Jeff Duntemann's Technology Projects 
1995: A small resistance-tuned NBFM receiver using the MC3362 cordless phone chip. The circuit was published in the July, 1988 Ham Radio Magazine and the PC board was offered by the author.
1995: A small resistance-tuned NBFM receiver using the MC3362 cordless phone chip. The circuit was published in the July, 1988 Ham Radio Magazine and the PC board was offered by the author.
Viewed: 6854 times.

1996: I designed and built a 3W FM transceiver for the 6M ham band. I called it the 96er. (A "Sixer for the 90s.") It took me eighteen months, and whereas it worked, it could never get the power output amp to be completely stable. I learned a lot, though.
1996: I designed and built a 3W FM transceiver for the 6M ham band. I called it the 96er. (A "Sixer for the 90s.") It took me eighteen months, and whereas it worked, it could never get the power output amp to be completely stable. I learned a lot, though.
Viewed: 6062 times.

1996: Inside the 96er. I packed 4 PCBs into that little bitty box.
1996: Inside the 96er. I packed 4 PCBs into that little bitty box.
Viewed: 6072 times.

4/97: This is The Head of R&D (RAD) a robot puppet creature I built with Meccano parts for a friend's stage show. The eyes rolled, the mouth moved up and down, and the eyebrows tilted up and down, which gave him an amazing range of facial expression. I worked him through linkages from under a card table, and watched stage happenings on a wirless TV link under the table!
4/97: This is The Head of R&D (RAD) a robot puppet creature I built with Meccano parts for a friend's stage show. The eyes rolled, the mouth moved up and down, and the eyebrows tilted up and down, which gave him an amazing range of facial expression. I worked him through linkages from under a card table, and watched stage happenings on a wirless TV link under the table!
Viewed: 6111 times.

4/97: RAD on his storage table, so you can see the control pillar beneath his head.
4/97: RAD on his storage table, so you can see the control pillar beneath his head.
Viewed: 5834 times.

9/97: This is a PC board lashup of a 6DQ5 CW transmitter for 40M. I never transferred the design into a box; in fact, I don't recall writing down the details of the circuit. Worked well, and put out more power than a 6L6 in a similar circuit. The power supply in a galvanized iron box is also home-brew, and put out 440VDC plus AC filament feeds.
9/97: This is a PC board lashup of a 6DQ5 CW transmitter for 40M. I never transferred the design into a box; in fact, I don't recall writing down the details of the circuit. Worked well, and put out more power than a 6L6 in a similar circuit. The power supply in a galvanized iron box is also home-brew, and put out 440VDC plus AC filament feeds.
Viewed: 5819 times.

9/97: Close-up of the 6DQ5 lashup. The black metal tube is a 6AG7 in a pierce oscillator.
9/97: Close-up of the 6DQ5 lashup. The black metal tube is a 6AG7 in a pierce oscillator.
Viewed: 6051 times.

1998: This is a very haywire lashup of a space-charge auto receiver, just as a first fling with space charge tubes to get a sense for what they can do. On the left is the RF section, in the center the IF strip, and on the right the audio section, including a power transistor speaker amp.
1998: This is a very haywire lashup of a space-charge auto receiver, just as a first fling with space charge tubes to get a sense for what they can do. On the left is the RF section, in the center the IF strip, and on the right the audio section, including a power transistor speaker amp.
Viewed: 5032 times.

1/2000: This is the Tinderbox, a 7-watt CW transmitter based on a single 6T9 Compactron tube.
1/2000: This is the Tinderbox, a 7-watt CW transmitter based on a single 6T9 Compactron tube.
Viewed: 7195 times.

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