Comparison

HamWatch vs CairnOS

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

HamWatch

This app provides amateur radio operators with essential tools on their Apple Watch. Monitor real-time space weather data and track POTA spots directly from your wrist. Customizable complications display your call sign on your watch face.

Highlights
  • Real-time space weather monitoring
  • 24-hour historical space weather charts
  • POTA spot tracking on wrist
  • Customizable watch face complications
  • Seamless iPhone and Apple Watch sync
  • Configurable auto-refresh intervals
Features
Read full description

Real-time ham radio data — on your Apple Watch. HamWatch gives field operators instant access to space weather, propagation conditions, and on-the-air spots, right from your wrist. SPACE WEATHER Live solar wind, Bz/Bt, and solar imagery from NOAA and NASA — including coronal hole monitoring and sunspot tracking. 24-hour charts included. SPOTS POTA, SOTA, and WWFF spots in real time. Filter by mode and band. Pull to refresh. Works on iPhone and Apple Watch. MAPS & TOOLS Azimuthal map centered on your GPS location shows true compass bearings to the world — aim your beam with confidence. WATCH FACE Complications for call sign, SFI, A-Index, and UTC. Choose which views appear on your watch from Settings → Configure Watch Views. The iPhone companion app adds larger charts and detailed data views. Everything syncs automatically between devices. https://www.hamwatch.app

About

CairnOS

Communicate off-grid using a mesh network of radios. Send messages, monitor network status, and explore maps without cell service or internet. Features include direct messages, channels, and on-device translation.

Highlights
  • LoRa mesh network communication
  • Direct messages and channels
  • On-device message translation
  • Network status dashboard
  • Offline map downloads
  • Message signing and verification
Features
Read full description

Cairn is a companion app for MeshCore LoRa mesh radios. Pair your radio over Bluetooth or WiFi and send messages through a community-built network of radios and repeaters, with no cell service, no internet and no account. MESSAGING - Direct messages, channels and room servers in one inbox, with filters - Public, private and hashtag channels; share or join a channel by QR code - Delivery status, with retry for failed sends - Emoji reactions, @mentions, forwarding, search and text selection - Path details for each message: every hop on a list and a map - On-device translation of incoming messages - Chats kept on a Cairn touch radio come over to the app when you pair - Block contacts or channel senders, filter keywords and mute conversations - Optional link previews, with a warning for known malware links DASHBOARD - Battery, network, radio, GPS, contacts and chats at a glance - Sunrise and sunset for your position and the radio's temperature sensor - Radio presets by region, or set frequency, bandwidth, spreading factor, coding rate and TX power yourself NODES & REPEATERS - Saved and heard nodes, with search, sort, filters and a card or list layout - A page for every node, with a map, readings and quick actions - Log in to your repeaters and room servers to see status, telemetry, neighbors and an SNR map, then change settings, access lists and regions or use the remote CLI - Send commands to your own companion radios over the mesh (MeshCore 1.18 firmware) - Telemetry history charts kept on your phone - Contact groups, QR sharing and a manual path editor SPECTRUM - Live noise floor and packet traffic on your frequency - Signal margin, airtime share and packets per minute - With a Cairn radio: the radio's own Channel view, with its trace, density heat map and 24-hour noise floor MAPS & GPS - Mesh map with standard, satellite and topographic layers - Live traffic layer: the links packets crossed lately, and each new packet as it arrives - Download map regions for offline use - Radio and phone GPS side by side, with a compass and a navigation HUD that points the way to any node TOOLS - Network Health, Scan for Nodes, Trace Path, Line of Sight with terrain and Fresnel zone, RX Log and a CLI terminal - Sign and verify messages with your radio's identity IN THE CAR & AROUND iOS - CarPlay: a dashboard of your radio, mesh, messages and location, a GPS page, and messages you hear and answer with Siri - Siri and Shortcuts: check radio status, send a message or send an advert - Live Activity and Dynamic Island with connection, battery and unread count - Multiple windows on iPad MAKE IT YOURS - Choose a color, gradient or photo background with glass cards over it - Give any node a photo or a color: its type's color, one of twelve shades or any color you pick - Backup and restore, plus CSV and GPX export PRIVACY Your messages travel radio to radio. Cairn has no accounts, no analytics and no developer server. Nothing is sent to the developer. REQUIREMENTS Requires a LoRa radio running MeshCore companion firmware, connected over Bluetooth or WiFi. Maps, link previews and Line of Sight elevation use the internet when it is available. Requires iOS 18 or later. Cairn is free and open source software under the GNU GPL v3, built on the work of the open-source MeshCore app community. Source code is linked from our support page.

Screenshots

HamWatch4 screens
CairnOS4 screens

Verdict

The call

The clearest difference is price: CairnOS at Free against HamWatch's $4.99. CairnOS also leads on update cadence (every 4 days vs every 10 days). HamWatch's advantage is iOS requirement (16.6 vs 18.0). On rating, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

CairnOS is free to download; HamWatch costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for HamWatch against 5.0 for CairnOS. Both are backed by a comparable volume of ratings — 3 and 2 respectively.

UpkeepUpdate frequency

HamWatch ships an update every 10 days, CairnOS every 4 days. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.

Scorecard4 real differences · 6 level
HamWatch versus CairnOS: the parameters behind the verdict, then further details
ParameterHamWatchCairnOS
Price$4.99Free — better
Rating5.0 (3 ratings)5.0 (2 ratings)
Positive reviews100.0% of reviews—
Number of ratings3 — better2
Update frequencyEvery 10 daysEvery 4 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, Apple WatchiPhone, iPad
Requires iOS16.6 — better18.0
Further details — not scored
Size6 MB54 MB
Age rating+44+
DeveloperJames KrepelkaChristopher Van Hoose

Customer experience

HamWatch

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews4 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

CairnOS

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

HamWatch

No in-app purchases

None

CairnOS

No in-app purchases

Questions

Is HamWatch free?
HamWatch costs $4.99, with no in-app purchases.
Is CairnOS free?
CairnOS is free to download, with no in-app purchases.
Which has better reviews, HamWatch or CairnOS?
HamWatch and CairnOS are both rated 5.0 out of 5 on the App Store, from 3 and 2 ratings respectively.
Do HamWatch or CairnOS have ads?
Neither HamWatch nor CairnOS shows ads.
Which is updated more often, HamWatch or CairnOS?
HamWatch ships an update every 10 days, and CairnOS every 4 days. Most recently, HamWatch was updated on November 2, 2026 and CairnOS on October 31, 2026.

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