Skip to content

Single Path Prediction

Predict the signal-to-noise ratio for any HF path from the command line.

Usage

ionis-validate predict \
    --tx-grid <grid> --rx-grid <grid> \
    --band <band> \
    --sfi <value> --kp <value> \
    --hour <utc_hour> --month <month> \
    --day-of-year <day>

Parameters

Parameter Required Description Example
--tx-grid Yes Transmitter grid (4-char Maidenhead) FN20
--rx-grid Yes Receiver grid (4-char Maidenhead) IO91
--band Yes Band (160m, 80m, 60m, 40m, 30m, 20m, 17m, 15m, 12m, 10m) 20m
--sfi Yes Solar Flux Index 140
--kp Yes Kp geomagnetic index 0-9 3
--hour Yes UTC hour 0-23 14
--month Yes Month 1-12 6
--day-of-year Yes Day of year 1-366 172

Example

ionis-validate predict \
    --tx-grid DN26 --rx-grid IO91 \
    --band 20m --sfi 150 --kp 2 \
    --hour 14 --month 6 --day-of-year 172

Output:

============================================================
  IONIS V22-gamma — Path Prediction
============================================================

  TX Grid:    DN26 (46.5N, -113.0E)
  RX Grid:    IO91 (51.5N, -1.0E)
  Distance:   7,842 km
  Band:       20m (14.097 MHz)
  Conditions: SFI 150, Kp 2.0
  Time:       14:00 UTC, month 6, day 172

  TX Solar:   +49.1 deg
  RX Solar:   +54.2 deg

  Raw Model:  +0.432 sigma
  Override:   not triggered
  Final SNR:  +0.432 sigma (-6.8 dB)

  Mode Verdicts:
    >>> WSPR   OPEN    (threshold: -28 dB)
    >>> FT8    OPEN    (threshold: -21 dB)
    >>> CW     OPEN    (threshold: -15 dB)
        RTTY   closed  (threshold: -5 dB)
        SSB    closed  (threshold: +3 dB)

How It Works

The predictor:

  1. Converts Maidenhead grids to latitude/longitude
  2. Computes path geometry (distance, azimuth, midpoint)
  3. Calculates solar depression angles for both endpoints
  4. Engineers 17 features matching training exactly
  5. Runs the V22-gamma checkpoint (single forward pass)
  6. Applies PhysicsOverrideLayer (clamps high-band night paths if triggered)
  7. Denormalizes the sigma output to dB using per-band WSPR norm constants
  8. Applies mode thresholds to produce open/closed verdicts

PhysicsOverrideLayer

After neural inference, a deterministic post-processing clamp is applied:

  • Condition: freq >= 21 MHz AND both endpoints below -6 deg solar depression AND prediction > -1.0 sigma
  • Action: Clamp prediction to -1.0 sigma
  • Purpose: Close high bands (15m, 12m, 10m) when both endpoints are in darkness

The override status is shown in the output as "triggered" or "not triggered."

Mode Thresholds

Mode Threshold What It Means
WSPR -28 dB Beacon minimum — signal floor
FT8/FT4 -21 dB Digital decode limit
CW -15 dB Readable by experienced operator
RTTY -5 dB Machine-copy reliable
SSB +3 dB Voice-quality communication

A prediction of -6.8 dB means WSPR, FT8, and CW will work. RTTY is marginal. SSB needs a stronger path.

Tips

  • Try different hours: HF propagation changes dramatically by time of day. Sweep --hour 0 through --hour 23 to find your opening.
  • Check SFI sensitivity: Compare --sfi 70 (solar minimum) vs --sfi 200 (solar maximum) to see how much the sun matters for your path.
  • Storm impact: Compare --kp 1 (quiet) vs --kp 5 (moderate storm) — high-latitude paths are most affected.
  • Band comparison: The same path may be open on 20m but closed on 10m depending on solar conditions.
  • Day of year: Use --day-of-year to capture seasonal effects. The model uses this for solar depression angle calculations.