Radio model considerations
• 0.5 to 1-Watt power. Usually claimed to have 5km transmission range.
• 1 to 2-Watt power. Usually claimed to have 8km transmission range.
• 2 to 3-Watt power. Usually claimed to have 12km transmission range.
• Over 3-Watt power. Usually claimed to have very long range.
Yeah, right... in the middle of the Gibson Desert at midnight, perhaps.
In the real world hills, trees, buildings, vehicles... even your own body reduce transmission range. The 0.5W ‘toy’ radios are cheap but limited to much less than 1km REAL transmission range – usually only a few hundred meters. The 1-2W units are good for road use with about 2km actual range, 3W units range out to about 4km on average, and 5W units reach out to more than 5 or 6 klicks. Y’ gets what y’ pays for, though. Up until recently, 2W radios were about twice the price of 0.5W units, 3W units about 3 times, and 5W units about 4 times. That’s all changing now. 5-Watt radios from China are available online, and cost less than AU$100... about the same as the ‘toy’ radios! So the price difference between short- and long-range models is becoming less important.
The main problem is the small aerial on hand-held radios – they aren’t very efficient, and the antenna is a bigger influence on transmission range than the power of the radio. Radios of lower power... 0.5-Watt up to about 2-Watt, all have fixed antennas, usually stubby little eighth- or quarter-wave ones. Taller half-wave antennas ( about 20cm high ) increase range, but you can’t use one if the radio has a fixed antenna. Detachable antennas, which are commonly fitted to radios of 3-Watt power or more, are much better. You can either attach a larger one for better range or use an external full-wave antenna for maximum range, and quite cheaply, too ( less than $50 ).
- Adding an external antenna is the most effective way to ensure optimum performance on a bike or scooter. Or you could add a right-angle antenna adapter so that the radio can lie on its side / back but still have the antenna vertical... fit it into a top-box, glovebox or under-seat compartment this way.
- For convoy riding, it is sensible for the leader and the sweep rider to use fairly powerful radios. Riders in the middle of the convoy can get away with lower powered units.
- Rechargeable batteries, once charged up, last several hours – enough for a full day of riding, provided your radio traffic is not constant. Also, remember that the high-power radios chew through batteries faster!
- Don’t hog the airwaves, please! While you are transmitting, nobody else can use the chosen channel, and everyone’s radio is using battery power to receive you. Forget singing or long, witty commentaries on traffic and road conditions! Keep your transmissions short and to the point. Speak s-l-o-w-l-y and clearly and, if possible, don’t use VOX ( voice-operated transmission ).
- For riding without a comms unit, always mount the radio as high as possible and make sure that the antenna is as vertical as possible. The aerial is the weak point of all hand-held radios and all transmissions eminate from the tip of the antenna in a flat >•< shape, so leaning the radio results in transmissions beaming either up or down ( very few bikers to hear you in the sky or underground! ). Attaching the radio to the inside of the windscreen, or inside a plastic top-box is good, so that it is away from electrical fields near the engine, and metal parts of your bike don’t restrict transmission much. Some riders prefer to attach the radio to their jacket, near the shoulder. Nice and high, quite effective, but it usually means an extra cable in addition to the one connecting the headset in the helmet, which quickly becomes an irritation.
- Important UHF Regulatory change: For decades, all small “Citizen Band” radios have had 40 channels, although in June 2011 the Australian standard changed to 80 channels, but with only 12.5KHz spacing between channels instead of the previous 25KHz spacing... so the same frequency band-width, but with double the number of channels squeezed into it. If buying a new radio make sure that this 12.5KHz channel-spacing is available – manually-programmable radios can be reset but pre-set ones cannot. Many popular retail brands have pre-set channels, so will never allow access to the extra 40 channels. Radios that have programmable channel frequencies usually ALSO have a programmable channel spacing that determines the “steps” between frequencies.
- Duplex operation was one of the major drivers behind the 40- to 80-channel switch. Duplex can be simulated by broadcasting on one channel but receiving on another. But there are so many different brands of radio, each with their own ‘version’ of Duplex, that setting up a large group such as a bike touring group to use Duplex is usually just too hard.
- goSpyder riders usually use Channel 19 for communication... this ‘general-purpose’ Simplex channel is rarely used outside urban areas so interruptions from other users are minimal. Other groups may use different channels.
UHF 80-channel: The base frequency for channel 19 remains unchanged, while the new channel frequencies #41-80 are interleaved between the old 40 channels – in ascending frequency, the channels now number 1, 41, 2, 42, 3, 43... etc.