Frequently Asked Questions

Radar is a privacy-first, off-grid communication app for Android. It connects you with nearby people using Bluetooth LE and Wi-Fi Aware mesh networking, so you can chat and share your location even when there's no mobile signal, no Wi-Fi, and no internet. When a connection is available, Radar also uses an end-to-end encrypted internet relay to reach users further away. It pairs all this with a live radar-style map, emergency SOS broadcasts, and 250+ real-time data feeds — with no account, phone number, or email required.

Radar is an Android app that lets you communicate with nearby people without relying on mobile networks or Wi-Fi. It uses Bluetooth LE, Wi-Fi Aware, and local networking to create a mesh between devices, plus an end-to-end encrypted internet relay as a fallback. You can see nearby users on a radar-style map, send encrypted messages, broadcast emergency SOS alerts, and monitor live data feeds for earthquakes, aircraft, floods, and more. Think of it as a communication layer that works when everything else doesn't.

Anyone who wants to stay connected when normal communications fail — or who wants communication that doesn't depend on a centralised service. That includes preppers and survivalists, outdoor adventurers and hikers, festival and event goers in poor-signal crowds, travellers in countries with internet censorship, journalists and activists needing private comms, and anyone who just wants a privacy-first alternative to big-tech messaging apps.

No — none whatsoever. Radar generates a random UUID on first launch and that becomes your identity. No phone number, no email address, no account sign-up, no password. We deliberately designed it this way to protect your privacy. If you ever want to start fresh, you can reset your identity at any time via Settings → Device Identity Reset.

No. There is no sign-up, no login, and no password. Just install Radar and open it — you're ready to go immediately. On first launch the app generates a random, anonymous device identity (a UUID) for you behind the scenes. Because there's no account, there's nothing to hack, leak, or hand over, and nothing tying your activity to a real-world identity.

No. Unlike WhatsApp, Signal, and Telegram, Radar never asks for a phone number to register or function. Your identity is a random UUID, not a number. You can even use Radar on a device with no SIM card at all. (The optional SMS/MMS inbox can use your number to send texts if you choose, but that's entirely separate and opt-in.)

No. No email address is ever required or stored. There's no email verification, no marketing list, and no password-reset email — because there's no account to begin with. If you want to contact us for support you can email support@daltechnology.co.uk, but that's optional and unrelated to using the app.

You can install Radar on as many Android devices as you like, but each device generates its own independent identity and appears as a separate peer on the map. Because Radar has no central account, your chats and contacts are stored locally on each device and aren't automatically synced between them. Your Premium subscription, however, is tied to your Google Play account and works across all your devices.

To appear on your radar map and communicate over the Bluetooth/Wi-Fi mesh, yes — the other person needs Radar installed and running. However, Radar's built-in SMS/MMS integration works with any phone on any network, and the Matrix chat feature lets you communicate with anyone on a compatible Matrix homeserver without them needing Radar.

Not currently. Radar is an Android-only app, available on Google Play. iOS imposes strict background execution limits that prevent Bluetooth and Wi-Fi mesh networking from working reliably. We're monitoring Apple's evolving APIs and an iOS version may come in the future — see iOS Limitations for details.

Android 9 (API 28) or later is the minimum. Wi-Fi Aware (peer-to-peer NAN networking) requires Android 10 or later. Some advanced features — like precise nearby-device permissions — require Android 13+. Most modern Android phones from 2019 onwards are fully supported.

Yes — this is the whole point of Radar. Peer discovery, messaging, and emergency SOS all work fully offline using Bluetooth LE and Wi-Fi Aware to connect directly to nearby devices, with messages able to hop across up to 5 devices to reach further peers. The internet is only used as an optional extra channel for long-range delivery, map tiles, and live feeds. Pull the plug on the internet and the core radar and chat keep running.

Yes. Radar does not depend on cellular towers, a SIM card, or a mobile data plan. As long as another Radar user is within Bluetooth or Wi-Fi Aware range (typically 10–30 metres, extended via the mesh relay), you can find them and message them with zero bars of signal. This makes it ideal for dead zones, crowded events where networks are congested, and areas with no coverage at all.

