NVIS
COMMANDER
v14 · PHYSICS ENGINE · UK · RESILIENT FETCH
☀️ Day
↻ Force Sync
🩺 Net Test
SFI
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SOLAR FLUX (10.7cm)
Proxy for F-layer ionisation. <70 weak, 70–120 moderate, >150 excellent. Drives foF2.
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K-INDEX
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GEOMAGNETIC
0–3 Quiet · 4 Active · 5–6 Storm · 7+ Severe. High K depresses foF2 at high latitudes (Scotland first).
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X-RAY
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SOLAR X-RAY CLASS
A/B quiet · C minor · M moderate (extra D-layer absorption applied) · X strong (blackout modelled on sunlit side).
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SUN χ
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SOLAR ZENITH ANGLE
Angle of the sun from vertical at your TX. Drives D-layer absorption — lower χ = more absorption on low bands.
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Solar Data (NOAA SWPC)
Ionosphere
// STATION PARAMETERS
Data Source
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DATA SOURCE
Auto:
Live foF2 from nearest ionosonde.
Offline:
Climatology from SFI + solar angle + season.
Manual:
Enter foF2 yourself.
📡 Auto (Live)
📅 Offline (SFI model)
⌨️ Manual Override
>> TARGETING COMPUTER
LOCATE
Awaiting Input...
foF2 (MHz)
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F2 CRITICAL FREQ (O-MODE)
Highest freq reflected at vertical incidence for the ordinary wave. The extraordinary (X) wave reflects up to ~foF2 + fB/2 (≈+0.7 MHz in the UK) — the engine accounts for this near vertical incidence.
h' (km)
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VIRTUAL HEIGHT
Apparent reflection altitude (virtual height — higher than the true F2 peak hmF2 due to group retardation). Typical 250–400 km. In Auto mode, derived from the ionosonde's MUF(3000)/foF2 M-factor where available.
Mode
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OPERATING MODE
Sets required SNR in a 3 kHz channel:
SSB:
+10 dB · voice
Data:
0 dB · PSK/RTTY
Weak-signal:
−15 dB · FT8/JS8
CW:
−10 dB · Morse
SSB (Voice)
Data (PSK/RTTY)
Weak-signal (FT8/JS8)
CW (Morse)
Distance (km)
Tx Power (W)
Antenna
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ANTENNA
Dipole:
Horizontal, high-angle — classic NVIS.
Inverted-V:
Slight pattern droop, forgiving feed height.
Vertical:
Low-angle DX, near-null overhead (kills NVIS).
Link budget assumes the far station uses the same antenna profile.
Dipole (Flat)
Inverted V
Vertical (Whip/Pole)
Antenna Ht (m)
Polarisation
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POLARISATION
Linear:
standard dipole/whip — ~4 dB average loss to O/X-mode splitting + Faraday rotation on an NVIS hop.
Circular (matched):
antenna matched to the characteristic wave (per Witvliet et al.) recovers most of that — ~1 dB.
Linear (standard)
Circular (matched)
Ground Cond
Farmland (Avg)
Rock/Urban (Poor)
Salt Water (Good)
Local Noise
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MAN-MADE NOISE
ITU-R P.372 environment categories:
Quiet rural 53.6 · Rural 67.2 · Residential 72.5 · Business/urban 76.8 (Fa at 1 MHz). Atmospheric noise is added on a power basis.
Quiet Rural
Rural
Residential/Camp
Business/Urban
// MISSION ANALYSIS
MUF (secant + X-mode)
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FOT (90% reliability)
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LUF (link-budget scan)
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PRIMARY FREQUENCY
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...
// LINK BUDGET
🔮 30-MIN FORECAST
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AVAILABILITY
0%
// TACTICAL VISUALIZATION
UK Coverage
Signal Path
Antenna Pattern
24h Schedule
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GREEN — WILL WORK (reliable)
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AMBER — MAY WORK (marginal)
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RED — WON'T WORK (skip/null)
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MAX RANGE
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ACF
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CCF unit
VERTICAL ELEVATION
AZIMUTH ORIENTATION
GAIN vs ANTENNA HEIGHT — WHY HIGHER IS NOT BETTER
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MUF
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FOT
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LUF
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NOW
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BEST CHANNEL
// CHANNEL PLAN
Designation
Freq (MHz)
Status
Margin
Wave
System Initialized v14 (Physics Engine — Resilient Fetch)