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Old June 11th 10, 03:38 PM posted to rec.radio.amateur.antenna
K1TTT K1TTT is offline
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First recorded activity by RadioBanter: Apr 2010
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Default Where does it go? (mismatched power)

On Jun 11, 10:45*am, K1TTT wrote:
On Jun 9, 10:38*pm, Jim Lux wrote:



In fact, the ration between that stored energy and the amount flowing
"through" (i.e. radiated away) is related to the directivity of the
antenna: high directivity antennas have high stored energy (large
magnetic and electric fields): *the ratio of stored to radiated energy
is "antenna Q" (analogous to the stored energy in a LC circuit leading
to resonant rise).


So, high directivity = high stored energy = high circulating energy =
high I2R losses.


this is a relationship i haven't heard of before... and would be very
wary of stating so simply. *it may be true for a specific type of
antenna, MAYBE Yagi's, MAYBE rhombics or or close coupled wire arrays,
but some of the most directive antennas are parabolic dishes which i
would expect to have very low Q and extremely low losses. *you could
also have an antenna with very high Q, very high i^2r losses, but very
low directivity, so i would be careful about drawing a direct link
between the two.


and yes, this does work for complex loads and multiple stubs and
connections to the line.

this is a reasonable description of the derivation of these
techniques, study especially the Thevenin equivalent impedance
representation on page 2-13 and how it is applied:
http://ee.sharif.edu/~comcir/readings/tran%20line.pdf