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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.

33.5, -98.5 · EM03rm · 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
185.1
km · 115.0 mi
Bearing
104.0°
true · rev 284.0°
Terrain
BLOCKED
117.4 dB diffraction
Propagation
78/100
GOOD
Margin
-58.4
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 volume336 m AGL at the midpoint (1008 m above the chord, 504 m above the 4/3 horizon), so its Fresnel zone (F₁ ≈ 37.3 m) clears with margin. The geometric line of sight is obstructed — buried 551 m below terrain at its worst point.

Great circle
33.538, -98.544 → 33.12, -96.615 · 104.0°
Loss budget · 10 GHz
FSPL (free-space) 157.8 dB
Gaseous (O₂ + H₂O) 1.3 dB
Diffraction 117.4 dB
Rain attenuation 0.0 dB
Total path loss 276.4 dB
Gas rate 0.0070 dB/km · H₂O 0.0000 dB/km/g · O₂ 0.0070 dB/km
Path abs. humidity avg 12.7 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 -276.4 dB
RX antenna gain 30.0 dBi
RX power -198.4 dBm
Sensitivity (CW, 500 Hz) -141.0 dBm
Margin -58.4 dB
Path weather · HRRR average of 9 samples
Temperature
73.6 °F
23.1 °C
Dewpoint
59.4 °F
15.2 °C
T/Td gap
14.2 °F
7.9 °C
Abs. humidity
12.7
g/m³
Pressure
967.3
mb
PWAT
25.7
mm
BL depth
308.1
m AGL
Refrac. gradient
-111.8
N/km · super-refractive
Propagation factors · 10 GHz 78/100
Rain
100 14%
Humidity
90 13%
PWAT
90 11%
Season
68 11%
T-Td Depression
70 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 33.5, -98.5 24.9 °C 12.1 °C 967.3 mb -86.7 325.8 23.3 mm
13% 33.5, -98.3 23.0 °C 12.1 °C 969.5 mb -53.9 315.4 25.3 mm
25% 33.4, -98.1 22.6 °C 15.8 °C 971.7 mb -81.0 327.1 29.2 mm
38% 33.4, -97.8 22.9 °C 16.6 °C 972.5 mb -88.0 332.9 30.2 mm
Midpoint 33.3, -97.6 21.9 °C 16.8 °C 971.2 mb -77.7 271.9 27.8 mm
63% 33.3, -97.3 21.6 °C 18.0 °C 980.7 mb -111.8 315.8 27.0 mm
75% 33.2, -97.1 23.7 °C 14.8 °C 985.8 mb -70.2 338.3 24.0 mm
88% 33.2, -96.9 23.5 °C 15.0 °C 988.3 mb -69.0 279.1 22.7 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 82 at 08:00 UTC · low 65 at 22:00 UTC
Hour-by-hour propagation score for this path — the series plotted above.
Hour UTC Score Rating
08:00 82 EXCELLENT
09:00 76 GOOD
10:00 77 GOOD
11:00 76 GOOD
12:00 78 GOOD
13:00 76 GOOD
14:00 77 GOOD
15:00 77 GOOD
16:00 74 GOOD
17:00 73 GOOD
18:00 80 EXCELLENT
19:00 77 GOOD
20:00 67 GOOD
21:00 67 GOOD
22:00 65 GOOD
23:00 72 GOOD
00:00 67 GOOD
01:00 · now 68 GOOD