PMR446 service in April 1999.

The range of 446 Mhz, just like any VHF or UHF radio, is dependent on many factors like environment (in-city range is far less than in an open field), height above surrounding obstructions and to a lesser extent, weather conditions. The antenna type and location, transmit power and receive sensitivity also affect range. However with PMR446 most of these variables are fixed at manufacturing to comply with the PMR446 specifications.
Frequency (MHz)
The sub channel number is a sub-audiable tone that is transmitted at the same time as you speak. If your radio is set to channel 1 but on any other than  sub-audiable tone 11 the radio will ignore the transmission and not turn on the receiver. This makes the radio ignore unwanted transmissions on the same channel from non boaters.

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