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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

33.1, -96.6 · EM13qc · 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
235.6
km · 146.4 mi
Bearing
37.9°
true · rev 217.9°
Terrain
BLOCKED
123.2 dB diffraction
Propagation
74/100
GOOD
Margin
-66.8
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 volume545 m AGL at the midpoint (1634 m above the chord, 817 m above the 4/3 horizon), so its Fresnel zone (F₁ ≈ 42.0 m) clears with margin. The geometric line of sight is obstructed — buried 773 m below terrain at its worst point.

Great circle
31.457, -98.168 → 33.12, -96.615 · 37.9°
Loss budget · 10 GHz
FSPL (free-space) 159.9 dB
Gaseous (O₂ + H₂O) 1.6 dB
Diffraction 123.2 dB
Rain attenuation 0.0 dB
Total path loss 284.8 dB
Gas rate 0.0070 dB/km · H₂O 0.0000 dB/km/g · O₂ 0.0070 dB/km
Path abs. humidity avg 15.8 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 -284.8 dB
RX antenna gain 30.0 dBi
RX power -206.8 dBm
Sensitivity (CW, 500 Hz) -141.0 dBm
Margin -66.8 dB
Path weather · HRRR average of 9 samples
Temperature
77.6 °F
25.3 °C
Dewpoint
65.9 °F
18.8 °C
T/Td gap
11.7 °F
6.5 °C
Abs. humidity
15.8
g/m³
Pressure
969.5
mb
PWAT
39.2
mm
BL depth
855.4
m AGL
Refrac. gradient
-73.4
N/km
Propagation factors · 10 GHz 74/100
Rain
100 14%
Humidity
95 13%
PWAT
70 11%
Season
68 11%
T-Td Depression
85 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, -97.8 29.4 °C 19.3 °C 978.2 mb -55.7 1571.7 40.1 mm
38% 32.1, -97.6 25.8 °C 19.3 °C 985.8 mb -50.4 570.8 43.1 mm
Midpoint 32.3, -97.4 25.8 °C 19.0 °C 988.3 mb -51.0 551.0 39.7 mm
63% 32.5, -97.2 24.1 °C 17.9 °C 987.9 mb -48.9 463.3 37.8 mm
75% 32.7, -97.0 23.7 °C 17.9 °C 999.8 mb -52.6 656.0 41.6 mm
88% 32.9, -96.8 20.7 °C 17.6 °C 998.3 mb -73.4 433.5 37.3 mm
Destination 33.1, -96.6 19.4 °C 17.8 °C 995.0 mb -62.2 456.2 40.3 mm
Midpoint vertical profile
17-hour forecast · this path · 10 GHz → steady
Propagation score for this path over the next 17 hours. 0 25 50 75 100
Peak 74 at 03:00 UTC · low 69 at 00:00 UTC
Hour-by-hour propagation score for this path — the series plotted above.
Hour UTC Score Rating
21:00 71 GOOD
22:00 70 GOOD
23:00 70 GOOD
00:00 69 GOOD
01:00 70 GOOD
02:00 70 GOOD
03:00 74 GOOD
04:00 72 GOOD
05:00 72 GOOD
06:00 72 GOOD
07:00 71 GOOD
08:00 71 GOOD
09:00 71 GOOD
10:00 72 GOOD
11:00 71 GOOD
12:00 72 GOOD
13:00 · now 73 GOOD