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...
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American and Standard Wire Gauges. Matching Table.
Wire gauge is a measurement of wire diameter. In world there are two general systems for measuring gauge. This is (SWG) – Standard Wire Gauge and (AWG) – American Wire Gauge. In table below...
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...
Antenna on the 40m band with low height of suspension
This is the simple “Delta Loop” Antenna on the 40m band with low height of suspension. Its upper corner located at the height of λ/4. I.e. for this antenna acceptable any mast with height...
Grundig – Few Words about History of the Great Company
Grundig began with the opening of a store called Fuerth, Grundig and Wurzer in 1930 in Nuremberg, Germany. In 1945 Max Grundig built and sold two testing devices, the “Novatest” and “Tubatest” – the...
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...
LoTW application appeared for Android and iOS.
The application called “MyLoTW” and works with ARRL LoTW service on Android and iOS platforms. The mobile application allows you to: Look through all the QSOs loaded into LoTW. Add new callsigns to your...
Simple modification of the HM-36 Microphone from ICOM
The Icom HM-36 microphone is a simple electret mic. But many owners notice that some microphones sounds bad. What reason? There are two different types of ICOM microphone HM-36 (exclude chinese fake): First type...
Dipole antenna design. Some theory and construction.
A dipole antenna is a symmetrical antenna, consisting of two quarter wave elements, connected to each of the two conductors (inner and outer) of a coaxial cable. You will need a center insulator for...
Antenna Loop Feed Array Yagi on 50 MHz band
The Yagi antennas with a frame vibrator, located in the plane of the antenna, are called LFA-Yagi (Loop Feed Array Yagi) and are characterized by a greater operating frequency range than the usual Yagi....
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