EGV-40 CW QRP Transceiver
Page 21
L9 Toroid
L9 is an inductor acting as a collector choke on the TX power amplifier transistor. A FT37-32 is used
(black toroid with an OD of 9.5 mm / 0.375 in). It has 6 turns.
Cut 12 cm (5”) of 0.5 mm enameled wire and wind 6 turns on the black FT37-43 core. Wind the wire
tightly on the core, avoiding loose turns, and spread the turns evenly around the core. They should be
uniformly spread around the circumference of the toroid. Leave pigtails of about 10 mm (0.4”). Remove
the enamel of the pigtails with a cutter prior to soldering the toroid on the board.
The nominal value for L9 is 12.6 µH.
Tuning Polyvaricon capacitor for the VXO CV2/CV3
Install the hardware shaft on the polyvaricon.
Place the Polyvaricon over the board at a distance of 3-5 mm (see picture). This eases the fitting of the
variable cap to the front panel. Do not solder it until you know exactly how you are going to install the
board on the box.
You may want to mount the polyvaricon out of the board. This may be a good idea, but place it as
close as possible and use short and rigid wires. Even small movements may affect the tuning!