In their catalog (Catalog TL-10), Times Microwave Systems, Inc. provides
data on the actual leakage of various shields. Unfortunately, their data
only go down to 10 MHz, but at that frequency, shield made of a single
copper shield (95%) radiates a power that is about 50 dB down from the
signal level in the cable per foot of cable. Double braid is down about
98 dB per foot and solid sheath (hardline) is down nearly 300 dB per
foot. The curves are nearly flat for the braided shields out to about
100 MHz then increase about 10 dB per foot by 1 GHz.
They don't go into detail on how these numbers were found except to say
that the data for the braided cables were obtained through measurment
and the data for the hardline are theoretical.
John
KC4ZXX
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