Your 72-Hour Kit Is Missing One Thing: Reaching Family When There's No Signal

On March 26, 2025, the European Commission published its Preparedness Union strategy. It includes the advice that every household should keep enough essential supplies for at least 72 hours. The sample list includes food, water, a flashlight, a power bank, a radio, cash and medicine. Many countries have published their own guides, for example Finland.

The radio on the list is there for official announcements. It can't answer the questions many people worry about most during a power outage: is my child okay at school, how are my parents across town, and where will everyone meet?

Nelos is not affiliated with or endorsed by the EU. We mention the strategy because it is the reason many families in Europe are putting together a 72-hour kit.

How long does the mobile network last in a power outage?

Usually only a few hours. Cell sites run on backup batteries, and the batteries run out before grid power comes back. The blackout in Spain and Portugal on April 28, 2025 showed this clearly:

• Portugal was without power for nearly 10 hours. Its 4G/5G sites had backup batteries that last only 2 to 8 hours.
• Network traffic fell by about 90% in Portugal and 80% in Spain compared with normal. After a few hours, intermediate network nodes ran out of backup power and the network grew even weaker.
• WhatsApp and Telegram became useless. An editor at Xataka Android wrote that on that day it was impossible to know where loved ones were or whether they were okay.

The lesson: don't wait until the signal is gone to look for a way to communicate. Your backup has to be ready, installed and tested beforehand.

Ways to communicate with no signal

No single device does everything. The sensible approach is a combination: an FM radio for official news, plus a way to message within the family.

Walkie-talkies and LoRa complement each other: a walkie-talkie is fast when you need to talk right now, and LoRa keeps messages for whoever isn't holding their phone at that moment. See also LoRa mesh vs walkie-talkie and LoRa mesh vs satellite messenger.

What Nelos can do when there's no signal

Nelos turns a phone and a small LoRa radio into your family's own communication channel, with no cell tower, internet or server. The phone connects to the radio over Bluetooth; the radio sends messages and locations directly to other people's radios.

When the mobile network goes down, your family can still:

• Message as a group and one-to-one. Messages are saved, so someone who wasn't holding their phone at the time can read them later.
• See each other's location on an offline map. Each person chooses whether to turn location sharing on or off.
• Mark meeting points with team waypoints that everyone sees on the map.
• Send a Need Help alert to the members of your team. The alert is not sent to 112, rescue services or the Nelos team.

In good conditions, two radios talk to each other directly. Ordinary radios don't relay messages for each other; to go farther, a message has to pass through a repeater placed somewhere high, or a radio switched to Companion Repeater mode (which uses more battery).

LoRa radios in Europe use the band around 868 MHz. When you buy one, choose the version for Europe.

Without a radio, Nelos still gives you offline maps, movement history and personal waypoints on your phone. Messaging, creating teams and sharing location need a radio.

What to add to your 72-hour kit

You only need to add two things (three if your family members live far apart), but you have to prepare them while the network is still working.

• A handheld LoRa radio for each person. For example, the Wio Tracker L1 Pro: it comes with MeshCore pre-installed, connects to Nelos over Bluetooth, and its battery lasts up to about 5 days depending on use. See prices on the Devices page.
• A power bank for your phone, plus cables for both the phone and the radio. In the background, Nelos uses a little over 1% battery per hour on both Android and iOS*.
• If family members live far apart: a repeater placed somewhere high, such as on a roof or a high-floor balcony. A repeater has to be installed beforehand, not once the power is already out.

Keep the battery-powered FM radio in the kit too: it's how you hear official announcements.

What to do beforehand:

1. Install Nelos on everyone's phone and download the offline map of the area where you live.
2. Connect each phone to its own radio, create a family team and invite everyone.
3. Mark meeting points on the map with team waypoints.
4. Test it once: send a message from home to the school or workplace to learn the real range in your area.
5. Each time you check your 72-hour kit, charge the radios and power banks as well.

* In our real-world tests (about 18 hours per phone, mostly on the move, with background GPS on, the radio connected, and 5G and Bluetooth on), Nelos used about 1.2% battery per hour on a Galaxy S25 Ultra and 1.5% on an iPhone 13 Pro in the background. Actual use varies by phone, signal and settings.

A family communication plan for a power outage

Equipment only helps when the whole family knows what to do. A short plan agreed in advance matters more than expensive equipment.

• Times to check in. For example, at 8 a.m. and 8 p.m., each person taps Check in in Nelos. A Check-in sends your current location with a short message, stays on the team map for 24 hours, and shows who has received it.
• Two meeting points. One near home, and one outside your neighborhood in case you can't get home. Save both as team waypoints.
• Who picks up the children. Write down who collects the kids from school, and who takes over if that person can't get there.
• An out-of-area contact. A relative somewhere else; whoever can make a call lets this person know. Nelos only connects people within radio range, not people outside the area.
• A paper copy. Important phone numbers, meeting point addresses and check-in times, kept with the 72-hour kit.

Practice the plan once a year, for example on a weekend evening: turn off mobile data and Wi-Fi, then use only Nelos for an hour.

Limits to know

Nelos is a way for families to message each other when there's no signal, not a rescue system. Before you buy, be clear about the following:

• It can't call 112. A Need Help alert only reaches members of your team, not the Nelos team. To call for rescue with no signal, you need a satellite device or a PLB.
• Everyone needs a radio, set up in advance. You can't message someone who doesn't have a radio or hasn't joined the team.
• Range isn't fixed. Buildings, hills, antenna placement and repeaters all affect it. In a city without repeaters, two homes far apart may not be able to reach each other directly.
• Short messages and locations only. No voice calls, no photos.
• It still needs power. Phones need a power bank; radios and repeaters also need to be fully charged beforehand.
• It doesn't replace an FM radio. Nelos doesn't receive official announcements from the authorities.

The guide communication for emergencies and disasters explains in more detail when you need a satellite device or a PLB.

Frequently asked questions

What is the Preparedness Union?

It is the crisis preparedness strategy the European Commission published on March 26, 2025. Part of it is the advice that every household keep enough essential supplies for at least 72 hours.

Is Nelos recommended by the EU?

No. Nelos is not affiliated with the EU and is not on any official list. Nelos is one way to fill the family communication gap in a 72-hour kit.

Do you need a license to use a LoRa radio in Europe?

No separate license is needed. LoRa radios in Europe use the band around 868 MHz; buy the European version and leave the region setting as it is.

How many radios do you need?

One radio for each person who needs to send messages. If family members live far apart, add a repeater somewhere high.

How far can messages travel?

There is no fixed number. Range depends on buildings, terrain, antennas and repeaters, so test it in your own area while the network is still working.

Does Nelos cost anything?

Nelos is free to download and use, with no account or service plan. Nelos Pro is an optional one-time purchase. You only pay for the radios.

Can Nelos replace a satellite device or 112?

No. Nelos is only for communicating within your team; messages and alerts do not reach 112 or the Nelos team. To call for rescue with no signal, use a satellite device or a PLB.

Sources

• Cyprus Mail (Reuters): the EU advises the public to keep at least 72 hours of supplies, March 26, 2025
• EU Civil Protection Knowledge Network: Finland's 72-hour brochure
• INESC TEC: the blackout that left millions unreachable, May 13, 2025
• Telco Magazine: telcos disrupted by the Iberian power outage
• Xataka Android: messaging apps that work without internet, after the blackout, May 2, 2025

Nelos is an independent product, not affiliated with, sponsored by, or endorsed by the European Union or any government agency. This article is for reference only and is not emergency-response guidance; follow the advice of your local authorities.