What Open Signal needs to run
Short version: 64-bit Windows 10 or 11, or 64-bit Linux. Windows 7 and 8.1 cannot run it at all, and neither can a 32-bit machine. This page says exactly where the line is and why, so nobody spends an evening troubleshooting something that was never going to start.
What you need
| Operating system | Windows 10 or Windows 11 · 64-bit |
|---|---|
| Or | 64-bit desktop Linux — tested on Ubuntu 22.04 and 24.04 |
| Processor | Any 64-bit x86 CPU with SSE2 (everything from about 2007 on) |
| Memory | 2 GB, though 4 GB is a more realistic floor with a browser open |
| Disk | About 100 MB — one self-contained executable, nothing else to install |
| Audio | A sound-card interface, or any USB audio device, or the microphone |
| Internet | Not needed for the radio side. Only for hybrid sends, the map and updates |
There is nothing else to install. Open Signal ships as one self-contained executable with the runtime, the DSP, the SSTV codecs and the database compiled in — no .NET download, no FLDIGI, no Hamlib, no virtual audio cable.
What will not work, and why
Windows 7 and Windows 8.1 — not supported, and not fixable. Open Signal is built on .NET 8. Microsoft ended .NET support for Windows 7 and 8.1 entirely; the last version that ran on them was .NET 6, which reached end of support in November 2024. The runtime this program is compiled against will not install on those systems. That is not a decision taken here and it is not something a workaround can get round.
32-bit Windows — will not start. Open Signal is a 64-bit program. A 32-bit installation of Windows cannot execute a 64-bit binary, so it fails immediately rather than running badly. This is the one that catches people out most often, because the machine may otherwise be running Windows 10 quite happily.
Very old 64-bit machines — may start, may not keep up. Decoding is real-time signal processing: the audio is handled in fixed blocks at 48 kHz and the work has to finish before the next block arrives. A processor from around 2006 to 2008 will launch the program but can struggle to hold that pace, which shows as stuttering audio and pictures that fail part-way rather than as an obvious error.
Below the floor, support cannot help. Said plainly rather than left for a ticket to discover: if the machine is 32-bit, or on Windows 7 or 8.1, there is no configuration to adjust and no setting that will change the outcome. Tickets are read and answered, but on an unsupported platform the honest answer is the same one this page gives.
How to check your machine — two minutes
On Windows
- Press the Windows key and type About your PC, then open it.
- Read System type. It must say 64-bit operating system, x64-based processor. If it says 32-bit anywhere, Open Signal will not run on that installation.
- Read Edition. It must be Windows 10 or Windows 11. Anything earlier is out.
If both of those are right, the software will install and start. Everything after that is setup rather than compatibility — the install guide covers it.
On Linux
Run uname -m in a terminal. It needs to print x86_64. An aarch64 result is a 64-bit ARM machine — a Raspberry Pi, for instance — and there is no ARM build.
Open Signal is tested on Ubuntu 22.04 and 24.04 and needs a desktop session; Wayland works through XWayland. Audio goes through ALSA, which PipeWire and PulseAudio both provide compatibility for automatically. See SSTV on Linux.
Other distributions generally work, but “tested” means those two Ubuntu releases — that is where a problem can actually be reproduced.
If your machine is below the line
Being told no is more useful with somewhere to go next. These all work without a modern PC.
- Use a WebSDR in a browser. Public receivers let you tune a real radio through a web page from anywhere, and the decoding can happen on any machine that runs a current browser — see receiving SSTV with an SDR. No radio, no licence, no fast computer.
- Borrow a newer machine to try it. The receive-only version is free permanently and needs no account, so trying it costs nothing but the download.
- A cheap second-hand desktop clears this floor easily. Anything built for Windows 10 — roughly 2015 onwards — is comfortably past the requirements, and these machines are inexpensive precisely because they are ordinary.
Does Open Signal work on Windows 7?
No, and it cannot be made to. Open Signal is built on .NET 8, and Microsoft ended all .NET support for Windows 7 and 8.1 — the last version that ran on them was .NET 6, which reached end of support in November 2024. The runtime the program is compiled against will not install on Windows 7, so this is not something a patch or a workaround can solve. Windows 10 is the floor.
My PC is from around 2006. Will it run?
Probably not, and the reason is usually 64-bit rather than speed. Open Signal is a 64-bit program, and machines from before roughly 2007 are often 32-bit only — a 32-bit copy of Windows cannot run a 64-bit executable at all, so it fails the moment you launch it. If the machine is 64-bit and running Windows 10, it will start, but decoding is real-time signal processing and an eighteen-year-old processor may not keep up.
How do I check whether my machine is 64-bit?
On Windows, press the Windows key, type "About your PC" and open it. Look at "System type": it needs to say 64-bit operating system, x64-based processor. If it says 32-bit, Open Signal will not run on that installation whatever else the machine can do.
It starts but pictures decode badly or the audio breaks up. Is that the hardware?
It might be, but check the ordinary causes first — they are far more common. Sound-card levels, Windows audio enhancements left on, and the wrong sideband account for most bad decodes. Work through the noisy-pictures guide before concluding the computer is at fault; a slow machine usually shows as stuttering audio and dropped frames rather than a picture that is merely poor.
What if my machine is below the requirements?
Then support cannot help, and it is fairer to say so than to spend your evening on it. Below the floor the problem is not configuration, so there is nothing to adjust. What does work: a public WebSDR in a browser needs no radio and no fast computer, and the receive-only version is free forever if you can borrow a newer machine to try it on.
Will there ever be a 32-bit or Windows 7 build?
No. Both would mean staying on a runtime Microsoft no longer supports, which would mean shipping security fixes that no longer exist. It is a small program written by one person, and maintaining a build for platforms that are themselves unsupported is not a reasonable use of that time.
Does the free receive-only version have lower requirements?
No — it is the same program with transmit disabled, so it needs the same operating system and the same 64-bit processor. The difference is the licence, not the build.
Raising a ticket
If your machine meets the requirements above and something is still wrong, that is worth a ticket — include your Windows edition and system type, and the build line from the bottom of the Receive screen. The helpdesk gives you a reference and replies come by email; licence holders are answered first and the aim is a reply within two working days.
If the machine is 32-bit, or running Windows 7 or 8.1, please read the section above first. There is no fix to send you, and saying so quickly is more use than a conversation that ends in the same place.
Meets the requirements? Start receiving for nothing
The receive-only version of Open Signal is free permanently — no account, no payment details, no expiry. If your machine is on the list above, it will run.