Building Coaxial Traps
- This page describes the design and construction materials W8WWV used to build a coaxial cable trap. A coaxial cable trap is a parallel resonant circuit that is usually inserted in an antenna element to enable multiband operation.
Multi Band Antenna Traps
- These devices are called Traps, but they are actually more like frequency sensitive switches. They are parallel resonant, high Q, tuned circuits which provide a very high impedance at their frequency of resonance.
Canadian Antique Radios Schematics Diagrams Service
- We specialize in canadian antique radio schematics for vintage tube radios made in canada. we carry lots of factory electronic circuit schematic diagrams as well as all rcc / radio college of canada service data 1920's - 70's.
E. H. Armstrong
- Radio's premier inventor, Edwin H. Armstrong was responsible for the Regenerative Circuit (1912), the Superheterodyne Circuit (1918), the Superregenerative Circuit (1922) and the complete FM System (1933).
- glfer is a program for reception and transmission of QRSS/DFCW signals. It is composed of two main parts: the spectrogram window, where you can see the spectrum of the received signal vs. time
the transmission functions, to emit cw characters at a slow but precisely controlled speed, using the QRSS (slow CW) or DFCW (Dual Frequency CW) modes
- Multiplatoform freeware DSP software. Linrad has its origin in software that was developed for 144 MHz EME CW but it is quite general and should be seen more like a kit for designing a receiver that a receiver for some particular usage.
It can be used as a CW receiver with a small time delay and a fast waterfall graph. A dsp for conventional receiver to imporve signals readability, a spectrum analyzer.
- Easy to use Audio Spectrum- and PSK31 decoding program specially designed for SWL's who don't need TX or for anyone who just like to monitor PSK31 or analyse signals. Adjustable DSP and Spectrum settings for audio and frequency spectrum analasys or to set it for best decoding of PSK31 signals. By ON6MU
External Keypad for FT-817
- An external keypad for FT-817(ND), for the serious portable/field-day contester/operator. Homebrew it with the free firmware and public circuit diagram.
The circuit is very simple and takes power supply from the ACC port of the radio