Why sites kill radios
A construction site is the most hostile place a handheld radio ever works. Physically: two-metre drops onto rebar and concrete, brick dust that packs into every seam, rain for weeks, and gloved hands that can't work a fiddly keypad. Electrically: poured concrete floors, steel framing and scaffold sheeting that swallow radio signal, in exactly the way an open campsite doesn't — which is why the number on the box means nothing here. And operationally: the traffic is lifting plans, plant movements, exclusion zones and first-aid calls. A radio that garbles a banksman's "stop" next to a breaker isn't a cheap radio, it's a near miss. Every spec on this page follows from those three facts.
Why licensed UHF is the default
| Route | Fits | Licence | Watch out for |
|---|---|---|---|
| Licence-free (PMR446) | Small, open, short-lived jobs only — groundworks in a field, a compact refurb | None | 0.5 W won't hold through concrete; 16 shared public channels — the next trade along may be on yours |
| Licensed UHF | The default for working sites: multi-storey, steel-framed, plant on the move | Ofcom, ~£75 / 5 yrs (Simple UK Light) | Handsets need programming by a supplier; budget for accessories, not just radios |
| Network (PoC) radio | Multi-site contractors; sites plus vans plus head office on one system | None (uses mobile networks) | Per-radio SIM cost; depends on mobile coverage — basements and new cores can be dead zones |
Two reasons licensed UHF wins on site. Power and frequency: a licensed handset transmits at 4–5 W against PMR446's fixed 0.5 W, and UHF wavelengths thread through floors and steelwork better than anything licence-free can manage — the difference between "works everywhere on site" and "works until you go inside." Private channels: PMR446's sixteen channels are shared with everyone, and on a multi-contractor site or an urban plot that means other people's traffic in your lifting operations. The full trade-off lives in our licensed vs licence-free guide; contractors running crews across many sites and vehicles should read the network-radio comparison instead, because no conventional radio joins sites together.
The spec that survives
Sealing: IP66 the floor
IP66 keeps out dust entirely and shrugs off driven rain; IP67 adds survival of a dunk in a flooded trench. Anything lower fails slowly — dust in the PTT switch and speaker is the classic death, and it starts weeks before the radio actually dies.
Drops: MIL-STD, not luck
Look for MIL-STD-810 drop and vibration compliance. Site radios live on hi-vis clips two metres up and land on concrete, repeatedly. A chassis rated for it lasts years; a consumer shell lasts until the first scaffold lift.
Audio that beats plant
Noise-cancelling microphones and a genuinely loud, clear speaker — digital (DMR) handsets hold intelligibility in noise noticeably better than analogue. Pair every working handset with a remote speaker mic clipped at the collar, so nobody unhooks a radio one-handed on a ladder.
Gloves: fewer buttons, not more
The right site handset is the non-keypad variant: a big PTT, a chunky volume/channel knob, an emergency button — all operable in riggers' gloves without looking. Screens and menu keys are for the office, and on site they're just places for dust to get in.
Battery discipline
A shift is 10–12 hours with overtime, so specify high-capacity batteries and — this is the part sites skip — six-way multi-chargers in the site office with a named person racking radios at day's end. Most "broken radio" reports on any site are flat or abused batteries.
High-rise, and when a repeater enters
Handheld-to-handheld radio is line-of-sight, and a rising concrete frame removes the line of sight floor by floor. The practical pattern: a 4–5 W UHF handset holds a typical site to around six to ten storeys of poured concrete, depending on rebar density and how much of the talking happens in the core. Beyond that — or the moment the gatehouse can't reach the top lift reliably — the answer is a repeater: a fixed base unit, sited high on the structure and moved up as the building grows, that receives every transmission and re-broadcasts it at full power to the whole site. One repeater typically restores solid coverage to a tall single building; it also roughly doubles the system's working radius at ground level. It is supplier-installed kit on licensed frequencies, which is one more reason PMR446 has no answer for high-rise: you can't put a repeater on it. If the real problem is several sites rather than one tall one, stop before buying a repeater and read the network-radio guide — that's the tool for geography.
Fleet planning by gang
Radios per site is a role question, not a headcount question. The working rule: one radio per gang leader per trade — groundworks, steel, brickwork, M&E — plus every banksman and crane or plant operator (non-negotiable, and lifting traffic gets its own channel), the site manager and foremen, the gatehouse, and first aiders. That lands a mid-size site at 10–25 handsets and a major project at 50-plus, at which point you split channels: lifting operations on one, site logistics and deliveries on another, management on a third. The discipline that makes it work is the same one on every well-run site: the lifting channel carries lifting traffic and nothing else. Add ten per cent spares on charge, and expect to lose a couple a year to attrition — a fleet plan that can't absorb a lost radio isn't a plan.
Hire or buy
Both are normal in UK construction, and the honest crossover is simple: hire for the project, buy for the business. Hire fleets come programmed, licensed under the hire company's arrangements, insured against loss and swapped when damaged — ideal for a 12-week job or a one-off high-rise where you'd never own a repeater. But hire pricing typically overtakes the purchase price somewhere between 12 and 18 months, so a main contractor or trade firm with continuous site work is throwing money away by month 18. If you'll have radios on some site every month from now on, buy a core fleet on your own £75 five-year licence and hire the peaks and the repeaters on top.
Quick answers
Do we need a licence?
In practice, yes for any working site: licence-free PMR446 is legal but rarely holds through concrete and steel, and its channels are shared with everyone nearby. An Ofcom Simple UK Light licence is about £75 for five years and covers the whole business.
Best spec for high-rise?
Licensed UHF at 4–5 W as the floor; above roughly eight to ten storeys of poured concrete, add a repeater sited high on the structure and moved up as the frame rises.
How many radios per site?
One per gang leader per trade, plus banksmen, plant and crane operators, site management, gatehouse and first aiders — typically 10–25 on a mid-size site, 50+ on a major project, plus ten per cent spares on charge.
Will they survive rain and dust?
Only radios built for it: IP66 sealing as the floor (IP67 for immersion) and a MIL-STD-810 drop rating. Consumer twin-packs carry neither and die in weeks on a working site.