Antenna tunning circuit for 27MHz CB band

Hosted circuit

The antenna tunning circuit can accommodate 1/2 wave length antennas or higher, for input resistances of 50 Ohms which make it suitable for CB (Citizen Band) transceivers. C1 is for fine tunning and C2 is just for tunning. Turning C3 with the help of C2 you can set the SWR to 1:1. The Coil L is made of 11 turns of insulated copper wire with diameter of 1mm.

If you use 1/2 wave length antenna (5.5m) then C3 has to be set to highest capacitance. The connection with the receiver can be done using the SO-239 connector (UHF) or with BNC's. Keep the distance of the cable between the transceiver and the tunning cir

Comments

simple wrote on Aug 13, 2007

A balun is better so as not to mess up the pattern

Jean wrote on Sep 12, 2007

I am trying to build a mobile antenna that runs on the 27MHz frequency. The whip length is 0.980m, what i would need help on is the coil and the cap sizes, The coil diameter is 1.25cm, and the coil insulator length is 4cm long.

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