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Old March 14th 10, 02:34 PM posted to rec.radio.amateur.antenna
JC[_3_] JC[_3_] is offline
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First recorded activity by RadioBanter: May 2008
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Default Lossy Coax: how is energy lost ?

Thanks to all for your explanations, I now have a much better understanding
of the energy dissipation in a coax.
73 - JC

"JC" a écrit dans le message de news:
...
In a lossy coax the lost energy is, I suppose, heating up the dielectric.
To try to visualize that I stripped off 30 cm of dielectric from an old
RG58 cable and put it in a 900 W 2450 MHz standard microwave oven together
with a 100cc cup of water as dummy load.
2 minutes after switching on the water was boiling but the polyethylene
was only slightly warmer due to the proximity to the boiling water., Can
I conclude that RG58 dielectric has no loss at 2350 MHz ?
Certainly not ( it is well known that all the PE food containers used in
such ovens are not heated ), but what is wrong in this test ? how does it
differ from the dielectric heated in an actual operating lossy cable ?
JC