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NTMS Propagation Path calculator

Path Calculator

Point-to-point prediction over HRRR profiles, SRTM terrain and ITU-R P.676 / P.530.

31.8, -97.8 · EM11cs · 8.0 ft AGL

33.1, -96.6 · EM13qc · 60.0 ft AGL
A callsign resolves through QRZ's mailing address, then geocoding — the position may be off from where the station actually operates.
Band
Station

Path calculation complete.

HRRR 08:00z · 9/9 path points
Distance
188.3
km · 117.0 mi
Bearing
36.9°
true · rev 216.9°
Terrain
BLOCKED
115.1 dB diffraction
Propagation
79/100
GOOD
Margin
-56.4
dB over CW threshold
Terrain profile · SRTM 30 m + canopy + MS footprints
Line of sight 1st Fresnel Duct layer Horizon ray Common volume

Over the horizon: the two horizon-skimming rays intersect at the common volume348 m AGL at the midpoint (1043 m above the chord, 522 m above the 4/3 horizon), so its Fresnel zone (F₁ ≈ 37.6 m) clears with margin. The geometric line of sight is obstructed — buried 502 m below terrain at its worst point.

Great circle
31.773, -97.831 → 33.12, -96.615 · 36.9°
Loss budget · 10 GHz
FSPL (free-space) 157.9 dB
Gaseous (O₂ + H₂O) 1.3 dB
Diffraction 115.1 dB
Rain attenuation 0.0 dB
Total path loss 274.4 dB
Gas rate 0.0070 dB/km · H₂O 0.0000 dB/km/g · O₂ 0.0070 dB/km
Path abs. humidity avg 12.8 g/m³
Power budget
TX power 20.0 dBm (100.0 mW)
TX antenna gain 30.0 dBi
Feed loss (×2) -2.0 dB
EIRP 48.0 dBm
Path loss -274.4 dB
RX antenna gain 30.0 dBi
RX power -196.4 dBm
Sensitivity (CW, 500 Hz) -141.0 dBm
Margin -56.4 dB
Path weather · HRRR average of 9 samples
Temperature
72.5 °F
22.5 °C
Dewpoint
59.7 °F
15.4 °C
T/Td gap
12.9 °F
7.1 °C
Abs. humidity
12.8
g/m³
Pressure
970.2
mb
PWAT
22.9
mm
BL depth
230.1
m AGL
Refrac. gradient
-119.6
N/km · super-refractive
Propagation factors · 10 GHz 79/100
Rain
100 14%
Humidity
90 13%
PWAT
90 11%
Season
68 11%
T-Td Depression
85 10%
Refractivity
82 10%
Pressure
88 10%
Sky Cover
50 8%
Wind
50 8%
Time of Day
55 4%
Atmospheric profile HRRR 3 km Valid 2026-05-15 08:00 UTC · 9 samples
Point Lat, lon Temp Dewpt Press dN/dh BL m PWAT Duct
Source 31.8, -97.8 20.1 °C 15.5 °C 970.2 mb -93.3 166.3 21.7 mm
13% 31.9, -97.7 20.7 °C 14.8 °C 984.4 mb -78.4 88.3 22.5 mm
25% 32.1, -97.5 21.6 °C 15.0 °C 990.4 mb -96.9 207.3 22.5 mm
38% 32.3, -97.4 22.3 °C 15.0 °C 985.3 mb -104.0 246.5 23.4 mm
Midpoint 32.4, -97.2 22.7 °C 14.8 °C 983.7 mb -119.6 232.5 23.2 mm
63% 32.6, -97.1 22.5 °C 15.4 °C 987.9 mb -104.2 252.5 24.0 mm
75% 32.8, -96.9 24.2 °C 16.2 °C 991.3 mb -86.6 300.0 24.0 mm
88% 33.0, -96.8 24.5 °C 15.6 °C 986.8 mb -81.7 310.9 22.9 mm
Destination 33.1, -96.6 24.1 °C 16.0 °C 987.4 mb -91.5 266.6 22.0 mm
Midpoint vertical profile
18-hour forecast · this path · 10 GHz → steady
Propagation score for this path over the next 18 hours. 0 25 50 75 100
Peak 78 at 14:00 UTC · low 70 at 21:00 UTC
Hour-by-hour propagation score for this path — the series plotted above.
Hour UTC Score Rating
08:00 76 GOOD
09:00 75 GOOD
10:00 76 GOOD
11:00 76 GOOD
12:00 77 GOOD
13:00 77 GOOD
14:00 78 GOOD
15:00 75 GOOD
16:00 74 GOOD
17:00 74 GOOD
18:00 77 GOOD
19:00 74 GOOD
20:00 76 GOOD
21:00 70 GOOD
22:00 70 GOOD
23:00 70 GOOD
00:00 71 GOOD
01:00 · now 73 GOOD