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ANTENTOP- 01- 2009, # 011

QRPP/QRP Transceiver by UB5UG






By: Yuri Medinets, UB5UG, Kiev


Credit Line: Radio #1, 1984, p.24


The transceiver is designed for the 10-meters Band. Schematic of this simple and reliable transceiver is shown on Figure 1.



Transceiver consists of the RF generator on VT1 (RX/TX), mixer on VD3 (RX) and audio amplifier on VT2 and VT3 (RX).





Figure 1 Transceiver by UB5UG



RX Mode: RF voltage at L1 is limited by VD1and VD2 up to a level of 0.3-V. The level (0.3-V) is chosen by amplitude of the second harmonic (that selected with L2L3C3). The amplitude should be sufficient for good job of the mixer on VD3.


TX Mode: Diodes VD1 and VD3 are electrically unplugged from L1C9. RF voltage is maximum across L1. TX gives full power into L2L3C3 and then into antenna. Frequency of the generator differs (because VD1 and VD3) at RX/TX on several hundreds Hz, that is needed transceiver mode. One Transistor quartz generator may provide up to 50-mWts. Simple Push-Pull PA may increase the transceiver power up to 1-Wtts (and convert QRPP to QRP). Figure 2 shows schematic for the PA. C2 and L2 do not use at the configuration.



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