Yes — anywhere there are other Radar users in range. Underground (subways, basements, bunkers), at sea (boats, ferries), and in remote wilderness, the local Bluetooth/Wi-Fi mesh works exactly the same because it doesn't need any infrastructure. The one limitation off-grid is that map tiles and live data feeds won't load without internet, but the communication layer — finding peers, chatting, and SOS — remains fully functional as long as peers are physically near each other.

Yes. Bluetooth Low Energy (BLE) is one of Radar's core offline channels. The app advertises its presence and scans for nearby Radar peers over BLE, then exchanges encrypted messages directly device-to-device — no pairing required. BLE is extremely power-efficient (closer to a fitness tracker than a phone call), and Radar duty-cycles the scanner to keep battery use low. Bluetooth needs to be switched on for offline discovery to work.

Yes, where supported. Wi-Fi Aware (also called NAN — Neighbour Awareness Networking) lets devices form direct peer-to-peer Wi-Fi links without any router or access point. Radar uses it alongside Bluetooth to give higher bandwidth for richer content and a more reliable mesh. It requires Android 10 or later and hardware support — not every phone has it, in which case Radar falls back to Bluetooth LE. You can toggle it in Settings.

Yes, as long as there are other Radar users nearby. Bluetooth LE typically reaches 10–30 metres through walls and floors; Wi-Fi Aware has similar range. Messages can hop across up to 5 Radar devices (the mesh relay) to reach their destination — all without any cellular, Wi-Fi, or internet access. So in a subway, a bunker, or a building with no signal, Radar keeps working as long as peers are in Bluetooth range of each other.

Yes for local communication. In Airplane mode you lose the internet relay, but Bluetooth LE still functions on most Android devices, allowing Radar to discover nearby peers and deliver messages directly device-to-device. Wi-Fi Aware also often works when enabled manually while in Airplane mode. You won't receive relayed messages from further away, but you'll still see nearby peers on the map and chat with them.

Yes, when available — but it's not required. The internet relay is one of several delivery channels. When internet is present, Radar uses it for long-range encrypted message delivery, map tile loading, and live data feeds. It falls back gracefully to Bluetooth LE, Wi-Fi Aware, or LAN if no internet exists. The mesh networking, peer discovery, and emergency SOS all work entirely offline.

Bluetooth must be on for Radar to discover nearby devices and exchange messages without internet. However, Radar uses Bluetooth Low Energy (BLE), which is extremely power-efficient — comparable to a fitness tracker, not a phone call. The scanner is also duty-cycled (5 seconds active per 30-second interval) to minimise drain. If battery life is critical, Radar will also function via Wi-Fi or internet relay alone.

Yes. Radar runs a foreground service that keeps Bluetooth advertising, peer scanning, and message delivery active when the app is minimised or the screen is off. Android requires a persistent notification in your status bar while this runs — this is intentional and transparent by design. Radar will keep monitoring for nearby peers and incoming messages even when you're not actively using it.

There is some impact, but Radar is designed to be power-efficient. BLE scanning is duty-cycled and uses a fraction of the power of regular Bluetooth. On a typical modern phone, expect roughly 3–8% additional battery drain per day with Radar running in the background. Disabling Wi-Fi Aware or reducing the map refresh rate in Settings will reduce consumption further.

Core services: Google Maps (map rendering), Firebase Cloud Messaging (push notifications when a message is waiting), and the Radar relay server (message relay and peer discovery). Premium features additionally use OpenSky Network (live aircraft), OpenStreetMap/Overpass and Google Places (points of interest), HERE Maps, and WiGLE. Critically, the peer-to-peer mesh works without any of these — Radar can communicate using only Bluetooth and Wi-Fi hardware when everything else is unavailable.

The radar map shows: nearby Radar contacts with their optional nickname and position; anonymous Bluetooth and Wi-Fi Aware devices in range; seismic events (earthquakes); points of interest such as hospitals, pharmacies, and emergency services; and — with Premium — live aircraft positions (via OpenSky), crowd-sourced Wi-Fi access point data (WiGLE), and rich POI details. You can also subscribe to 250+ live data feeds covering floods, wildfires, cyclones, CAP government alerts, aviation incidents, and more.

