It is a variant of a simple DC transceiver. Transistor
of PA works like a mixer in receiving mode. So, there is no any
commutation in the RF circuits. The transceiver has output power
0.35- Wtts, shift TX/RX- 400-Hz, RX sensitivity 2 microV. Power
voltage is 15-V, current at RX/TX – 30/120-mA.
1 shows schematic of the transceiver. VFO
is made on V2. C6C7L4C8C9C10 is tuned on 14-MHz. L3C4 is tuned
on 28- MHz. When key (connected to X2) is “down” (TX-
mode) relay K1 provides plus 15-V onto transistor V1. At RX mode
the transistor works like a mixer. Audio signal (at RX-mode) goes
through filter C3L5C11 (3- kHz cutoff frequency)
onto audio amplifier made on V4,V5,V6
(amplification factor more the 10000). High-Ohmic headphones (3-
4-kOhm at DC, old military ones) are used with the amplifier.
The phones are connected to X3. Low Ohmic phones does not work good with the amplifier.
Inductor L4 has 18 turns of wire in 0.6-mm (23-AWG) diameter, winding
length is 12- mm, coiled on a form of 8-mm diameter. L3 has 9
turns of wire in 0.25- mm (30- AWG) diameter, coiled on a ferrite
ring 10 –mm OD x 5- mm ID x- 10- mm- H with permeability 50, tap
made from 6-turn from “cold” end. L2 has 3 turns of wire in 0.25-
mm (30- AWG) diameter, coiled above L3. Inductor L1 has 10 turns
of wire in 0.6-mm (23-AWG) diameter, winding length is 14- mm,
coiled on a form of 10-mm diameter, tap made from 3-turn from
“cold” end. L5 has inductance 0.15- H. It is possible to use collector’s
coil from an output transformer from any transistor radio.
Credit Line: V. Polyakov. Transivery pryamogo
preobrazovania, Moscow, DOSAAF, 1984
Moscow, P.H.: DOSAAF, 1984)