This JavaScript program evaluates the performance of an antenna system, computing the consequences of SWR and feedline loss.

original program concept done in CPM basic by KC6A and N6NB


forward power from transmitter in watts -1VSWR @ transmitter
feed line loss in db( must be in line with other values)  Enter 2.2 for dipoles; add 2.2 for antennas rated in dBd 
Enter operating frequency in mHz 1.8mHz to 2450mHz  

reverse power at transmitter -1VSWR @ antenna
forward power in watts at antenna reflected power in watts from the antenna
true power in watts into antenna power in watts lost in feed line
db line loss including EIRP in watts power in watts off the antenna

Coax Cable Signal Loss (Attenuation) in dB per 100ft aprox

Loss RG-174 RG-8 RG-8X RG-213 RG-6 RG-11 RF-9914 RF-9913 LMR-1200 LMR-900 LMR-600 1/2” Superflex
1MHz 1.9dB   0.5dB 0.2dB 0.2dB 0.2dB 0.3dB 0.2dB,        
10MHz  3.3dB  



0.6db  0.4db   0.5db  0.4db        
30MHz                  0.2db


 0.42db  0.56db
 50MHz 6.6db  1.2db  2.5db  1.6db  1.4db  1.0db  1.1db  0.9db  0.27db  0.37db  0.55db  0.73db 
100MHz  8.9db  1.5db  3.6db   2.2db 2.0db  1.6db  1.5db  1.4db  0.4db  0.6db  0.92db  1.1db 
200MHz  11.9db  1.8db  5.4db  3.3db  2.8db  2.3db  2.0db  1.8db  0.58db  0.78db  1.1db  1.5db 
400MHz  17.3db  2.5db  7.9db  4.8db  4.3db  3.5db  2.9db  2.6db  0.80db  1.1db  1.45db  2.3db 
700MHz  26.0db  3.25db  11.0db  6.6db  5.6db  4.7db  3.8db  3.6db         
900MHz 27.9db  3.9db  12.6db  7.7db  6.0db  5.4db  4.9db  4.2db  1.27db  1.7db  2.5db  3.41db 
1GHz 32.0db  4.4db  13.5db  8.3db  6.1db  5.6db  5.3db  4.5db  1.40db  2.0db  3.0db  4.4db 


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