FAX mode
SP-17 B/W
SP-17 is a 17 s black-and-white analog image mode row, useful as a compact monochrome comparison point.
Reference onlyMode sample
BBC-style colour test card and app-generated audio
The image is generated locally for this mode's raster. For supported modes, the audio sample is encoded from that image with the SSTV Signal Desk transmitter code, then published as lossless FLAC for static playback.
No app-generated audio sample is published for this reference-only mode because no matching transmitter entry exists in the app code.
Mode spec
| Short name | SP-17 |
|---|---|
| Support status | Reference only |
| Spec status | Reference timing row from the OK2MNM SSTV mode-list PDF. |
| Duration | 17 s |
| Frame | 128 x 256 |
| Data lines | 256 |
| Public VIS | VIS 125 |
| Standard VIS code | 0x7D (125) |
| Extended/N-VIS | No |
| Color model | BW |
| Component sequence | Y |
| Line rate | 895.52 lpm |
| Public timing profile | Mode-list row gives 17 s total duration, 256 scan lines, 128 columns, and 895.52 lpm; line-level porch timing is not part of this catalog row. |
Strengths
- SP-17 has a concrete catalogue row: 17 s, 128 x 256, BW, VIS 125.
- SP-17's Y component order and 895.52 lpm line rate make it useful for comparing airtime, raster, and colour structure against related modes.
Tradeoffs
- SP-17 is not app-supported yet, so the 17 s / 128 x 256 row should be treated as reference data rather than a verified transmit preset.
- SP-17 still needs implementation-grade porch, sync, and pixel timing before an app-generated WAV/FLAC sample can be published with the same confidence as supported modes.
Source notes
OK2MNM SSTV Handbook chapter 5 lists SP-17 as BW, VIS 125, 17 s, 256 lines, 128 columns, 895.52 lpm. Black-and-white FAX/SSTV reference mode.
- SSTV Handbook Chapter 5: List of SSTV modesSSTV Handbook - accessed 2026-08-24Reference for analog SSTV mode names, VIS codes, durations, line counts, column counts, and line rates.