You can chat with any other Radar user nearby via Bluetooth LE or Wi-Fi Aware (no internet required), or with any Radar user anywhere via the encrypted internet relay. You can also send and receive standard SMS and MMS from within the app (works with any phone), and join Matrix federated chat rooms to communicate with anyone on a Matrix homeserver.

Yes. Any Radar user within your configured discovery range who has the app running will appear on your map with their optional nickname and approximate position. You can tap their marker to view their contact card and start chatting. Basic lets you receive messages from anyone and reply to existing chats; Premium lets you initiate first contact with a new peer.

Just open the app — the radar map and the surrounding "sweep" view automatically show any Radar users within range, with their distance and direction relative to you. Make sure Bluetooth, Wi-Fi, and location are enabled for the best discovery, and that the other person also has Radar running. Tap any marker to open their contact card and start a chat. You can adjust your discovery range in Settings if you want to see peers nearer or further away.

The most common reason is simply that nobody running Radar is physically within range of you yet — Bluetooth reaches only about 10–30 metres. Other things to check: make sure Bluetooth, Wi-Fi, and location permissions are granted and switched on; confirm location sharing isn't disabled in Privacy Settings; verify the background service is running (look for the Radar notification); and check your discovery range isn't set too small. As Radar's user base grows in your area, you'll naturally see more peers.

When peers are sharing GPS positions over the network, distance is calculated from those coordinates and is typically accurate to within a few metres, depending on each device's GPS fix. For purely offline Bluetooth discovery, distance is estimated from signal strength (RSSI), which is more approximate — walls, bodies, and interference can make a peer seem nearer or further than they really are. Treat the offline distance as a useful guide rather than a precise measurement.

Direction (bearing) is computed from your GPS position and the peer's GPS position, and your phone's compass orients the bearing as you turn. It's generally reliable for pointing you the right way, but accuracy depends on a good GPS fix at both ends and a calibrated compass — nearby metal, magnets, or an uncalibrated sensor can skew the heading. If the direction seems off, calibrate your compass by moving the phone in a figure-eight motion.

End-to-end encrypted messages use X25519 Diffie-Hellman key exchange and XChaCha20-Poly1305 authenticated encryption — the same cryptographic standards used by Signal and leading secure messengers. The sealed-sender design means the server cannot determine who is communicating with whom from the encrypted payload alone. The local message database is encrypted at rest with SQLCipher.

Radar isn't a replacement — it's a different category of tool. WhatsApp, Signal, and Telegram all require an internet connection and a phone number to register and function. Radar works without internet or a phone number, using Bluetooth and Wi-Fi mesh networking, making it uniquely valuable when networks are down, censored, or untrustworthy. For everyday internet messaging, those apps are polished and widely adopted. But if you need to communicate when the internet is gone — or when you want zero reliance on centralised servers and phone number registration — Radar stands alone. See the full feature comparison.

WhatsApp stops working the moment you lose internet, requires a phone number, and is owned by Meta — meaning your metadata (who you talk to, when, and where) feeds a vast advertising business. Radar needs no internet, no phone number, and no account, works device-to-device over Bluetooth and Wi-Fi when networks fail, and collects no advertising data. They solve different problems: WhatsApp is great for everyday online chat, but when the signal drops, the network is censored, or you want true anonymity, Radar keeps you connected where WhatsApp can't. See the Radar vs WhatsApp comparison.

Telegram also requires the internet and a phone number, stores your chats on its cloud servers, and only end-to-end encrypts "Secret Chats" — normal chats are not E2E encrypted. Radar requires no phone number and no internet, end-to-end encrypts relayed messages by default, stores nothing readable on any server, and keeps working offline via its Bluetooth/Wi-Fi mesh. If you value resilience when networks go down and strong default privacy over Telegram's cloud convenience, Radar is the better fit. See the Radar vs Telegram comparison.

Very. Radar is designed from the ground up to minimise data collection. No email address or phone number is ever required or stored. Your identity is a randomly generated UUID — pseudonymous by design. No email, no phone number, and no real name is stored on our servers. We don't sell your data, use it for advertising, or share it with data brokers. The optional nickname and gender shown to nearby peers are entirely up to you. See our full Privacy Policy.

