Hi to all homebrew BITX20 members,

??????? Hope everybody is having fun building their version of the BITX radio.

After attending?local hamfest at the end of February, collecting all the relevant parts, started assembly of BITX20.?The chassis, L? shape was salvaged from the power supply of a old ?Fax machine and it's circuit board was used a source of some of the parts for the BITX20. Lot's of good parts in old equipment hi hi. A piece of single sided pcb was fitted to the chassis, copper side up, and ye old ugly style construction began. The VFO was?built first and?a compartment of double sided PCB surrounds it. A red LED is used to fine tune the frequency and gives about 4khz range. Various coils were tried at L4 to improve frequency stability, ended up using a ferrite bobbin from the salvaged Fax board. The Receiver front end was built next, opposite side of VFO partition. T1 mixer transformer is mounted on the crystal filter side?(IF)?via a feedthru capacitor. The IF, BFO and audio stages assembled and tested next. ??Used 2N2222A transistors throughout except for the PA amplifier of course, the audio output device is a TDA2002.? The PA amp was built on a small heat sink salvaged from a old TV chassis, size?8 X 4.5 cm?. The 2N2218 driver coupled to IRF510 using TV balun taken from TV tuner, and some instability occurred when driving a reactive load. This was cured by fitting a ferrite bead directly onto the gate leg of IRF510 Fet. The receiver audio is very clear and sensitivity better than 0.5 uV.? Don't procrastinate, if your thinking it's all too much trouble, just have a go, you will learn more by doing.

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Many Thanks to Asher for allowing me too much fun..

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Best regards to all BITX members

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Alf VK2YAC