Getting Started with RTTYApp

RTTYApp turns plain text files into a RTTY (radioteletype) audio signal — the same 5-bit Baudot code that news wire services and teletype machines used for decades. You give it text; it produces the classic FSK “warble.” What you do with that audio is up to you: drive a real Teletype through a terminal unit, or put it on the internet where anyone can listen and decode it with a teletype, a sound-card decoder, or software like FLDIGI.

A great example of the second path: Daniel Jones (K6YIC) built a stream that replays WWII naval communications from the Nimitz Gray Book, timed to the original 1941–42 dates, so listeners hear history “as it happened.” This guide gets you to the same kind of setup.

This is the quick-start. For how the transmit queue and scheduling actually work — including the feed-by-historical-date technique — see the Queue & Scheduling guide.

1. What You’ll Need

A Windows PC (Windows 7 or newer).

A sound card — RTTYApp can generate the RTTY audio in software, so you do not need a vintage hardware modem to get started.

To drive a teletype: a terminal unit (TU) / current-loop interface between the PC audio and your machine.

To stream online: an Icecast server (your own or a host) plus a streaming tool — see §7 below.

Advanced/legacy: RTTYApp can also drive a real transmitter or a hardware modem like the HAL ST-8000A over an RS-232 COM port. That’s not covered here — most new users use the sound card.

2. Install

Download RTTYApp-Setup-21.0.exe below.

Run it. Windows may show a SmartScreen warning (“unknown publisher”) because the installer isn’t code-signed — click More info → Run anyway. It’s safe.

It installs to C:\RTTYApp (not Program Files, so the program can write its own settings and logs) and offers optional Desktop and “Launch when Windows starts” shortcuts. If you’re building an always-on stream, tick the startup option (see §8).

The installer includes everything needed to run, plus a starter configuration and a sample message, so a fresh install transmits something the first time.

3. First Run

Launch RTTYApp (Start menu or desktop). On first start you’ll see a KEY / Trial Mode dialog — just click OK (or Cancel). The software is fully functional either way; the key is a legacy leftover and isn’t required.

Out of the box, RTTYApp starts sending the included welcome.txt in a loop, so you’ll see it working immediately.

4. Basic Configuration

Settings live in C:\RTTYApp\RttyApp.ini (a plain text file — edit it, then restart RTTYApp). The essentials:

ITTYCallsign    = "YOURCALL"    // your amateur callsign
Baud            = "B45"         // 45.45 baud = 60 wpm, the RTTY standard
Mode            = "ITA2"        // Baudot; also MILITARY, TELEX, ASCII, PSK31

Then pick your transmit path — sound card (recommended) or hardware. To have RTTYApp generate the FSK audio directly:

ITTYSoundCardID = -1                 // -1 = auto-pick a card; or 1,2,3,4; 99 = off
ITTYFrequencies = 2125.00, 2295.0    // Mark / Space tones (standard RTTY)

Connect that sound output to your TU (§6) or your streaming tool (§7).

The sound card and the RS-232 data output can’t be used at the same time — pick one. Leave ITTYCommPort = "NULL" when using the sound card.

5. Sending Your Own Content

Put your message as a .txt file in C:\RTTYApp\data\.

List its file name in C:\RTTYApp\data\schedule_temp.lst (one file per line).

Keep the standard schedule.lst (which contains $reload) so the queue loops.

Reload the queue (File → Reload Queue) or restart RTTYApp.

Preparing text — a few rules that save headaches:

RTTY/Baudot is UPPERCASE with limited punctuation. Type in caps; RTTYApp translates many extended characters, but simpler is safer.

Keep lines to about 72 characters or fewer.

Watch carriage returns when pasting from a PDF: pasted text often looks wrapped but has no real line breaks, so it will run on when transmitted. Make sure every line ends in a genuine Enter/return.

For how ordering, looping, and $reload actually work, read the Queue & Scheduling guide.

6. Path A — Drive Your Own Teletype

Feed the sound-card audio into a terminal unit (TU), which converts the FSK tones into the current-loop signaling your Teletype machine expects, and it prints. The RTTYApp side is just the sound-card configuration in §4; the hardware side (TU choice, loop supply, machine wiring) is specific to your equipment — the teletype community (see §9) is the best resource for that.

7. Path B — Create Your Own Online Stream

This is how Daniel built the WW2 stream, all on one Windows PC:

RTTYApp (sound-card audio) → BUTT → Icecast server → listeners

Icecast is the streaming server that listeners connect to; it doesn’t capture audio itself, so a separate source client — BUTT, below — feeds it your sound-card output.

RTTYApp generates the RTTY audio out your sound card (§4).

BUTT — “Broadcast Using This Tool,” a free Windows app (danielnoethen.de/butt) — grabs that sound-card output and sends it to your Icecast server. In BUTT you select the audio input (the sound device RTTYApp is playing to) and enter your Icecast server address, port, mount, and password.

Icecast publishes the stream at a public URL like http://yourhost:8000/yourmount.

Listeners open that URL in a browser, a decoder like FLDIGI, or a real teletype fed from their speaker — and copy the RTTY.

A note on silence between messages. Icecast itself streams silence fine — a channel can sit idle for long stretches without dropping (the ITTY AUTOSTART channel does exactly that). The wrinkle is specific to the Windows client BUTT, which tends to stop the stream when it detects silence. If you hit that, check its silence/signal settings, or keep a faint continuous background tone feeding the same audio device so BUTT always sees a signal (that’s the workaround Daniel used). Don’t use RTTY diddle (continuous LTRS) for this — it keeps a receiving teletype hammering and punches blank paper tape on any listener running a tape punch.

Setting up the Icecast server itself is its own task — run your own or use a host. See the Icecast and BUTT documentation.

8. Running Unattended, 24/7

Use the installer’s “Launch when Windows starts” option so RTTYApp comes back automatically after a reboot or power blip.

Dedicate a machine to it. Cheap mini-PCs work fine (Daniel used a ~$39 Lenovo M73). This matters especially for the feed-by-date trick below.

Advanced — feed messages by historical date. Put each message in schedule_temp.lst stamped with its original date/time, run in Timer mode (uncheck No Timer on the Control menu), and set that PC’s clock to the target date. Each message then waits and rolls off at “its” time — replaying a day’s traffic in real time. Because the clock is deliberately set to the past, use a dedicated machine for this. Full details in the Queue & Scheduling guide, §7.

9. Updating & Getting Help

Updates: download the newer RTTYApp-Setup-<version>.exe and run it. It upgrades in place; your RttyApp.ini, your data\ content, and your settings are preserved — a new version never overwrites them.

Community & help: the GreenKeys teletype mailing list (mailman.qth.net/mailman/listinfo/greenkeys) is where the teletype crowd hangs out, and more RTTYApp documentation lives right here on rtty.com.

Welcome to the wire service. 73.