Bluetooth tracker in an open field: range after dark

How far does a Bluetooth tracker reach in an open field?

The rated figure is 60 m with a clear line between the phone and the tag. That is the best case: no walls, no crowd, no metal. In a field it is usually the nearest thing to that case you will get, which is why open ground is the standard place to test a tag.

Treat 60 m as a ceiling and 20 to 40 m as a sensible expectation once other people are standing between you and the tag. Those lower numbers are a rule of thumb, not a measured result.

What shortens the range outdoors?

Bluetooth tags use the 2.4 GHz band, and that band is absorbed by water. People and wet things are mostly water.

• Bodies. A crowd between you and the tag cuts the signal, and your own body does too if the tag is behind you.
• Wet clothing and grass. Damp coats absorb more than dry ones.
• Metal. A van, a gate or a barrier reflects and blocks.
• Height. A tag on the ground reaches less far than one on a fence rail.

Does darkness change anything?

Not the radio. Bluetooth does not care whether it is day or night. What changes is you: in the dark you cannot see the obvious place a coat landed, so you depend on the speaker. The BlueTag speaker is rated at 80 to 100 dB, but sound in an open field has nothing to bounce off and dies away quickly, so you usually need to be well inside the radio range to hear it.

Can you test it in two minutes?

Yes, and you should do it once before relying on any tag.

1. Leave the tag on a fence post or a wall, at about waist height.
2. Walk away in a straight line with Find My open on your iPhone.
3. Ring the tag every ten paces and note where it stops answering.
4. Repeat with the tag inside a coat pocket and compare.

That second number is the one you should remember. It is your range with a coat around the tag.

Why is the first tag test often disappointing?

People tend to test a tag in the one place that flatters it: a living room, with the phone a metre away. The first outdoor test then feels like a letdown. Radios are measured in free space, and the real world adds absorption at every step. A tag in a coat pocket on a hook behind a crowd of people is nowhere near the lab figure.

That gap is normal rather than a fault. If the tag answers reliably at 15 to 20 m outdoors with a coat around it, it is behaving as a coin-cell Bluetooth beacon should. The useful thing about the walk test is that it replaces a vague worry with a number you can plan around.

What happens beyond Bluetooth range?

Past the point where your own phone loses the tag, the Find My network takes over. Other Apple devices hear the tag and report a position, which appears in the app with a time. In a field with few people this can be slow, so it is a safety net, not a guarantee.

How BlueTag helps

BlueTag is a Find My compatible tag for iPhone, MFi certified, with a CR2032 coin cell and IP67 ingress protection, which suits a wet field. It comes as a box of two, so one can sit in a coat and the other in a bag. Housing is 36.3 × 36.3 × 9 mm, and it has no Ultra Wideband radio, so there is no arrow to follow.

It will not work with Android, and it will not extend its range because you wish it would. Used with the test above, it tells you what to expect. See BlueTag or go to the checkout.

Frequently asked

How far does a Bluetooth tracker work outdoors?

Up to 60 m in a clear line of sight, which usually means open ground. With people, wet clothing or metal in the way, expect a lot less.

Does rain affect a Bluetooth tracker?

Rain does not stop the tag, which is rated IP67, but wet air and wet bodies absorb some of the 2.4 GHz signal. Range can fall a little in heavy rain.

Why can I not hear my tracker in a field?

Sound carries poorly in open space and a tag in a pocket muffles it further. Move closer, stand still and listen in several directions.

Can a Bluetooth tracker work without mobile signal?

The tag needs no signal. Your phone talks to it over Bluetooth, and a reported sighting from another Apple device needs that device to get online at some point.