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Old December 7th 07, 06:00 PM posted to rec.radio.amateur.antenna
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Default Loading Coils; was : Vincent antenna

Keith Dysart wrote:
If the 100 ohm line was only 5 degrees long, how
long would the 600 ohm line have to be to obtain
0 ohms at the input?


-jcot(5) = -j11.43 normalized to Z0=100 ohms

-j100(11.43) = -j1143 ohms at the junction

-j1143/600 = -j1.905 normalized to Z0=600 ohms

arctan(1.905) = 62.3 degrees of Z0=600 ohm line

Would the phase shift at the junction still be
36.6 degrees?


The new phase shift would be 90-5-62.3 = 22.7 deg.

62.3 + 5 + 22.7 = 90 degrees

This example would correspond to a larger coil and
a shorter stinger in a loaded mobile antenna.
--
73, Cecil http://www.w5dxp.com
 
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