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[TowerTalk] Simulation of Mismatched Antennas

To: <towertalk@contesting.com>
Subject: [TowerTalk] Simulation of Mismatched Antennas
From: leewells@lexmark.com (leewells@lexmark.com)
Date: Tue, 1 Sep 1998 14:43:13 -0400
At K5GW's recommendation, I wrote a little program to simulate
line loss, reflections, etc.  The program will print a line each time
the wave travels the length of the line.  It displays the amount of power lost
in the line, and absorbed by the load.  Below are a couple of runs
using Steve Best's numbers from his experiments.  The end values
are almost identical.  If anyone wants the C source code, let me know and
I can provide it.

The programs assumes 100% of the power is reflected at the tuner end.
The reflected power at the antenna is a function of SWR:

power refl coeff = ((SWR-1)/(SWR+1))^2
        

        73 
        --Lee - KT4ZX

===== RUN 1 ======

Input Power: 100.00000 watts     SWR 1.32000 : 1     Line loss: 1.64000 db
Power Reflection Coeffecient (antenna to line) =     0.01902
Line loss coeffecient =     0.31451

Iter   direction     loss pwr      xfer_pwr     refl_pwr     total_xfer    
total_loss
   1   to Ant        31.45118      67.24468      1.30414       67.24468      
31.45118
   2   to Xmit        0.41017                    0.89397       67.24468      
31.86134
   3   to Ant         0.28116       0.60115      0.01166       67.84583      
32.14251
   4   to Xmit        0.00367                    0.00799       67.84583      
32.14618
   5   to Ant         0.00251       0.00537      0.00010       67.85121      
32.14869
   6   to Xmit        0.00003                    0.00007       67.85121      
32.14872
   7   to Ant         0.00002       0.00005      0.00000       67.85125      
32.14874
   8   to Xmit        0.00000                    0.00000       67.85125      
32.14875
   9   to Ant         0.00000       0.00000      0.00000       67.85125      
32.14875
  10   to Xmit        0.00000                    0.00000       67.85125      
32.14875

Total power delivered to antenna is    67.85125 watts
Total power lost in line is    32.14875 watts


==================

===== RUN 2 ======

Input Power: 100.00000 watts     SWR 8.74000 : 1     Line loss: 1.64000 db
Power Reflection Coeffecient (antenna to line) =     0.63149
Line loss coeffecient =     0.31451

Iter   direction     loss pwr      xfer_pwr     refl_pwr     total_xfer    
total_loss
   1   to Ant        31.45118      25.26117     43.28765       25.26117      
31.45118
   2   to Xmit       13.61448                   29.67317       25.26117      
45.06565
   3   to Ant         9.33256       7.49579     12.84482       32.75696      
54.39822
   4   to Xmit        4.03985                    8.80497       32.75696      
58.43806
   5   to Ant         2.76927       2.22424      3.81147       34.98120      
61.20733
   6   to Xmit        1.19875                    2.61271       34.98120      
62.40608
   7   to Ant         0.82173       0.66000      1.13098       35.64121      
63.22781
   8   to Xmit        0.35571                    0.77528       35.64121      
63.58352
<snip>
  36   to Xmit        0.00000                    0.00000       35.91968      
64.08032

Total power delivered to antenna is    35.91968 watts
Total power lost in line is    64.08032 watts


==================

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