HAM Radio site Blog

Variable Power Supply Unit. 0

Variable Power Supply Unit. DIY.

This little circuit is a copy of a design which was built around twenty years ago. The heart of the unit is based around a 723 regulator chip. It has variable voltage and current...

6m to10m converter 0

6m to 10m converter

This circuit is based around mixer/oscillator IC2. A 50mHz signal is fed to pin1 input of IC2 and mixed with the local oscillator injected at pin7. The resultant output is the antenna frequency minus...

National NC-100 Receiver 0

National NC-100 Receiver

As received, this National NC-100 was in a very sorry state. Several knobs were missing, as were most of the valves (and those that were there were not the correct ones). The set had...