Spektrum TLM viewers compared
There are a few ways to look at a Spektrum telemetry log. This is a fair overview, with the strengths of each option. Facts about other tools come from their own product pages and release notes as of November 2026, and can change. We have not installed or tested the other programs ourselves.
The options
| Option | How it runs | Platforms | Good to know |
|---|---|---|---|
| TLMscope | In the browser, nothing to install | Any current browser: Windows, macOS, Linux, Android, iOS | Free, no account, files stay on your device. English and German. Plain-language summaries and ratings, charts, GPS map with 3D replay, battery ageing across flights. Reads Spektrum logs only. No export. |
| TLM Viewer | Desktop program, download | Windows; on a Mac only through a Windows emulator, not on Android, according to its documentation | A long-standing free tool, open source (AGPLv3) since August 2026 with its source code on GitHub. Graphs, raw sensor data, session editing, export to CSV, KML (Google Earth) and TLM. Reads old and damaged log formats and many more sensors, for example turbines, combustion engines, PowerBox and Crossfire. English only. |
| Log Explorer | Desktop program for Windows, paid, with an Android companion app | Windows and Android; macOS and Linux are claimed on the product page | From $10 (pay what you want), with a license key tied to the Windows hardware ID. Reads FrSky Ethos and OpenTX logs and, according to its release notes since v3.0, Spektrum and Jeti logs. Keeps a library per model with notes and tags, compares flights, tracks battery resistance over time, links video files and can export a transparent overlay video. Also covers cost tracking, weather and model setup files, which are outside TLMscope. |
| Code libraries and small projects | Code for developers | Depends | For example a Ruby gem and an Android reader on GitHub. Useful to build your own tools; the Android project describes itself as being in early development. |
When to use which
- Pick TLMscope if you want a quick, readable answer to “what happened in this flight” on any device, without installing anything or uploading data.
- Pick TLM Viewer if you work on Windows and need to export data (CSV, KML) or to edit and save logs again.
- Pick Log Explorer if you fly several radio systems, want a library of flights per model with notes, compare flights side by side or make overlay videos. Its price and the Windows license are the cost.
- Use both: they read the same files. Both are independent projects; neither is made by Spektrum.
Where TLMscope is different
- It runs in the browser on any computer and on phones, with nothing to install.
- It explains flights in plain language and rates them in four levels, with the exact values one click away.
- It follows each Smart battery across flights and estimates its remaining life.
- It finds thermals and shows them on the map and in the replay.
- It speaks English and German, and its source code is public on GitHub under the MIT licence.
Honest limits of TLMscope
- Only logs from NX and iX transmitters have been tested so far. See Supported transmitters and sensors.
- There is no export to CSV or KML yet.
- There is no flight comparison, no library of flights across visits and no notes or tags. Log Explorer has all of these.
- Log Explorer reads more radio systems. Its Spektrum support is newer than its FrSky support, and we have not compared the two programs on the same log file.
- It reads Spektrum logs only; EdgeTX logs are planned.
Frequently asked questions
What is the best viewer for Spektrum TLM files? #
It depends on what you need:
- TLMscope is the quickest way to understand a flight on any device, in the browser and without installing anything.
- TLM Viewer suits Windows users who want to export data to CSV or Google Earth.
- Log Explorer suits pilots who fly several radio systems and want a flight library.
Can I view Spektrum TLM files online? #
Yes. TLMscope is an online TLM viewer: open the page, drop the .TLM file and the flights appear. The file is read in your browser and is not uploaded to a server.
Does TLM Viewer run on a Mac? #
According to its documentation, TLM Viewer is a Windows program that runs on a Mac only through a Windows emulator. TLMscope runs in Safari, Chrome or Firefox on a Mac directly.