woensdag 20 november 2019

Dual band matching networks for VHF endfed vertical antennas

Recently I succeeded in designing a dual band matching network for a 70 and 144 Mhz 1/2 wave endfed vertical.
On both bands the impedance is high. About 300 ohm on 2m and 600 ohm on 4 meter band.

After this, I decided to design networks for a 28 + 50 vertical with trap.

I used the Smith chart program of Prof. Fritz Dellsperger.

Here are some results;

28 + 50 Mhz, both transformed from 50 to 800 ohm












28 + 50 Mhz, both transformed from 50 to 200 ohm












28 + 50 Mhz, both transformed from 200 to 800 ohm













50 + 70 Mhz, both transformed from 50 to 500 ohm















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