Monthly Archive: August 2018

Optimus Pro CS 5 1

Communications Speakers

Have you searched and searched for a good speaker for your ham radio? That perfect speaker that would let you hear voices through the noise and static without hiss? A speaker that isn’t fatiguing...

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...