I currently use European PMR - Private Mobile Radio, (called FRS-Family Radio Service in the US). This is fine for the short distance bike to bike and bike to car comms. that I have used it for, but due to the high operating frequencies (446-467MHz) and low power, only works reliably when you can see the other vehicle (no terrain blocking the line of sight) and then only up to 2-3k.

It has it's plus points; cheap ($80/GBP50 per person), widely available, legal (in many developed countries), compact, standard batteries & I guess hard to detect where used illegally, due to the low power.

My current set-up is as follows:
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Cobra PMR ($30/GB20), due to the standard headset connection, keylock function & price. (NB the MT700 model has pillion intercom facility too).

Bike headset ($25/GB15) with bar-mount talk button
http://www.maplin.co.uk/Products/Mod...eNo=27212&MR=N

Koss 'The Plug' earphones $25/GB15, as when riding at speed, or with earplugs, the standard speaker in the bike headset is inaudible.
http://www.fixup.net/tips/earbud/30d...d_earphone.htm
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However, it would be useful to have a radio with a range of at least 20k, to allow a different pace/itinerary between vehicles and for rider to base camp comms- NB I'm not talking about places with mobile phone coverage.

Does anyone have experience of a radio system that will achieve 20k or more, where at least one of the 2 radios must be hand-portable for use on a bike? (I could probably live with a bit less between bikes & can put a 'full size' radio in the 4x4) Will CB do this? What about marine VHF?

Any ideas or experience would be appreciated.

Thanks,

Ian

Okay!

I use comms a huge amount on my expeds, so both Land Rovers have HF, VHF, VHF airband and UHF (as well as satphone).

Generally we go with the two 4wds, and up to 9 'bikes.

In short, VHF will give you line of sight 1km per watt (safe planning) - your PMR are limited by law to 0.5W (ideal conditions will give you up to 2km or so)

UHF (what you have) gives you less range, but supposedly more 'punch' through buildings etc. Not much advantage in the desert!

HF (used NVIS) will give you almost guaranteed coverage out to 150-200 km, but is MUCH more expensive, bulky and requires a higher level of competence than the other options.

Key to all systems is your antenna - for useable 20km range, you are going to need a 1+m whip (regardless of frequency) - that's it.

Once you have accepted that, options:

Cheapest: VHF 'mobile' rig, VHF 50W running off bike battery.
Smallest: VHF handheld, run into 50W amp, running off bike battery - gives you option to use handheld only whilst close.

When the bikes set off, they have handhelds each, and within the group they have one VHF amp(100W - hey, why not!), telescopic (not suitable on the move) antenna and a HF Manpack for emergencies).

Feel free to email if you have further questions.

One last thing, import/use of all these options (once you pass 0.5W) requires a licence in nearly every country of the world.

Sam.

Look at this article: ICOM IC-M87
Small marine VHF/PMR446 totaly waterproof 12V or battery autonomy 20 hours price actually expensive +- 500€

Philippe (Brussels)