S- Tuner provides matching of asymmetrical output of a transceiver with
symmetrical feeder line. Symmetrical feeder line (as usual it
is two- wire ladder line or two- wire line with plastic insulation)
used to feed symmetrical dipole antennas.
Lots additional stuff on S- Tuner it is possible to find from the site
Figure 1 shows schematic of the S-Tuner.
transformer (made on ferrite tubes used on the monitor cable)
forms symmetrical output. Variable capacitor and tap inductor
provide matching two- wire line feeder with transmitter. Figure 2 shows design of the S- Tuner.
used at the tuner has capacity 12x520- pF.
At the lower HF-Bands it may be need to connect to bridge to the
variable capacitor a fixed capacitor on 500- pF or 1000- pF. It is possible to use a two or four section
variable capacitor from an old tube receiver. At the case rotors should be connected to
binocular transformer stator should be connected to the “ground.”
Such capacitor works fine up to 100- Wtts.
S-Tuner it is used a tap- inductor on ferrite connected in serial with air –
winded inductor. Air winded inductor is used at upper HF- Bands.
The air winded inductor contained 4 turns of copper wire in diameter
1.3- mm (16- AWG). Inductor is coiled on a form in diameter 10-
mm. Then it is stretched to 6-10 millimeter (should check by experimental)
in length. Tap inductor is coiled on ferrite ring Amidon ̉200-2. The inductor
has inductance in 40- microHenry. Figure 3
shows the inductor. Inductor has 15 taps. Tap # 1, 2, 3 made from
each turn. Tap # 4, 6 made from each second turn. Tap # 7, 8 made
from each third turn. Tap # 9 from fourth turn. Then taps spaced
evenly among the rest taps. It is possible to use at the S- Tuner
almost any tapped inductor with overall inductance up to 34- microHenry.