CW Transceiver 20- Meters
( See schematic on the page
68. Schematic is from the original manual. Was reproduced at “U- QRP- C. Reference Book- #3)
RF Power: near 1 watt at 24 V.
Range of Feeding Voltage: 18- 24 Volts
Antenna impedance: 75 Ohms (can be any desirable)
Quartz Stabilization Frequency.
Shift TX/RX: 400… 700 Hz.
VXO: 3… 6 kHz (depends on used quartz)
RX MODE: T1 is mixer. Used power RF MOS transistor,
3 Watts, 250 MHz.. T2 is oscillator,
the same as 2N2222. Operational amplifier any available. Here
used with gain 100,000.
TX MODE: Relay P1 turns T1 to TX mode. Parts R12, C16,
D1 do frequency shift on 400… 700 Hz (depends on used quartz).
It is possible to use quartz both as on 7 as on 14 MHz. T1 is
installed on a small heater sink, so long duty TX mode available.
I did tuning
of the L1C1C2C3 to match 75 Ohm coaxial,
however, it is possible to tune this one on any load in the range
of 50- 300 Ohms by C1C2C3.
can work without a quartz if you go connections
shown in dotted line. Of course, the frequency would be nonstable.
L1- 9 turns,
wire 1 mm (18 AWG), diameter 10 mm, inductance 0.5 micro Henry.
on Soviet Resistor MLT- 1, wire 0.2 mm (30 AWG), inductance 3
wire 0.1 mm (38 AWG), diameter 3 mm, inductance 7 micro
10 micro Henry.
was assembled in a box from TV tuner.
References: Polyakov V.T. : To the Ham
about the DC Technique. Moscow,