Radio Basics: Why the Number on the Box Is Wrong

On the box: "range up to 10 km". On your street: four hundred metres, if that.

It isn't quite a lie — it's a measurement taken in the most favourable conditions imaginable, peak to peak, without a single obstacle. What the manufacturer doesn't say is that those conditions exist nowhere near where you live.

Understanding why is the highest-return skill in the whole radio field. It costs nothing, it explains 90% of the disappointments, and it will stop you buying the wrong gear three times over. This article covers the physics in plain language, the three legal options in Europe, and operating discipline — which in practice is where almost everyone fails.

Why range is what it is

The line-of-sight rule

At the frequencies used by handheld radios — VHF around 145 MHz, UHF around 446 MHz — waves travel essentially in a straight line. They don't follow the curvature of the Earth, don't bend around a hill, and pass poorly through buildings.

The practical rule fits in one sentence: if you can see the place, you can probably talk to it. Otherwise it's uncertain.

Hence the real range table, which bears no relation to the packaging:

Situation	Realistic range
Dense city, two streets separated by buildings	300 to 800 m
Open urban area, boulevard, park	1 to 3 km
From an upper floor down to the street	1 to 3 km
Open countryside, line of sight	5 to 10 km
Peak to peak, no obstacles	tens of kilometres

The number on the box corresponds to the last row. Your use corresponds to the first.

Height before power

This is the point everyone gets backwards. Faced with a poor link, the reflex is to buy something more powerful. That's almost always the wrong lever.

Doubling transmit power gains a few percent of range. Gaining a few metres of height can double it. Stepping outside a building, going up one floor, moving away from a concrete wall: these free actions do more than any pricier radio.

Practical corollary: if you have to call from a flat, go to the window or the balcony. If you're in a car, stop and get out.

Antenna before the radio itself

After height comes the antenna — and only far behind that, the radio. It's the same conclusion as in our Baofeng UV-5R analysis: the stock antenna is the real bottleneck.

Remember: power, height, antenna — in the reverse order of what the shop suggests.

The three legal options in Europe

PMR446: no licence, right now

This is the default solution for family use. UHF band from 446.0 to 446.2 MHz, 16 analogue channels, 500 mW maximum power, a mandatory integrated, non-removable antenna, and no licence or declaration in most EU countries.

What to know before buying:

All PMR446 devices are interoperable, whatever the brand. You can mix models.
Repeaters and fixed stations are prohibited. Use is mobile, handset to handset.
No encryption is possible or permitted. The CTCSS codes these radios offer encrypt nothing: they merely filter what you hear. Anyone on the same channel hears you.
A non-type-approved radio programmed on 446 MHz remains illegal, even at low power — which covers the handhelds with removable antennas we've discussed before.

For a household: one radio per self-sufficient adult, plus a spare.

CB: more range at ground level, bulkier

The citizens' band, around 27 MHz, remains licence-free in most European countries, with higher power and 40 channels. Its physics differ: at that frequency, waves follow terrain slightly better, giving more consistent links at ground level.

The trade-off: far longer antennas, bulkier equipment, essentially vehicle-based use. It's the right choice if your need is road or rural rather than pedestrian and urban.

The amateur licence: the only route to everything else

Amateur bands give access to more power, antennas of your choice, repeaters, and ranges in a different league. They require an operator's certificate obtained by examination from the national regulator.

It isn't just an authorisation: it's the best existing training in degraded communications, and the community that comes with it. If radio interests you beyond family backup, that's the path.

Discipline: where everyone fails

The gear is almost never the problem. The procedure is.

The basic action

A handheld radio is half-duplex: you either talk or listen, never both. Three universal beginner errors:

Speaking as you press. Press, count one second, then speak — otherwise the start of your sentence is cut off.
Not releasing. While you hold the button you hear nothing and you block the channel for everyone.
Speaking too close, too loud. Five centimetres away, at a normal volume. Shouting saturates and becomes unintelligible.

The structure of a message

The standard order: recipient, then sender, then message. "Dad from Lea, I'm at school, over." The recipient first, because they need to know it concerns them before listening to the rest.

Three words are enough to structure an exchange: "over" when you hand back the floor, "received" to acknowledge, "out" at the end. Nothing military about it: it's simply what stops two people talking at once.

Three rules worth more than gear

Short. Long messages saturate the channel and are poorly understood. One idea per transmission.

Planned. Decide in advance on the channel, the listening windows and who calls whom. A radio left on constantly drains its battery; a scheduled watch — five minutes every hour, say — preserves runtime and guarantees someone is listening.

Spelled. For a name or a code, use the international alphabet: Alpha, Bravo, Charlie. It seems excessive until the day your correspondent confuses B and P through the noise.

And the reminder that applies everywhere: your channel isn't private. Whatever you say, anyone listening hears. Don't broadcast a precise address, sensitive information, or anything you wouldn't say aloud in the street.

The limits, and the classic mistake

What radio gives you: a link that works when the mobile network is saturated or down, with no carrier, no subscription, over a short but controlled distance.

What it doesn't give you: range through walls, confidentiality, or a guaranteed service. And it doesn't replace a plan: without agreed channels and listening times, two equipped people won't talk to each other.

The classic mistake is buying before testing. The right order is the reverse: borrow or buy the cheapest pair, measure the real range between your usual points — home, school, work — and then decide whether you need better. Nine times out of ten, two thirty-euro radios cover the actual need, and it's placement that changes everything.

The second mistake is thinking gear excuses you from practice. A family that has never run a test will discover on the day that nobody knows which channel to use.

Where to actually start

A pair of PMR446 radios to begin with. No licence, immediately usable, interoperable with everything else.
Measure your real range between your usual locations, and write it down. That's exactly what the "range tested" column of our radio memo sheet is for.
Set a family channel and listening times, and write them into your household emergency plan.
Run a real test: two people, two known points, a complete message. Twenty minutes.
Recharge and check every three months, alongside the rest of your equipment.
If radio genuinely interests you, look into the operator's certificate. That's where the subject begins.

Conclusion

Radio isn't complicated, but it obeys a physics that marketing hides. Once you've understood line of sight and the primacy of height over power, you stop buying at random and start getting results.

And the deciding factor still isn't the gear: it's having agreed on a channel, a time, and having tried once before you needed it.

Line of sight decides. Height before power. The plan before the radio.

Sources and further reading

Wikipedia (FR) — PMR446 (in French) — band, channel count, applicable CEPT decisions, interoperability and the ban on encryption.
F.O.R.S.F — PMR446 radios (in French) — technical characteristics (446.0-446.2 MHz, 500 mW ERP, fixed antenna), typical ranges and the case of non-approved devices.
Radio Collectif — PMR446 guide (in French) — 16 channels spaced 12.5 kHz apart, prohibition of repeaters and base stations, absence of confidentiality.
PMR guide for emergency communication (in French) — gap between advertised and observed urban ranges, sizing for a household.
Midland — PMR446 regulations (in French) — licence-free conditions of use in Europe and permitted equipment.
Wimo — PMR446 and licence-free bands (in French) — comparison with 27 MHz CB and amateur bands under national regulators.