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ANTENTOP- 01- 2006, # 008

Experimental CW QRP Transceiver



Receiver. DA1 is mixer. Quartz filter is a 3- quartz filter. I am not to do selection of quartz for using it in the filter (of course, if you have possibility to do the selection- do it). All forms for coils are from old ex- USSR VHF FM Transceiver Len.

DA2 is used as a CW detector and oscillator on 10700 kHz. . The frequency of generation is lowered up to required with the help of RFC and L switched in serial. Audio amplifier, which is shown on Figure 3, is implemented with a low noise transistor and LM386N.

Figure 5 Electronic Switch

Transmitter: L5 (3 turn)/L6 (10 turn) are coiled on a ferrite ring, international analog FT- 37-63, by 0.3 mm wire (28 AWG). Each coil is sitting on its half of the ring. L3 5 turns wire in 0.5 mm or 24 AWG) is coiled on a form in diameter of 7 mm.

VFO: Figure 4 shows the VFO. This one is borrowed by me from DC Receiver for the 20 meters by B. Stepanov, (RU3AX). However I added a frequencies shift (VT2). This one needed for SSB/CW QSO. VFO coil is wound on a ceramic form in diameter of 10 mm and contained 45 turns. All capacitors are high quality ones.

Electronic switch: Figure 5 shows the Switch. Borrowed from Ukraine radio magazine Radio- Hobby # 1, 2000.

PSB: I did not design a PSB for the transceiver. I did it by ugly montage. Each block is mounted on the own board. Fully assembled and tuned boards are soldered at corners to transceiver case.

Adjustment and Tuning: Nothing special at tuning the unit. Do adjustment from Audio Amplifier, then Receiver and Transmitter.


Commentary to VFO Board:

KT315, KT361- Low Power RF Transistor, 250 MHz,

300 mW

K303E Low Power RF FET Transistor

VD1 Zener Diode, 5V

VD2 Varicap, 10- 30 pF


Commentary to Main Board:

174C1 = NE602, NE612

K510 = High Speed RF Switch Diode

KT606 = RF Power Transistor, 300 MHz, 1 W

KT922B- RF Power Transistor, 300 MHz, 10 W

= micro Henry

K303E Low Power RF FET Transistor

0B= 0 V

12 B= 12 V


Commentary to Switch Board:

KT209 400 mW Switch Transistor

311 Germanium Diode



Transceiver Mosquito 20m

Page 60




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February 11, 2018 0:02

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