HAM Radio site Blog

Inverted L Antenna 0

Inverted L antenna for Reception

Do to it’s ease of construction, the most popular antenna for short wave reception is the inverted “L” antenna. It’s often just a random length of wire strung up as high as possible. My...

Velocity Factor of Coax 4

Velocity Factor of Coax

“The velocity factor (VF), also called wave propagation speed or velocity of propagation, of a transmission medium, is the speed at which a wavefront (of an acoustic signal, for example, or an electromagnetic signal,...

Hi Z Microphone Preamplifier Schematic Diagram 0

Hi-Z Microphone Preamplifier. Schematic Diagram.

This preamplifier for a high impedance microphone was built into a Harris limiter/compressor which needed a line-level input. Its response is essentially flat from 20Hz-30KHz. The 10uF capacitors are 25v Tantalums, the .01uF capacitors...

Drake R8 Receiver 1

Drake R8. Review of Shortwave Receivers

The Drake R8 series of shortwave receivers were introduced in 1991 until 2005 or thereabouts as R8, R8A, R8B and R8E. The latter being a version of the R8. Each of these different versions...

A Simple 40m Vertical Antenna 0

A Simple 40m Vertical Antenna

The 40m band is a great place for DXing! I don’t have the tall supports needed for a dipole or beam, so a vertical antenna works best for me. I do have a convienent...

Simple CW 10 m TX 0

Simple 10m CW Transmitter. Circuit Diagram.

The original circuit by the late Doug DeMaw W1FB, differs slightly from the one shown here. Two immediate differences are: A regulated DC supply for better frequency stability and a 2-pole low-pass filter for...