Classical Antenna Tuner (with two capacitors – one for matching
with transmitter another one do matching with load and inductors
that value depends on frequency between the capacitors) is
known by hams and served at the ham shack for decades. Schematic
of the Classical Antenna Tuner is shown on Figure 1. This tuner can do match from 80 to 10-
Note from I.G.: There are lots commercial design (MFJ may
be a leader in that) of such Tuner that can stand power from several
tens watts to several kilo watts. At almost any hamfest
it is possible find lots home brew designs of the tuner. It is
only confirms high working function of the ATU.
Inductor L1 has 35 turns of copper wire in
diameter 1.2- 1.5- mm (17- 14 AWG). The inductor is wound on form
in diameter of 40- mm gap between turns is 2- mm. Taps made (from
cold end) from 12, 15, 18, 21, 24, 27, 29, 31, 33 and 35 turns.
L2 has 3 turns made by the same wire on a form in 25 mm diameter
and has 20- mm length.
C1 and C2 were used from an old military VHF radio. Gap between
plates is near 1- mm. It was used capacitors with 160- pF maxima
tuner was used with FT-897D HF Transceiver. Matching with antenna was done with help of internal
SWR meter of the transceiver.