- Extract PathParser.valid_callsign?/1 and reuse from the calibration
Mix task instead of duplicating the regex.
- Document raise behavior on Aprs.recent_packets_with_paths/1 and
Aprs.station_positions/1 (already noted in moduledoc; @doc reinforces
for callers reading the function head).
- Note in the BandConfig guard comment why it sits before the Oban pause
(so a misconfig exits without leaving queues paused).
- Reword the band-mismatched-negatives note as a v1 limitation (no TODO
tag — codebase convention is zero TODOs).
- Print '<computed> / <attempted>' for both positive (HRRR-coverage) and
negative (random-baseline → HRRR) factor compute stages so an operator
can see how much of the corpus survived each filter.
- Guard at task entry: Mix.raise if BandConfig has no 144 MHz entry.
Without it the Recalibrator silently falls back to 10 GHz physics.
- random_baseline now draws from sample_size: max(n, 5_000) so small-n
fits don't cluster geographically.
- Wrap body in try/after Oban.resume_all_queues so iex -S mix workflows
don't leave Oban paused after the task returns.
Pulls verified RF hops from aprs.me's 24h packet retention, computes
factor vectors at each hop's midpoint via the existing Recalibrator,
and runs gradient descent against random-baseline negatives.
Dry-run: prints proposed weights but does NOT mutate band_config.ex.
Refuses to fit on <50 positive or negative samples.
