# Tethra: Signal & Dead Zone Map — Cell coverage & no-data alerts

> Cell coverage & no-data alerts (iPhone/iPad app by Raduly Sandor.)

- Source: https://appshunter.io/ios/app/tethra-signal-and-dead-zone-map/id6819051159 (this page in markdown: same URL + `.md`)
- Developer: [Raduly Sandor](https://appshunter.io/developer/1412358816)
- Category: Navigation, Utilities
- Price: Free with in-app purchases
- Age rating: 9+
- Requires: iOS 26.0 · 6 MB
- Languages: American English
- Released: 2026-10-29
- Data updated: 2026-10-30

## What is Tethra?

Ever lost signal just when you needed to send a message? Tethra shows you exactly where your phone has mobile data — on your commute, on the road, on the trail.

Tethra shows you where mobile data really works. It doesn't guess or borrow other people's coverage maps. It tests your connection right where you are and turns every check into your own personal coverage map, one hexagon at a time. Tethra gives you the facts and leaves the decisions to you. Each result is a snapshot of one place at one moment, and networks change, so your map grows more useful the more you explore.

YOUR OWN COVERAGE MAP
• Every check colours a hexagon: Strong, Fair, Weak or No signal
• No signal is drawn hatched, so dead zones stand out at a glance
• Each hexagon shows its latest result, how fast data responded and your history there
• Filter by all time, the last 30 days, or dead zones only
• Street map or satellite view

MAPS IN THE BACKGROUND
With location set to Always, Tethra checks as you go about your day — no need to open the app. Your map grows on its own.

TRIPS
• Start a trip for a dense map along your route: a check every 50, 100 or 250 metres
• Get an alert the moment signal is lost, and another when it's back
• Tethra keeps mapping even without signal, so you see exactly where it ends
• The last place with signal is marked on the map
• Follow your trip on the Lock Screen and in the Dynamic Island
• Every trip gets a summary: coverage along the route, longest dead zone, how often signal was lost

WARNINGS BEFORE DEAD ZONES
Tethra remembers where you lost signal before and warns you as you approach — send that important message first.

SAVED SPOTS & SEARCH
Save the places that matter and search for any address to see your coverage there.

PRIVATE BY DESIGN
• No account, no sign-up, no ads
• Your map and trips are stored on your iPhone
• Each check only opens a secure connection to test mobile data — nothing is sent

Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://radulysandor.github.io

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Tethra Premium | $1.99 | per month |
| Tethra Premium | $9.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Tethra Lifetime | $19.99 | one-time |


## Is Tethra safe?

Not enough ratings yet to assess Tethra.

## Is Tethra legit?

Tethra: Signal & Dead Zone Map appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Tethra is 75 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0.0 — 2026-10-29

No release notes.

## More apps by Raduly Sandor

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- [Nomika · Name days](https://appshunter.io/ios/app/nomika-name-days/id6811382315)
- [Corbel · Smoking Tracker](https://appshunter.io/ios/app/corbel-smoking-tracker/id6812255783)

All apps by Raduly Sandor: https://appshunter.io/developer/1412358816

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-30.*