| The first winding of my transformer is contained 3
turns and the second has 30 turns. The first winding is wound with
wire from L1 coil. The second winding is wound with wire of 0.3
mm (#27-#25 AWG). However the second wire is depend on the design
of the coupling transformer, RF power going in to the antenna and
for characteristics of the LED. Design of the ATU is shown in Figure 13. The front view is shown in Figure 14.
The coil wound on the mustard jar L1 is fastened to
the case of the ATU using the metal cap as the base mount. From
L1 the tap wires go to the switches. It is necessary to keep the
length of the wires going to the switches as short as possible.
Figure 13 Design of Simple ATU
| The capacitor C1 is behind the switch and its calibration
is located on the front panel. Because the capacitor has a short in length adjusting
shaft, it was lengthened with help of an old ballpoint pen.
Universal ATU for the HF Bands, Radiolubitel
KV and UKV, October 1999, p. 29
Universal ATU for the HF Bands, Radiolubitel,
November 1993, p. 43
Antennas: Tuning and Adjustment, Radiosoft,
Moscow 2002,270 pages.
 Peter Linsley (G3PDL) : HF SINGLE COIL "Z-MATCH" ATU // SPRAT p.76.
Figure 14 Front View of Simple ATU