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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.

31.5, -98.2 · EM01vk · 8.0 ft AGL

33.2, -96.5 · EM13se · 30.0 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 21:00z · 9/9 path points
Distance
251.2
km · 156.1 mi
Bearing
39.5°
true · rev 219.5°
Terrain
BLOCKED
137.5 dB diffraction
Propagation
55/100
MARGINAL
Margin
-100.5
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 volume ≈ 619 m AGL at the midpoint (1858 m above the chord, 929 m above the 4/3 horizon), so its Fresnel zone (F₁ ≈ 28.0 m) clears with margin. The geometric line of sight is obstructed — buried 882 m below terrain at its worst point.

Great circle
31.457, -98.168 → 33.189, -96.452 · 39.5°
Loss budget · 24 GHz
FSPL (free-space) 168.0 dB
Gaseous (O₂ + H₂O) 13.0 dB
Diffraction 137.5 dB
Rain attenuation 0.0 dB
Total path loss 318.5 dB
Gas rate 0.0519 dB/km · H₂O 0.0020 dB/km/g · O₂ 0.0200 dB/km
Path abs. humidity avg 15.9 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 -318.5 dB
RX antenna gain 30.0 dBi
RX power -240.5 dBm
Sensitivity (CW, 500 Hz) -141.0 dBm
Margin -100.5 dB
Path weather · HRRR average of 9 samples
Temperature
77.3 °F
25.2 °C
Dewpoint
66.1 °F
19.0 °C
T/Td gap
11.2 °F
6.2 °C
Abs. humidity
15.9
g/m³
Pressure
969.5
mb
PWAT
39.0
mm
BL depth
871.9
m AGL
Refrac. gradient
-72.4
N/km
Propagation factors · 24 GHz 55/100
Rain
100 14%
Humidity
0 13%
PWAT
35 11%
Season
47 11%
T-Td Depression
60 10%
Refractivity
55 10%
Pressure
88 10%
Sky Cover
50 8%
Wind
50 8%
Time of Day
18 4%
Atmospheric profile HRRR 3 km Valid 2026-05-10 21:00 UTC · 9 samples
Point Lat, lon Temp Dewpt Press dN/dh BL m PWAT Duct
Source 31.5, -98.2 29.5 °C 20.9 °C 969.5 mb -72.4 1526.8 36.1 mm —
13% 31.7, -98.0 29.6 °C 19.9 °C 973.2 mb -65.2 1469.0 36.7 mm —
25% 31.9, -97.7 29.4 °C 19.3 °C 978.2 mb -55.7 1571.7 40.1 mm —
38% 32.1, -97.5 26.9 °C 19.8 °C 993.0 mb -46.9 730.8 42.3 mm —
Midpoint 32.3, -97.3 24.6 °C 18.4 °C 988.6 mb -52.3 493.0 38.8 mm —
63% 32.5, -97.1 24.3 °C 18.6 °C 993.5 mb -48.7 511.9 38.7 mm —
75% 32.8, -96.9 22.4 °C 17.9 °C 997.1 mb -59.1 505.2 38.6 mm —
88% 33.0, -96.7 19.7 °C 18.0 °C 998.0 mb -71.9 438.2 38.7 mm —
Destination 33.2, -96.5 20.1 °C 17.9 °C 997.2 mb -58.9 600.2 41.5 mm —
Midpoint vertical profile
17-hour forecast · this path · 24 GHz → steady
Propagation score for this path over the next 17 hours. 0 25 50 75 100
Peak 63 at 13:00 UTC · low 50 at 00:00 UTC
Hour-by-hour propagation score for this path — the series plotted above.
Hour UTC Score Rating
21:00 55 MARGINAL
22:00 51 MARGINAL
23:00 53 MARGINAL
00:00 50 MARGINAL
01:00 51 MARGINAL
02:00 50 MARGINAL
03:00 56 MARGINAL
04:00 54 MARGINAL
05:00 55 MARGINAL
06:00 53 MARGINAL
07:00 54 MARGINAL
08:00 55 MARGINAL
09:00 55 MARGINAL
10:00 54 MARGINAL
11:00 56 MARGINAL
12:00 57 MARGINAL
13:00 · now 63 MARGINAL