1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
15.000 ; Earth Dielectric Constant (Relative permittivity)
0.005 ; Earth Conductivity (Siemens per meter)
301.000 ; Atmospheric Bending Constant (N-units)
300.000 ; Frequency in MHz (20 MHz to 20 GHz)
5 ; Radio Climate (5 = Continental Temperate)
0 ; Polarization (0 = Horizontal, 1 = Vertical)
0.5 ; Fraction of situations (50% of locations)
0.5 ; Fraction of time (50% of the time)
This file contains Longley-Rice path loss parameters used
by SPLAT! Anything after the 8th line is ignored by the
program. Comments are allowed following each element of
numeric data. No blank lines are allowed at the top.
Earth dielectric constants and conductivity values are as follows:
Dielectric Constant Conductivity
Salt water : 80 5.000
Good ground : 25 0.020
Fresh water : 80 0.010
Marshy land : 12 0.007
Farmland, forest : 15 0.005
Average ground : 15 0.005
Mountain, sand : 13 0.002
City : 5 0.001
Poor ground : 4 0.001
Radio climate codes are defined as follows:
1: Equatorial (Congo)
2: Continental Subtropical (Sudan)
3: Maritime Subtropical (West coast of Africa)
4: Desert (Sahara)
5: Continental Temperate
6: Maritime Temperate, over land (UK and west coasts of US & EU)
7: Maritime Temperate, over sea
The Continental Temperate climate (5) is common to large land masses in
the temperate zone, such as the United States. For paths shorter than
100 km, there is little difference between Continental and Martitime
Temperate climates.
The final two parameters in the .lrp file correspond to the statistical
analysis provided by the Longley-Rice model. In this example, SPLAT!
will return the maximum path loss occurring 50% of the time (fraction
of time) in 50% of situations (fraction of situations). Use a fraction
of time of 0.97 for digital television, 0.50 for analog. Isotropic
antennas are assumed. A tuned half-wave dipole has a gain of 2.14 dB
above that of an isotropic antenna.
Edit these parameters as required and save the result ("Save As")
to a filename with an extension of ".lrp" in the directory normally
used for .qth files (current working directory is assumed). The
base of the filename MUST match the base of the corresponding
SPLAT! transmitter site QTH filename for proper correlation
between data sets. In other words:
wnjt.qth <--- TX site data for WNJT
wnjt.lrp <--- Corresponding Longly-Rice parameters for WNJT
If an LRP file corresponding to the tx_site QTH file cannot be
found, SPLAT! scans the current working directory for "splat.lrp".
If this file cannot be found, then the default parameters listed
above are assigned by SPLAT!, and a "splat.lrp" file containing
these parameters is written to the current working directory.
For further information on Longley-Rice model parameters, see:
http://elbert.its.bldrdoc.gov/itm.html
http://www.softwright.com/faq/engineering/prop_longley_rice.html
Also consult SPLAT!'s documentation for more information.
|
