>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.
** My guess is that, at 28MHz, the radiation from the antenna is at
least 30db stronger than that from the window. .
>
>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
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|