Which radio and alerts do you need when networks are down?

Short answer. You need the phone alerts your country already sends, plus a radio that works without mains power. The US kit list names a "battery-powered or hand crank radio and a NOAA Weather Radio with tone alert" ¹. Finland asks for a radio running "on batteries or otherwise without mains electricity" ⁶. The City of Oslo advises a DAB radio for NRK, ideally battery-capable ⁸.

Why do you need a radio if your phone gets alerts?

Phone alerts and broadcast radio do different jobs, and each can fail in a different way.

In the US, Wireless Emergency Alerts (WEA) are mainly delivered by cell broadcast: "Every WEA-capable phone within range receives the message" ². FEMA says WEAs "are not affected by network congestion" ². That suits a first warning. They have limits, though. A phone will not receive one if it is switched off, in airplane mode, or not connected to a cell site broadcasting the alert, or if that site is under maintenance or out of service ². A US alert is also short: no more than 360 characters, with a 90-character version for older phones ². That is enough to say "go indoors", but not enough to give updates over hours or days.

Broadcast radio fills that gap. A radio receives without a mobile network, and one with its own power source keeps working when the grid is down and the phone is flat. The UK government says its phone alerts "will not replace local news, radio, television or social media" ⁴. In the Nordic countries, the outdoor siren tells you something is happening, and the radio tells you what it is and what to do. Sweden's agency tells people who hear the alarm to listen to Sveriges Radio P4 ⁵. Finland sends its official emergency warnings on the radio channels of Yle, the national broadcaster ⁷.

What kind of radio should you keep?

Official kit lists ask for a power source that does not depend on mains electricity. They differ on the rest.

Ready.gov also lists a "cell phone with chargers and a backup battery" in the same basic kit ¹. It tells households to replace expired items and to rethink the kit every year ¹.

Phaenyx does not rate radio models. Check the bands your country uses before you buy. In Norway, for example, the City of Oslo points to DAB for NRK ⁸.

What is NOAA Weather Radio?

NOAA Weather Radio All Hazards is a US network of "more than 1000 transmitters, covering all 50 states" ³. It broadcasts official warnings, watches, forecasts and other hazard information "24 hours a day, 7 days a week" ³. It uses seven frequencies in the VHF public service band: 162.400, 162.425, 162.450, 162.475, 162.500, 162.525 and 162.550 MHz ³. These are not on an ordinary FM dial, so you need a receiver with a weather band.

Warnings carry a 10-second, 1050 Hz tone that "serves as an audible attention signal" ⁹. Many receivers can sit in a muted standby or alert mode and switch on when an alert arrives; depending on the model, they react to that tone or to a digital code ⁹. Ready.gov names a NOAA Weather Radio "with tone alert" in its kit list ¹. Receivers that use SAME (Specific Area Message Encoding) are programmed with the codes of the states and counties you want alerts for ¹⁰.

Which broadcasters are official emergency channels?

Some countries name one broadcaster as the official crisis channel. Others leave it open.

• Sweden. Important Public Announcements (VMA) go out on Sveriges Radio P4, SVT, SVT teletext, and commercial radio and TV, as well as apps and text messages ⁵. People who hear the outdoor signal should go indoors, close windows and doors, and listen to P4 or turn on the TV or teletext ⁵. The national information number is 113 13 ⁵.
• Finland. The Finnish Meteorological Institute says emergency warnings "are issued on the radio channels of the Finnish Broadcasting Company (Yle)", and on television if needed ⁷. The government guide adds that warnings also go out on the 112 Suomi app and on websites ⁶.
• Norway. According to the City of Oslo, NRK has a special responsibility to inform the public during national crises. "The primary emergency channel is NRK P1, but all NRK channels can be used" ⁸.
• United States. NOAA Weather Radio carries National Weather Service warnings around the clock ³. Phone alerts arrive through WEA ².
• United Kingdom. The government's main warning tool is Emergency Alerts on phones ⁴. The government says these alerts "will not replace local news, radio, television or social media", and drivers who cannot stop safely can check live radio ⁴. Phaenyx has not found a UK government page that names one official emergency radio station.

What do the sirens mean, and how do they link to the radio?

Sirens reach people who are outdoors or not looking at a phone. They only tell you to act and to find information.

In Sweden, the Important Public Announcement signal is a tone of 7 seconds followed by 14 seconds of silence, repeated for 2 minutes ⁵. The system is tested at 15:00 on the first Monday of March, June, September and December that is not a public holiday, followed by the all-clear at 15:05 ⁵. The all-clear is a continuous tone lasting 30 seconds ⁵. The emergency alarm (beredskapslarm) sounds for 30 seconds, stops for 15, and repeats for 5 minutes ⁵. The air raid warning is short bursts of 2+2 seconds for 2 minutes ⁵.

