What each technology actually sees

A Remote ID (RID) receiver listens to the radio broadcast that most drones sold since 2023 must transmit by law under FAA Part 89, EU Delegated Regulation 2019/945 and equivalent rules: a serial number, position, altitude, velocity — and, the part that matters to investigators, the location of the pilot at take-off. A receiver turns that broadcast into a logged, timestamped record. It hears nothing from an aircraft that does not broadcast.

An RF-spectrum detector scans the airwaves themselves. It can spot the video downlink or control link of any transmitting drone — including FPV rigs and modified aircraft that stay silent on RID. The trade-off is identity. Depending on the protocol, it may decode the drone model; often it can only tell you that something transmitting is out there, in a band shared with Wi-Fi, Bluetooth and everything else in a busy RF environment. False alarms are the operational cost you accept for that wider view.

Radar bounces a signal off the airframe. It measures position and movement precisely, works against aircraft with no emissions at all, and covers large areas from one installation. It cannot tell you who is flying, it is the most expensive option by a wide margin, and siting, processing and regulatory review make it a facility-scale project rather than a purchase.

The question that decides everything

Before comparing products, answer one question honestly: what does your site actually face? A correctional facility dealing with organised contraband drops faces compliant consumer drones flown at night from public land — RID sees those. A site concerned about a skilled FPV operator filming a fenced compound faces aircraft that may never broadcast — RID alone will not see those, and no honest vendor will tell you otherwise. Most sites we review face the first threat but budget as if they face the second, or the reverse.

There is also a legal dimension that surprises buyers: counter-drone measures — jamming, spoofing, taking an aircraft down — are illegal for private operators in most jurisdictions, including around critical infrastructure in many cases. Detection is what you are buying. Everything on this site assumes that boundary.

Four questions that decide it

1. Does your threat broadcast RID? Consumer and commercial aircraft from the major brands generally do, because the law requires it. Home-built FPV rigs generally do not. If you do not know, an RF-spectrum survey answers it faster than a datasheet.
2. Do you need the pilot’s location, or just the alert? If evidence matters — prosecution, internal investigation, regulator follow-up — RID is the only low-cost layer that provides it.
3. What is the perimeter? A single building may be covered by one portable receiver. Kilometres of fence line multiply nodes — and make radar’s per-site economics look different.
4. What happens after detection? If the answer is “call security”, presence-only alerting may be enough. If the answer is “prosecute”, you need RID logs with timestamps.

What RID cannot do

Say it plainly: an RID receiver cannot see an aircraft that does not broadcast, and no detection technology can stop an aircraft in flight. Jamming and take-down measures are illegal for private operators in most jurisdictions our clients work in. Detection is about knowing what is overhead and being able to act on the ground — not about knocking anything out of the sky.

Method and limitations

Budget figures are vendor-reported list-price ranges checked September 2026. Our own field validation of detection distances is in progress; until we publish it as measured data, treat every range claim — ours included — as a claim. The comparison table above is regenerated whenever we re-check a figure, and the candidate version lives on the Receivers page with per-row sources.