spectrum circuit

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.

Getting the most from your tuner - Here is how to adjust this popular tuner circuit so it transfers maximum power to your antenna without going snap

A remote antenna tuner - Interesting project to remotely control, using a servo control circuit, a common commercial antenna tuner by N30X

Fun With Tubes - A noncommercial site operated by Max Robinson and dedicated to passing on and preserving knowledge of vacuum tube circuits and techniques.

Antique Radio Schematics and Capacitors for Tube Radios - Specializes in antique radio schematics and capacitors. carries antique radio schematic diagrams and electronic circuit service information for american, canadian and european antique radios.

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.

220 MHZ Spectrum Management Assn - Amateur radio spectrum management and frequency coordination entity for 219

T.A.S.M.A. - Amateur radio spectrum management and frequency coordination entity for 2-meters in southern california.

AOR U.S.A., INC. - Aor u.s.a web site, manufacturer of base and mobile receivers, handheld receivers, digital voice modems, spectrum display units, frequency monitors and antennas

Spectran - Cheap hand held Spectrum Analyzer

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).

ARDF transmitter for 80 meters - The 80m TX described here is the well known ON7YD ATX-80 and timer, combined and re-engineered to fit a readily available enclosure by G3ZOI

glfer - 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

Linrad - 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.

PSK08 for Spectrum Lab - PSK08 for Spectrum Lab.Small user file to configure the software for slow PSK.

RX-PSK31 - 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

AM-6154 FAA Amplifier circuit conversion - AM-6154 222MHz grid Conversion Information by N0UK

Rotator Brake Delay and Protection Circuit - A rotator modification by W4ZT

A simple VOX circuit - Here is a 3 transistors 6 diodes circuit that is a Voice Operated Tx PTT control as well as an ANTI VOX circuit to stop mis-operation from Rx noise by G8MNY

Soundcard Audio Tools and Toys - Soundcard audio tools and toys, experimental ideas and utilities. Signal Generator, Frequency-counter / instrument-tuner, Real-time Spectrum Analyser

Homebrew FT 817 Headset - A simple circuit to homebrew your own headset for the Yaesu FT-817

A Power Supply on the Cheap - Need a variable power supply that is short circuit protected and over voltage protected; Here is a good one that can be built cheap by VE3IVJ

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

A regenerative receiver with 6SN7GT - Circuit to build a regenerative receiver