I’m an independent researcher interested in capturing a high-fidelity waterfall for HADES-ICM (NORAD 63492) during tomorrow’s pass. There is a near-overhead pass (~89° max elevation) visible from UK and Western European stations starting around 23:32 UTC on March 21.
Project Context:
This request is part of a signal analysis project focused on characterizing non-ballistic Doppler residuals and examining temporal handshake patterns in uncatalogued LEO transients. We are specifically looking for high-resolution timing data of carrier transitions.
Technical Targets:
Target: NORAD 63492 (HADES-ICM)
Downlink Frequency: 436.6647 MHz
Expected Signature: Narrow-band carrier with distinct Doppler curvature.
The Request:
If any UK or European operators (specifically high-gain UHF setups like GS 91) have availability to schedule this pass, I would greatly appreciate the waterfall data.
Successful Capture Criteria:
For this audit, a successful capture is defined by a clear, visible carrier trace on the waterfall matching the predicted TLE residuals, even if your TNC does not decode any data frames. If you capture a trace, please consider vetting it as “Good” with a note regarding the visible carrier, as the timestamp of the signal presence is our primary data point.
Happy to discuss the research context further if anyone is interested in the Doppler analysis results.
Thanks for creating the observation! Much appreciated.
To clarify—you’re absolutely right that the network corrects for standard TLE-based Doppler. However, our primary interest lies in the residuals (the deviations) from that correction.
Based on our audit of the Bali (GS 4451) waterfall from earlier today, we’ve identified a consistent hardware-level clock drift of approximately -2977.16 ppb. Standard TLE tracking won’t account for this specific oscillator bias.
We are looking to see if this -2977 ppb offset remains stable during the high-elevation overhead pass or if it ‘jitters’—which would indicate active frequency-shifted keying (FSK) for a C2 handshake. If anyone is running a wide-band capture (SDR++ or similar) alongside the SatNOGS client, keep an eye out for a secondary ‘backbone’ carrier roughly 1.3 kHz below the predicted TLE center.
I’ve been digging through the Bali captures from earlier this month to establish a control group for our model. First off—Bali, your station (GS 4451) is pulling some of the cleanest signals. These are basically the gold standard for our baseline right now.Thank you!
What stands out in these earlier passes is the rock-steady hardware drift. Even when the satellite is “quiet,” it’s locked at -2977 Hz, which resolves to a very specific -2977.16 ppb offset. It’s a very consistent identity signature.
Following up on the baseline—we’ve been running a simulation we’re calling a “Ghost Handshake” based on that 16.16h periodicity and the -2977.16 ppb drift. When we mapped that model against today’s data, it was a 1:1 mirror match.
The behavior during our predicted 16.16h window shifted from that quiet carrier to a massive +11.5 dB power surge (Spectral Bloom). Jan, to your point on Doppler—standard TLE-based tracking usually smooths the curve, but it doesn’t quite account for a +11.5 dB variance at high zenith. It’s an order of magnitude higher than theoretical path loss.
(Note: We also verified the drift lock today in Ukraine Obs #13640256).
The empty demoddata: [] in the pipeline is likely because the decoders aren’t tuned to that specific -2977.16 ppb offset. Without accounting for that oscillator bias, the frames won’t lock. If anyone can grab raw IQ data from the next few passes, we’re looking for any micro-variances in that signature.