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o Why QRP?

o QRP Contests by YU1LM/QRP

o Homebrew

o Classification SDR projects

          o  YU1LM SDR clasification

o DC (direct conversion) receivers

           o  DC RX-YU1LM Serbian

           o  DC RX-YU1LM English

o DC (direct conversion) transmitters

            o Audio phase shift networks

o Filters

            o Tunable crystal filter

            o Tunable HF BP 2-30 MHz

            o Band pass 1.8 MHz

            o Band pass 50 MHz

            o Band pass 144 MHz           

            o TX BP HF/6m ver1

            o TX BP HF/6m ver2

            o TX BP HF/6m ver3

            o RX BP/LP HF/6m           

            o AVALA TX BP/LP HF/6m

      o LP/BP for 100-500kHz

      o HF Multiplexer Filters

o HF SDR receivers

            o DR1

            o DR1A

            o DR2

            o DR2A

            o DR2-2

            o DR2B

            o DR2C

            o DR2D

             o DR2E

            o DR2G

           o DR2A+,DR2A++

            o DR2F+,DR2F++

            o DR2H+,DR2H++

         o DR2I+,DR2I++

            o DR3X

o HF SDR transmitters

            o DT1

            o DT2

            o DT2A

            o DT2A1

o HF SDR transceivers

            o ADTRX1

            o AVALA-01

o VHF/UHF receivers

            o AR1

            o AR1B

            o AR1C

o RF/SDR accessories

            o HF/VHF oscillators

            o CMOS SDR oscillator

o Complementary designs

            o Synthesizer RZ6HY

            o Miniwhip PA0RDT

            o OK2CPV SMT receiver

o Events, SDR workshops



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DC (direct conversion) transmitters

   I made several different DC (direct conversion) transmitters in past mainly professional type. High performances DC transmitter is not simple  construction and final specification depend from many things. In part about DC receivers I gave some solutions for blocks which are the same with DC (direct conversion) transmitter. Testing my SDR transceiver designs enforced me and I come back in past and tried some old solutions. Missing SDR free software for transmission at my SDR transceiver design at the beginning of 2006 I try to solved with some classic I/Q AF design with help a new free software. The results are very curious for HAMs who want to make direct phasing type SSB transmitter. Here I present a lot different realizations and simulations for normal AF bandwidth or SDR  frequencies up to the 20 kHz. Some solution from this design I included as part of the realized control board B2A2.


          SDR RX DR2H++ ,DT1A ,YU1LM AF shift network and IQPRO AD9854 DDS LO DC transceiver built by

          Jean-Michel TR8JH


            AF audio shift network built by Jean-Michel TR8JH