The Ground Tuning Unit (GTU)

Parts List

R1 Variable resistor 50k/ohm

S1 Switch single pole 12 way

C1 Capacitor variable 500pf air spaced (1mm recommended)

C2 Capacitor 10nF (103)

D1 Diode point contact germanium diode 1N34 OA91

L1 Toroid T50-2 ,

M1 Meter 50 or 100ma,

Enamelled copper wire 1.8 or 2mm (14swg) and 0.5mm(24swg),

Insulated shaft extension

Why build a ground tuner?

The conductivity of your ground varies from one location to the next.

This is particularly important to the portable radio station.

If you are using a vertical or end fed antenna, a good low resistance ground is required for efficient operation.

The GTU enables you to tune your antenna against this ground, often shown illustrated as a dotted line which represents the missing half of the earth side of the dipole.