Yes. Messages sent via the internet relay use end-to-end encryption (X25519 + XChaCha20-Poly1305) — the server stores only opaque ciphertext it cannot read. The local database is encrypted at rest with SQLCipher. All server communication uses HTTPS with replay attack prevention. An optional biometric lock (fingerprint/face) secures the app on open. You can wipe and regenerate all cryptographic keys at any time via Settings → Device Identity Reset.

Radar is built with safety in mind. You control what you share, who can see you, and you can block any user instantly. Local Bluetooth/Wi-Fi messages are physically short-range (typically under 30 m), limiting who can receive them. As with any communication tool, use it thoughtfully — only share your location with people you trust, and use Privacy Settings to restrict visibility if needed.

Other Radar users can see your approximate position on their map if you're within their configured discovery range and you have location sharing enabled. They'll see your optional nickname and position — but not your phone number, email, or real name unless you've chosen to use those as your nickname. You can make yourself invisible at any time by disabling location sharing in the app's Privacy Settings.

Only what you choose to share. Nearby Radar peers can see your current location (at whatever precision you share), your optional nickname, and your optional gender. No phone number, email address, or real name is ever visible to other users. All profile fields except your device UUID are optional — you can use Radar entirely anonymously.

Yes. Leave the nickname blank, don't set a profile photo, and set gender to "not specified" — other users will only see your position on the map under a generic label. Your device UUID is pseudonymous and not linked to any real-world identity. If you ever want a completely fresh identity, Settings → Device Identity Reset generates a new UUID and wipes all cryptographic keys.

Radar uses your location only to power its features — showing you on the map and computing distances to nearby peers — and you're always in control. We don't build a history of your movements, sell your location, or use it for advertising. Your position is shared with nearby peers only while you have location sharing switched on, and you can turn it off at any time in Privacy Settings or revoke the permission entirely in Android Settings. With sharing off, you can still browse the map without broadcasting where you are.

Only the peers within your discovery range can see your position, and only while you're sharing it. If you'd rather not reveal a precise pin, you can reduce your location precision or disable sharing altogether in Privacy Settings, so peers see only an approximate area — or nothing at all. You decide exactly how precisely, and with whom, your position is shared.

Yes — instantly. Just turn off location sharing in Settings → Privacy and you immediately disappear from other users' maps while still being able to use the rest of the app. You can re-enable it whenever you like. This gives you a quick "go invisible" switch whenever you want to stay off the radar.

No — not unless you choose to put it there. Radar never asks for your real name, and there's no way for other users to discover it. The only label other peers see is the optional nickname you set yourself, which can be anything (or left blank). Your underlying identity is a random UUID, not a name, number, or email.

Yes. Messages are end-to-end encrypted using X25519 key exchange and XChaCha20-Poly1305 authenticated encryption — the same class of cryptography used by Signal. Only you and the recipient hold the keys, so the relay server only ever sees opaque ciphertext it cannot read, and a sealed-sender design hides who is talking to whom. Messages stored on your device are also encrypted at rest with SQLCipher. (Standard SMS/MMS sent via the optional inbox uses the carrier network and is not end-to-end encrypted — that's a limitation of SMS itself.)

A Radar user near you can start a chat the same way you can start one with them — that's how nearby discovery works. However, you're always in control: you can block any user instantly, and because offline messaging is short-range over Bluetooth/Wi-Fi (typically under 30 m), only people physically near you can reach you. To stay completely private, disable location sharing so you don't appear on anyone's map in the first place. Note that initiating first contact with a brand-new peer is a Premium feature.

Yes. You can block any user instantly from their contact card or a conversation. Once blocked, you'll no longer receive their messages and they're removed from your active chats. You remain in full control of who you communicate with at all times.

Radar asks only for what its features genuinely need. Location (including background) powers the map and lets nearby peers find you; Bluetooth / Nearby Devices enable offline peer discovery and messaging; Wi-Fi supports Wi-Fi Aware mesh networking; and notifications alert you to incoming messages and SOS. The rest are optional and opt-in: Contacts (to merge friends into your contact list, never uploaded), SMS/MMS (for the unified texting inbox), and camera/storage (for sharing photos). You can grant or deny each one and change them anytime in Android Settings.

