[Amps] 2 x 8877

TexasRF at aol.com TexasRF at aol.com
Tue Mar 2 12:20:09 EST 2004


Whoa, wait a minute! That 150cm by 100 cm opening might be a waveguide beyond 
cutoff but the attenuation for this size opening is pretty low according to 
the Bill Orr Radio Handbook.

The chart for this size opening shows a constant attenuation from about 
1000mhz and lower frequencies on the order of 8db per inch. If the metal is .125 
inches thick then the attenuation is on the order of only one db!

When the opening is reduced to .125 inches the attenuation is on the order of 
124 db per inch from about 2000mhz and down. With that level of attenuation a 
.125 inch thick screen would have about 30db of through loss.

Cutoff means there is signal attenuation, not a total loss of transmission.

73 de K5GW


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