In Finland, the public warning signal is "a rising and falling sound that lasts for one minute" ⁶. If you hear it, the official advice is to go indoors immediately, then follow the emergency warning on the radio, the 112 Suomi app or websites ⁶.

In both countries, the radio carries the detail. A radio that works during a power cut is what turns a siren into instructions.

How do phone alerts work in the US and UK?

In the US, WEA is free. It does not count against texting limits, it is "not subscription based", and you do not need to share personal information to receive it ². Each alert has a distinct tone and vibration, repeated twice ². Alert types include National, Imminent Threat, Public Safety and AMBER alerts ². Some can be switched off in the phone's notification settings ².

In the UK, an Emergency Alert can make "a loud siren-like sound, even if it's set on silent". The sound and vibration last "about 10 seconds" ⁴. The government does not need your phone number or location to send one ⁴.

A cell broadcast alert does not replace a radio. When the phone is off, flat or out of range of a broadcasting tower, it receives nothing ².

What official agencies recommend

Where agencies differ, the difference is mostly about the band (FM, DAB or the US weather band) and about which broadcaster is named. They agree on the core point: keep a radio that does not need the grid.

Finland's guide also asks households to be ready to cope on their own for at least 72 hours ⁶, with the radio on its home supplies list ⁶.

Frequently asked questions

Is a hand crank radio enough on its own?

Ready.gov lists "battery-powered or hand crank radio" as one item and adds "extra batteries" separately ¹. A crank model that also takes batteries covers both.

Will my phone still get alerts if the mobile network is overloaded?

In the US, FEMA says Wireless Emergency Alerts are not affected by network congestion, and are mainly delivered by cell broadcast ². The phone must still be on, out of airplane mode and in range of a tower sending the alert ².

Can an ordinary FM radio receive NOAA Weather Radio?

No. NOAA Weather Radio uses seven frequencies between 162.400 and 162.550 MHz in the VHF public service band ³. You need a receiver with a weather band.

What station should I tune to in a Nordic crisis?

Sweden: Sveriges Radio P4 ⁵. Finland: Yle radio channels ⁷. Norway: NRK P1, which the City of Oslo calls the primary emergency channel ⁸.

How do I know if a siren is only a test?

In Sweden, tests are at 15:00 on the first non-holiday Monday of March, June, September and December, with the all-clear at 15:05 ⁵. Outside those times, treat the signal as real and turn on the radio.

Get the kit that matches your country's list

Official lists differ by country, mostly on the radio band and the broadcaster they name. Your Phaenyx plan names the alert channels of your country. Build your Phaenyx plan.

Sources

1. Ready.gov (FEMA) — Build A Kit — https://www.ready.gov/kit (accessed 2026-10-20)
2. FEMA — Wireless Emergency Alerts — https://www.fema.gov/emergency-managers/practitioners/integrated-public-alert-warning-system/public/wireless-emergency-alerts (accessed 2026-10-20)
3. National Weather Service (NOAA) — NOAA Weather Radio All Hazards — https://www.weather.gov/nwr/ (accessed 2026-10-20)
4. UK Government (GOV.UK) — About Emergency Alerts — https://www.gov.uk/alerts (accessed 2026-10-20)
5. Myndigheten för civilt försvar (MCF) — About the warning and information systems — https://www.mcf.se/en/advice-for-individuals/civil-defence-shelters-evacuation-and-warning-systems/public-service-announcement-and-other-varnings/about-the-warning--and-information-systems/ (accessed 2026-10-20)
6. Suomi.fi (Finnish government) — General instructions on preparedness, home emergency supplies and on what to do in different situations — https://www.suomi.fi/guides/preparedness/how-to-prepare-for-incidents-and-crises/general-instructions-on-preparedness-home-emergency-supplies-and-on-what-to-do-in-different-situations (accessed 2026-10-20)
7. Finnish Meteorological Institute — Emergency warnings — https://en.ilmatieteenlaitos.fi/emergency-warnings (accessed 2026-10-20)
8. Oslo kommune — Informasjon om beredskapssituasjoner og varsling ved kriser — https://www.oslo.kommune.no/beredskap-og-egenberedskap/informasjon-og-varsling/ (accessed 2026-10-20)
9. National Weather Service (NOAA) — NWR Warnings — https://www.weather.gov/nwr/nwr_warning (accessed 2026-10-20)
10. National Weather Service (NOAA) — NWR Specific Area Message Encoding (SAME) — https://www.weather.gov/nwr/nwrsame (accessed 2026-10-20)