Details
A microwave link is a directional radio connection between two fixed points, carrying capacity comparable to a cable without needing anyone to dig one.
Why it exists
Fibre is better when it is already there. It frequently is not — a repeater on a hilltop, a pumping station on a distribution network, a quarry, a construction site, a plant across a valley. Where trenching would cost more than the project or take longer than the schedule allows, a microwave hop is installed in days.
The second reason is independence. A link on your own equipment does not share a failure mode with a leased line, which is why critical sites often run both: fibre as the primary path and microwave as a diverse backup that no single excavator can sever.
What determines whether it works
Line of sight, with clearance. Not just visible from one end to the other — the ellipsoid around the direct path, the first Fresnel zone, must be clear of obstruction. A ridge or a treeline that merely touches the visual path can still remove most of the signal.
Path profile. Terrain between the endpoints is modelled from elevation data and then verified on site. Earth curvature and atmospheric refraction both bend the effective path and both belong in the calculation.
Fade margin. The link must operate with enough headroom to survive rain, atmospheric ducting and multipath. Required margin follows from the availability target and from local rainfall statistics.
Frequency band. Lower bands travel further and resist rain; higher bands carry more capacity over shorter hops. The choice follows the requirement, and it is also constrained by what BTK will assign on that path.
Availability, honestly specified
| Target | Downtime per year | Typical use |
|---|---|---|
| 99.9 % | ~8.8 hours | Office connectivity, non-critical data |
| 99.99 % | ~53 minutes | Corporate backbone, video |
| 99.999 % | ~5 minutes | Radio backhaul, SCADA, emergency systems |
Each additional nine costs real money in antenna size, tower loading and frequency planning. The right approach is to specify the number the traffic justifies rather than the highest number available.
Where TechnoRF uses them
What the work involves
Path survey and profile study, frequency planning and BTK coordination, structural assessment of the mounting point, antenna alignment, commissioning measurement against the predicted budget, and periodic re-alignment — because masts move, vegetation grows and buildings appear. See network installation or get in touch.
Frequently Asked Questions
How far can a microwave link reach?
It depends on frequency, antenna size and required availability far more than on the equipment. Lower bands around 6–11 GHz support tens of kilometres; higher bands around 18–38 GHz offer more capacity over shorter hops because rain attenuates them severely. The binding requirement is almost always clear line of sight with Fresnel zone clearance, not raw distance.
What does 99.999 per cent availability actually mean?
About five minutes of outage per year, against roughly nine hours at 99.9 per cent. The difference is paid for in antenna size, fade margin and frequency choice — and the specification should come from what the link carries. A backhaul serving emergency communications and a link serving an office deserve different numbers, and quoting five nines everywhere just raises cost.
Do we need a licence for a microwave link?
For licensed bands, yes — BTK coordinates frequency and path to prevent interference, and the assignment is specific to that path. Licence-exempt bands avoid the application but offer no protection from interference, which makes them acceptable for non-critical traffic and unwise for anything a critical system depends on.
Why did a link that worked in summer fail in winter?
Usually one of three causes. Rain fade, if the link runs in a high band with insufficient margin. Vegetation, because trees that were bare during the survey now intrude into the Fresnel zone. Or multipath from a reflective surface — water, a flat roof, wet ground — that behaves differently with conditions. All three are avoidable at design time and expensive to fix afterwards.