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K0IMH

Joined: Wed, Aug 16th 2006, 14:17 Roles: N/A Moderates: N/A

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Simulate 1/4 wave line with L and C Sep 11th 2023, 10:47 1 846 on 11/9/23

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Simulate 1/4 wave line with L and C K0IMH on 11/9/23
Several websites give a prescription for using an LC network in place of a 1/4 wave line for impedance matching. I am trying to simulate this using CircuitLab and I cannot get it to work. I even looked up the original 1943 IEEE paper that gave the prescription.
So I assume 50 ohm cable and try e.g. input 25 ohms and output 100 ohms or input 10 ohms and output 250 ohms. At 5.75 MHz the capacitors for 50 ohms are 555 pf and the inductors are 1.38 uH.
My criteria for success are A) conservation of energy- V squared/R at each end is equal or else B) two of the networks back to back should make a half wave with equal input and output voltages.
What I find is that in either case the output voltages are way too low, e.g. factor of 2 or 3.
I tried a couple of sources A) AC current source across 25 ohm to ground. B) AC voltage source with divider 10 K and 25 ohms so back reflections see the 25 ohms.
Any help appreciated. David, K0IMH

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