# This lr.py input file recreates Figure 5 in "A Guide to the Use
# of the ITS Irregular Terrain Model in the Area Prediction Mode," G.A.
# Hufford, A.G. Longley, W.A. Kissick, 1982, NTIA report 82-100.
#
# Mike Markowski, mike.ab3ap@gmail.com
# May 2023

# Copied from the report, Section 7.1, Table 5:
# Frequency                              45 MHz
# Polarization                            Vertical
# Antenna heights                         2 m
#
# Transmitter power                      16 dBW
# Antenna gains                          -3 dBi
# Line losses                             1 dB
#
# kTB (B=25 kHz)                       -160 dBW
# Rural noise, above kTB                 21 dB
# Margin for multipath (Rayleigh) fading  6 dB
# Margin for uncertainties                7 dB
#
# Required (rf) signal-to-noise ratio     6 dB
#
# Signal: 16 dBw + 2(-3 dBi - 1 dB) = 8 dBw
# Noise:  -160 dBw + 21 dB + 6 dB + 7 dB = -126 dBW
# Without path loss, S/N = 134 dB
# With required S/N 6 dB, acceptable loss = 134-6 = 128 dB
#
# Results are obtained by running: lr.py < mobile.lr
# Since worst case loss is 128 dB, locate 128 in each column of output
# and use linear interpolation to create Table 6 in the report.

title Operational Ranges for a Mobile-to-Mobile System
modeVar 0    # First try success service.
deltaH 90    # m, terrain roughness factor.
dist 1 9 1   # m, start stop delta of distance column output.
dist 10 30 5 # m, start stop delta
epsilon 15   # F/m, relative ground permittivity.
freq 45      # MHz, frequency.
hgtRx 2      # m, receive antenna height above surface.
hgtTx 2      # m, transmit antenna height above surface.
N0 301       # N-units, sea level refractivity.
pol v        # v or h
qSit 95 90 80 70 50 20 10 # Percent, confidence levels.
sigma 0.005  # S/m, relative ground conductivity.
sitingRx r   # r, c or v, receive station siting.
sitingTx r   # r(andom), c(areful) or v(ery careful), tx station siting.
run area     # ITM area mode run.