Why Your Radios Don’t Work Where You Need Them To
RF propagation, real-world coverage gaps, and how to actually fix them

Anyone who’s spent time in the field with two-way radios knows the frustration. You key up, nothing comes back. You walk twenty feet around the corner of a building and suddenly you’re talking clear as day. You drive into a valley and it’s like the network doesn’t exist. You’re not imagining it. RF propagation is genuinely unforgiving, and the environment your team operates in is almost always working against you.

Here’s what’s actually happening, and what you can do about it…

The Physics A lot of Radio Integrators Fail to Explain at the Point of Sale

Radio waves travel in straight lines. That sounds simple until you realize the world is made of things that aren’t straight lines: hills, ridgelines, dense stands of Douglas fir, concrete parkades, steel-frame warehouses… Every one of these obstacles either absorbs, reflects, or diffracts your signal.

Terrain is the biggest culprit in Western Canada. You could have a repeater site sitting on top of a mountain, and a crew working in the valley below it might as well be in a different province. RF doesn’t bend around ridgelines, it diffracts slightly at the edges. That diffraction zone is limited and lossy. If your repeater can’t achieve line-of-sight to the work area, you’re going to have dead zones. Full stop.

Vegetation is underestimated by almost everyone who hasn’t done a proper path study. A dry open field and a mature forest are not the same RF environment. Wet foliage in particular (think coastal BC in October) absorbs VHF and UHF energy significantly. The higher your frequency, the worse it gets. A dense forest canopy can introduce 10–20 dB of additional path loss that your link budget never accounted for.

Buildings introduce a different problem: multipath. Signals bounce off glass curtain walls, metal cladding, and concrete structures and arrive at your radio slightly out of phase with each other. In analog systems, this sounds like flutter and distortion. In digital systems, it can cause the signal to drop out entirely even when your radio is showing signal bars. This is why indoor coverage in commercial and industrial buildings almost always underperforms what the outdoor coverage map predicts.

The Scenarios We See Most Often

Mining and resource extraction sites. Pit walls, haul road geometry, and underground portals create predictable dead zones. A crew at the bottom of an open pit is surrounded by terrain that reflects some signal and blocks the rest. Underground is its own discipline entirely.

Construction sites. A greenfield site in Phase 1 looks nothing like the same site when structural steel goes up in Phase 3. Coverage that worked during groundbreaking won’t work when you’ve got six floors of rebar and concrete surrounding your users.

Municipalities and public safety. Urban canyons between mid-rise and high-rise buildings create consistent coverage shadows. A patrol unit that’s clear on Main Street can drop coverage entirely in a service alley two blocks away.

Industrial facilities. Process plants, tank farms, and heavy manufacturing environments are among the worst RF environments in existence. Metal structures scatter and absorb signal simultaneously. Noise floors inside facilities are often elevated by machinery interference.

What You Can Do About It

First: don’t assume. A coverage map generated without a site survey and path study is fiction. Before you deploy or expand a system, get a propagation analysis done against actual terrain data. Tools exist, but they need accurate antenna heights, real terrain files (SRTM data or better), and clutter models that account for vegetation and building density. If your vendor hands you a coverage map that looks like a perfect circle, ask how they generated it.

Repeater placement is everything. The goal is elevation and unobstructed line-of-sight to the largest possible percentage of your coverage area. In hilly terrain, this sometimes means multiple repeater sites with linked infrastructure rather than one high-powered site trying to cover everything. Motorola Solutions builds their MOTOTRBO repeater portfolio around exactly this kind of scalable, linked architecture.

In-building coverage needs its own solution. Distributed Antenna Systems (DAS) and passive DAS with bi-directional amplifiers exist precisely because the building envelope defeats outdoor coverage. If your team operates in a facility where reliable communication is safety-critical (and in most industrial environments, it is) treating in-building coverage as a separate design problem is not optional. Westcan ACS works with Comba to ensure in-building coverage is reliable for first responders in the event of emergencies.

Tait Communications has built a strong reputation in critical infrastructure sectors for exactly this reason. Their mobile and portable radios are engineered for demanding RF environments, and Tait’s approach to network design acknowledges that coverage is a system problem, not a device problem. Their trunking infrastructure gives system designers the tools to manage coverage across complex, multi-site environments with the kind of redundancy that critical operations require.

Antenna selection matters more than most people realize. A radio is only as good as the antenna connected to it. In high-multipath environments, antenna diversity helps. In fixed infrastructure, gain and pattern selection can mean the difference between a site that covers 80% of your operational area and one that covers 60%. This applies to both mobile vehicle antennas and portable antenna selection for body-worn devices.

Power is not the answer. This is probably the most common misconception in the industry. More wattage doesn’t necessarily solve a terrain obstruction problem – it increases your coverage radius in open space but does almost nothing for a crew working in a valley or inside a steel building. If you’re bumping power trying to solve a coverage problem, you’re treating a symptom.

When It’s Time to Reassess

If your team is reporting dead zones, if supervisors are relying on cell phones as a workaround, or if near-miss incidents have involved a communication failure, it’s time for a formal RF assessment, not an incremental tweak.

The combination of proper repeater infrastructure, site-linked architecture, and purpose-built hardware from manufacturers like Motorola Solutions and Tait Communications can solve most coverage problems. But it has to be designed against the actual environment your people work in, not the ideal environment on a spec sheet.

RF propagation is physics. The terrain, the trees, and the buildings aren’t going to change, but your system design can. Reach out to your Westcan ACS representative for more information on how we can keep you connected in Western Canada’s diverse landscapes.