The published window
ARISS announced Expedition 75 Series 33 on 23 September. Its event page gave the following times and signal parameters. This entry records that announcement, without claiming that every pass or every transmission was received.
| Item | Published detail |
|---|---|
| Start | Friday 2 October 2026, 09:00 UTC / 10:00 BST |
| End | Tuesday 6 October 2026, 15:55 UTC / 16:55 BST |
| Station | International Space Station, catalogue 25544 |
| Downlink | 437.550 MHz, with Doppler correction |
| Image mode | Robot 36 |
| Published transmission cycle | 36 seconds sending, then 2 minutes off |
| Theme | Student Education |
Source: ARISS Upcoming SSTV Events, checked 8 October. AOS and LOS are local pass predictions, separate from the multi-day event window.
Why the UHF frequency matters
Earlier ISS campaigns often used 145.800 MHz and PD120. Reusing those memories and that mode would miss the settings published for Series 33. At a fixed radial velocity, Doppler shift scales with carrier frequency: 437.550 MHz shifts about three times as much as 145.800 MHz. A receiver left on one UHF frequency can sound clean near the middle of a pass and become distorted near either end.
ARISS provides a 437.550 MHz Doppler memory sheet. Our UHF receiving note works through the five-memory option and the recording settings that make a later replay useful.
What to keep after a pass
Retain the original recording and the decoded image together. Record UTC start and end, approximate station location, receiver, antenna, channel width and whether the file contains demodulated audio or complex I/Q. Note tuning changes during the pass; a frequency step and a fade can leave different defects in the same picture.
If the image is incomplete, keep it anyway. Record whether its first line was missed, the signal faded during a row, or the decoder lost mode detection. A replay that starts before the VIS header can separate a missed start from poor signal quality. The Robot 36 data sheet and lossless sample provide a known waveform for checking the receiving path.
Gallery and the next event
The announcement directed receivers to the ARISS SSTV gallery for image submissions and event certificates. Consult the gallery's current event instructions for submission availability. A certificate deadline from an older campaign should not be assumed to apply to Series 33.
At the 8 October source check, the ARISS page had no later dated SSTV window. The activity page carries the latest source check and retains completed campaigns. Satellite entries there are reference targets; their operator schedules and current status still need to be checked.