PMR 446 MHz radio's
In response to the request from Tiberius
PMR 446 MHz 2 way radio.
A licence free short range communication service. Built to an internationally agreed industry standard, Any PMR 446 radio, irrespective of manufacturer, will work with any other PMR 446 radio.
The radio's have 8 primary channels and both users radio's must be set on the same channel. Each of the 8 channels can be sub divided into 38 "private" (secondary) channels using Continous Tone Coded Squelch System ( CTCSS ). When both or more radio's are set on identical primary and secondary channels, they can be locked to prevent accidental changes when fumbling with the volume control.
We should read "private" in the loosest possible way. It's not a digital system, any other users whose radio's are set on the same combination, and within range, will be able to hear your conversation and may even join in, wanted or not!.
About the range.
In a very heavily built up area, like a town centre, the range can be measured in 100's of yards. We may experience "drop-outs" here. This is a result of a radio receiving an out -of- phase signal "bounced" of a nearby building, this cancels out the "direct" signal resulting in a bitty conversation. This is more pronounced when both radio's are moving. When used in open countryside then 2 - 4 miles is possible. FM signals in the UHF band in which these radio's operate are "line of sight". In a hilly landscape the range will be reduced and, by the same token, flat areas will give the best range.
And, OUT of range.
Some, but not all radio's have an "out of range" function. When enabled, the radio's will frequently "ping" each other. Based on the signal strength of the returned ping, the radio's may sound an audible alert indicating impending loss of contact. At this point the lead rider needs to ease off a bit, and the tail end charlie needs to get a move on in order to close the range. There are a great many functions not covered here, but will be in the manual that comes with the radio.
Let's have a look at hands free headsets.
Most radio's have a VOX (voice activated switch) facility which can be enabled. Used in conjunction with a headset, this is a useful way of communicating with fellow riders. Some headsets have a lapel mounted microphone and an "in your ear" earpiece. In use, this is NOT the best type for bikers. For a kick off, the earpiece renders the user deaf on that side. The lapel mounted microphone picks up a lot of wind noise, making it very difficult to set the VOX sensitivity threshold. My preferred radio's are Uniden PMR 885/2. (The latest type is 887). The headset provided is a combined earspeaker and boom mic, the speaker held in place by a clip which passes around the back of the ear ( like the police use). As the mic is so close to the mouth, it is much easier to set the level at which the VOX will respond to a voice.
Abuse!.
I'm afraid, that sooner or later, misuse of the sytem will be experienced. In no way is it a private system. Every Tom, Dick and wannabe Lord HawHaw will get hold of a radio and inflict foul mouthed abuse on all and sundry. Many radio's have a scanner function. Earwiggers will set their radio's to scan all the channels (including CTCSS privates). when their radio detects an active channel, YOUR channel, it will lock onto that channel, and you then have "company". We quickly learned the golden rule on CB (Citizens Band) radio. NEVER, EVER, RESPOND TO ABUSE. It's exactly what they want you to do. Simply ignore them and they will soon get fed up. If they persist, then don't let them spoil your ride, Switch the radio's off and holler at each other.
Busy times!
Christmas, Many thousands of radio's are presented to children at this time of year. For several days after, the channels will be crowded with giggling youngsters, but the novelty soon wears off and peace returns. School summer holidays will bring parents keeping tabs on their flock during outings. Activity groups use them instead of the pay to use service further up the band. In my local area, we still have a large warehouse directing forklift trucks around using this service.
The last time I used a pair of radio's was, when perched 30 feet up a ladder, trying to aim a television antenna at an invisible transmitter 60 miles away. A friend with the other radio down in the dining room informed me when a signal lock was aquired, Easy!
Hope this is of help
Regards
Bob
