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Simple QRP CW Transceiver for the 20 meters

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ANTENTOP- 01- 2005, # 007

Simple QRP CW Transceiver for the 20 meters

 

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)

 

DATA:

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)

 

DESCRIPTION:

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.

Transceiver can work without a quartz if you go connections shown in dotted line. Of course, the frequency would be nonstable.

 

PARTS:

L1- 9 turns, wire 1 mm (18 AWG), diameter 10 mm, inductance 0.5 micro Henry.

L2-25 turns on Soviet Resistor MLT- 1, wire 0.2 mm (30 AWG), inductance 3 micro Henry;

L3-60 turns, wire 0.1 mm (38 AWG), diameter 3 mm, inductance 7 micro Henry.

RFC- inductance 10 micro Henry.

 

Transceiver was assembled in a box from TV tuner.

References: Polyakov V.T. : To the Ham about the DC Technique. Moscow, 1990.

 

 

 

Cable with Connector. Figure from the original manual.

Was reproduced at U- QRP- C. Reference Book- #3

 

 

http://www.antentop.org/

Page 68

 

67 68 69

 

 

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August 3, 2016 16:49

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