A modern EasyPal alternative for digital SSTV
EasyPal put full-quality photo files on HF — but it has had no updates since its author became a Silent Key in 2014. Open Signal delivers the same byte-exact photo transfer on an actively-maintained waveform, and adds classic SSTV across six families and a self-filling logbook.
Why look for an EasyPal replacement?
EasyPal was a landmark: a DRM-based mode that let amateurs send real image files — JPEGs, not analog frames — through a 2.4 kHz SSB channel, arriving pixel-perfect. But its author, Erik Sundstrup (VK4AES), became a Silent Key in October 2014, and the program has not been touched since. On modern Windows, with modern audio stacks, that leaves operators nursing a program frozen a decade ago.
Open Signal takes the idea forward. It sends the actual photo file byte-exact over the air on its own OFDM waveform with fountain forward-error-correction, so a picture rebuilds from any sufficient set of received bursts — and late-joining stations still complete. It is one self-contained executable, actively developed, and it does far more than image files.
What you keep — and what's better
- Real files over radio. Send a JPEG and it arrives byte-exact, exactly the EasyPal experience.
- Same interface, same radio. Anything that ran EasyPal or PSK31 — a Digirig, a SignaLink, USB-audio rigs — runs Open Signal.
- Now with classic SSTV too. Six families (Martin, Scottie, Robot, Wraase, PD and MMSSTV's MP/MR) with automatic mode detection — EasyPal never did analog SSTV.
- Hybrid cloud mode. Tick one box to send only a cloud URL: full quality in about five seconds of airtime when both ends have internet.
- A logbook that fills itself. Every exchange is logged with callsign, CAT frequency, mode and grids — pushed live to Wavelog/Cloudlog, eQSL and UDP ADIF.
Open Signal vs EasyPal vs MMSSTV
Where EasyPal covers digital image files and MMSSTV covers analog SSTV, Open Signal does both — and stays maintained.
| Feature | Open Signal | EasyPal | MMSSTV |
|---|---|---|---|
| Still maintained | Yes — active development (v0.22.3) | No — author SK since 2014, no updates | No — legacy freeware, unchanged for years |
| Digital (error-corrected) pictures | Yes — OFDM + fountain FEC | Yes — DRM waveform | No — analog SSTV only |
| Classic analog SSTV | Yes — six families incl. MP/MR, auto-detect | No | Yes — the reference implementation |
| Send the real photo file byte-exact | Yes | Yes | No |
| Send full quality via internet + radio URL | Yes — hybrid cloud mode (~5 s) | No | No |
| Extra software needed | None — one self-contained .exe | None, but DRM setup is fiddly | Sound-card + often virtual audio cables |
| Self-filling logbook + eQSL/Wavelog/ADIF | Yes | No | No |
| CAT rig control & auto frequency logging | Yes — Kenwood/Elecraft/Yaesu/Icom | No | No |
One honest caveat: Open Signal is not wire-compatible with EasyPal. To exchange pictures you both run Open Signal. True EasyPal/HamDRM interop would require a DRM modem, which is on the roadmap rather than in the product today.
EasyPal & Open Signal — questions
Is EasyPal still being developed?
No. EasyPal was written by Erik Sundstrup (VK4AES), who became a Silent Key in October 2014. There have been no updates since, so it receives no fixes for new versions of Windows, audio drivers or codecs.
Can Open Signal decode EasyPal transmissions?
Not on the air. EasyPal uses a DRM (Digital Radio Mondiale) modem; Open Signal uses its own OFDM waveform. Open Signal gives you the same result — the actual photo file, byte-exact — on a more robust, actively-maintained waveform, plus classic SSTV that EasyPal never had.
Do I need to change my radio or interface to switch?
No. If your sound-card interface (Digirig, SignaLink, or a rig with USB audio) worked for EasyPal or PSK31, it works for Open Signal. Open Signal is a single self-contained Windows executable — nothing else to install.
More about Open Signal
Bring digital pictures back to your shack
Open Signal picks up where EasyPal left off — actively maintained, one executable, with SSTV and logging built in.