Location is central to what Radar does — it powers the radar map, lets nearby peers find you, and enables features like SOS broadcast with GPS coordinates. Background location access means your position stays updated even when the app isn't in the foreground, so other Radar users can see you on their map. You can disable location sharing at any time in Settings → Privacy, or revoke the permission entirely in Android Settings.

Radar optionally reads your Android address book to merge your existing contacts with discovered Radar peers in a unified contact list. If a friend is nearby and using Radar, they'll appear under their saved name rather than a random ID. No contact data is ever uploaded to our servers — it stays on your device. This permission is optional; you can use Radar without granting it.

Radar includes an optional unified SMS/MMS inbox that lets you send and receive standard text messages alongside your Radar chats. This feature is entirely opt-in and off by default, and can be disabled at any time in Settings → SMS Integration. Crucially, SMS content is never uploaded to our servers — it is stored only in the encrypted on-device database.

Your data is used only to power Radar's core features: displaying your position on the map for nearby peers, relaying messages when no direct path exists, sending push notifications when a message is waiting, and rendering the map. We don't use your data for advertising, profiling, or any commercial purpose beyond operating the app. See the full breakdown in our Privacy Policy.

No — never. We do not sell, rent, or share your personal data with third parties for commercial purposes. We do not use your data for advertising. Your pseudonymous UUID and current location are shared with nearby Radar peers for map display — that's the only sharing that happens, and it's the core function you signed up for.

No — Radar is a paid app that you purchase once from Google Play, and there are no ads. You can then use it indefinately without charge.

After that, you can choose:

• Basic tier that's included with no subscription (the radar map, encrypted messaging, offline Bluetooth/Wi-Fi mesh networking, and emergency SOS & Prepper tools).
• Premium inexpensive subscription that adds live web services like aircraft and marine traffic. You can also start chats with strangers.

You can choose:

• Radar is £1.99 via a one-time purchase from Google Play. Once you own it, the core features — radar map, messaging, offline mesh networking, emergency SOS, and the basic feed catalog — are included in the Basic tier with no subscription.
• An optional Premium subscription costs £0.99/month (cancel anytime via Google Play) unlocks the live web services like aircraft and marine traffic. You can also start chats with strangers. See Basic vs Premium for the full breakdown.

The reason for the subscription is that there is a genuine ongoing cost of paying for 3rd party web services.

None, ever. Not in Basic, not in Premium. There are no adverts, no sponsored content, no ad tracking, and no ad networks integrated into Radar. The app is funded by the one-time purchase and the optional Premium subscription, not by advertising.

Yes — this is exactly what Radar is built for. In emergencies like earthquakes, floods, storms, or power cuts, mobile networks often overload or go down entirely, but Radar keeps working because it doesn't depend on them. You can broadcast an emergency SOS alert with your GPS coordinates to nearby peers, coordinate over the offline mesh, and — when any internet is available — monitor 250+ live feeds for earthquakes, floods, wildfires, cyclones, and official CAP government alerts. For preparation tips see the Emergency and Prepper Guide pages.

Mostly, yes — and it's designed with exactly that scenario in mind. As long as your phone has battery and Android is running, Radar's Bluetooth and Wi-Fi Aware mesh will keep working: no internet, no cellular towers, no servers required. Peer discovery, messaging, and SOS alerts are all fully offline. The map tiles and live feeds need internet to load, but the communication layer itself is fully self-contained. Stock up on solar power banks and you're sorted. See the Prepper Guide.

If Person A and Person C are out of Bluetooth range of each other but both are within range of Person B, Radar will automatically route the message through B to reach C. This is the store-and-forward mesh: messages are held briefly by intermediate devices and forwarded as peers come into range, up to 5 hops. Loop prevention and time-to-live counters keep traffic from cycling. This means a message can travel much further than a single Bluetooth link — entirely without internet.

Radar is intended for users aged 13 and over. We do not knowingly collect personal information from children under 13. If you are a parent and believe your child has used Radar, contact us at support@daltechnology.co.uk and we will delete their data promptly. Because Radar requires no account sign-up, parental controls via Google Family Link can be used to restrict installation on a child's device. The app contains no ads, no in-app social feeds, and no way for strangers to contact your child without first appearing on the radar map — which requires the app to be running and location enabled.