About ThinLine Radio

Where it started

ThinLine Radio did not start as a product company. It started as Ohio RSN — just a scanner service. We ran it with subscriptions at first, then moved it to free. Rdio Scanner had no support for subscriptions, so every user who paid got an account created by hand. After a year or so, the person building it wanted to offer more, and had no idea how to program.

The first extra piece was basic two-tone alerts into Telegram, using two-tone detect and a program called Automatic Email Manager. About six months later we had grown out of that. We still did not know how to write code, so we hired someone to build a Python program. It cost about $300. That little program is what changed us: it was the first time we could see what the code was doing. We only ran it for about six months, but it was the door into everything after.

Next we built around Rdio Scanner, still glued to different Python servers, still alerting on Telegram. After about a year we decided to build a mobile app. We had no idea what we were doing. We did it anyway — still pre-ThinLine, still Ohio RSN, using Rdio Scanner plus about six other applications outside of it, mashed into one listener experience.

Another year of that got old. Adding something, taking something out, or fixing a break meant touching too many moving parts. The thought was simple: if we can build these apps, we can put the work into Rdio Scanner itself and stop running a zoo of tools. Rdio Scanner was Rdio Scanner, though. It did what it did. We needed a name for the thing we were actually trying to build.

Why it is called ThinLine Radio

We called it ThinLine Radio because we are first responders. It was built from what we needed in the field, and what we needed off the field — off duty, still catching calls from home. We took every application we used, whether we had built it or it was third-party, and started grinding those gears into one platform.

After a year of on-and-off development we had ThinLine Radio Beta. Rdio Scanner operators were already waiting on a first release. That release landed in December 2025. Since then it has been a lot of tuning and bug fixes reported by users and operators. We take pride in what we turned that foundation into. We still respect where it came from.

Rdio Scanner is an open-source project by Chrystian Huot, licensed under the GNU GPL v3. The core scanner, database schema, delayed audio, alert sounds, and API compatibility still come from that work. We did not take anything that was not published as open source. By the time Ohio RSN needed to keep moving, the upstream project had gone about three years without updates, and there was a lot of room to grow. ThinLine Radio is our continuation of that foundation — not a replacement of the credit. Ohio RSN could not wait any longer. Not “ThinLine Radio the brand.” Ohio RSN, the service people were already listening to.

After our December 2025 release, an API access policy was added. We believe that was retaliation. That policy violates the GNU GPL v3, and we ignore it.

Since the December release this has shaped into something we are proud of. We are committed to improving it and to listening to users and operators. We are not perfect. We aim to be.

What ThinLine Radio is

ThinLine Radio is a software platform, not a radio feed. We build and maintain the server, the web player, and the iOS and Android apps. The audio itself comes from operators — agencies, dispatch centers, and hobbyists — who run their own recorders, deploy their own ThinLine Radio instance, and decide entirely on their own what gets recorded, delayed, published, and who is allowed to listen.

That means every scanner you find through ThinLine Radio is the responsibility of the person or organization operating it. We do not originate, curate, or control the content of any feed, including those listed in our public directory.

Recorder compatibility

ThinLine Radio ingests from any radio recorder that is compatible with Rdio Scanner, as long as it can create audio files separated by conversations or transmissions. Operators supply their own recorder; supported options include:

• Trunk Recorder
• RTLSDR-Airband
• SDRTrunk
• voxcall
• ProScan
• DSDPlus Fast Lane