Dan Bedford's 1 Transistor Reflex Set
Here is a set that I have wanted to build since it appeared in Radio, Television and Hobbies in June of 1963. It used the (at the time) very latest "drift" transistor. As a school student on pocket money, the transistor was out of my reach.
Life and many other projects got in the way but here it is after a space of forty two years. The set is a one transistor reflex design with voltage doubling detection and regeneration. The transistor used is an OC169, but could be an OC170 or OC171. American builders could use a 2N370 or 2N371. The later AF117 would also be suitable.
I followed the circuit and general layout of Jim Rowe's original but the regeneration was touchy and would go from none to full oscillation harshly. I rewound the coil using 44/40 litz wire on a thin styrene former with no taps. It is now possible to sneak up on the "sweet spot" smoothly.
The set is a very hot performer and receives all my locals without aerial or earth. I'm happy to correspond with anyone wishing to build this set.
Here is the original article: (600-800k each JPG)
Transistor Reflex Radio Project, Page 1
Transistor Reflex Radio Project, Page 2
Transistor Reflex Radio Project, Page 3
Transistor Reflex Radio Project, Page 4