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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