[ARC5] Smart People: Antenna Matching Mystery

[David Stinson]

OK y'all- here's a mystery (at least to me),

Series circuit, designed to match a normally 5-12 Ohm

Aircraft radio output to resistive 50 Ohms.

Follow me here:

 

Series circuit:

PA Tank coupling link - Roller coil -

120pFd ceramic cap mounted at antenna post - 

50 Ohm Load = 25 W out.

 

PA Tank coupling coil -  120pFd ceramic cap mounted

at the input of the Roller Coil - Roller Coil -

50 Ohm Load = 15W out.

 

The ceramic cap is near chassis ground both ways,

so it's not circulation currents.

The PA tuning cap setting does not change,

so it's not de-tuning the PA tank. 

 

Why the difference between these two series circuits?

 

73 Dave AB5S

 

 

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