variable

The Benchmark Beverage - The purpose of this page is to examine the performance of a typical Beverage when all variables except length are held constant

Comparator-based RF switch - This is a concept paper, not a constuction article. There are too many variables to propose a one size fits all design. However, this paper should give you the basic idea how to do it

Soft copper Tube Loops - Air conditioning soft copper tubes are perfect for loop construction. If you want to try a loop you must have an air variable capacitor or a vacuum variable capacitor. Article by PY1AHD

An automatically tuned 7-30MHz mobile antenna - This is a base-loaded vertical antenna that mounts on the car's roof. The loading coil is designed as a variable inductor, with a three-legged chariot that travels up and down inside the coil, with grooved brass wheels running on the coil turns, and driven by a slotted rotor tube.

Cheap antenna to make from 160m - 6m  ^pop - The antenna is nothing more than a simple 2.4 metre square loop drawing pinned to the internal brick wall of the spare bedroom. Yep, thats right, the inside wall of the spare bedroom - ideal for flat dwellers, hotel rooms or whinging neighbours, The loop has a simple switched inductance at the top of the square loop and uses a simple coaxial stub to tune the antenna. An additional variable capacitor placed across the feedpoint can be used to fine tune the resonance of the antenna, by Andy G0FTD

Multi-Elmac - THE MULTI-ELMAC AF-67 Trans-Citer is a ten-tube variable frequency or crystal controlled seven band transmitter.

Oren Elliott Products - Variable capacitors - The largest domestic manufacturer ofair-dielectric variable capacitors located in edgerton, ohio.

Hittite Microwave Corporation - Amplifiers, filters, attenuators, mixers, PLL, switches and frequency dividers, signal generators, power detectors, transimpedance amplifiers, variable gain amplifiers and more

DDS-60 Kit - A 1-60 MHz coverage VFO with built-in amplifier and variable output level from 0 to 4V p-p.

Omnicor - Vacuum Capacitors - Omnicor supplies Meivac vacuum fixed and variable vacuum capacitors for RF transmitters.

Hagerty Radio Company - Offer a Direct Digital VFO Kits (variable-frequency oscillator) using the Analog Devices AD9951 by WA1FFL

MobileLog Amateur Radio Mobile Logging - The MobileLog program is a specialty logging program designed for mobile amateur radio operators. It has been designed to allow quick entry of important information regarding QSOs. The software is primarily concerned with the logging of U.S. county information, which may be used to help work toward awards such as the USA-CA award for working all counties in the U.S.A. The data from this program may be imported into your general logging software. This sofware exports data in the ADIF (Amateur Data Interchange Format) and CSV (comma-seprated variable)

Trimitator - Software for imitation digital radio-signals: ASK, FSK, BPSK, QPSK, variable speed, any frequency

EhoCW - CW Keyer software by F8EHO keyer and decoder functions, with interfaces with emitter/Receiver, memories, variables for call sign, mp3 and wav morse conversion, direct keyboard keying, joystick or serial interface for a morse key

WSCGen - Signal generator using the PC soundcard to output continuous tone, CW, SSTV, AO-40 telemetry, and PSK31 test signals with variable AWGN. The program will also output to a RIFF .wav file by AE4JY

WD6CNF Voice keyer - Audio voice keyer Microphone input, speaker output Live microphone enable Record/play audio from twelve memories Display text of recorded audio Transmitter keyed via serial (com) port Loop (with variable delay) audio output

1.5 to 30 Mhz RF Amplifier  ^pop - This high range amplifier is very small [SB200 size] Vacuum variable input and output caps as well input and output switching.

Audio spectrum analyzer  ^pop - Analyzes audio from 10 Hz to 20 kHz, input from microphone or wave file, Variable sample rates (8000 Hz, 11025 Hz, 22050 Hz, 44100 Hz) Variable transform sizes (1k, 2k, 4k, 8k) Upper and lower limits adjustable Continuous, averaged, peak hold

Inductors and Transformers - Solenoids, variable inductors, electromagnetic induction, transformers theory at G3YNH

Variable bandwidth cw filter - As the sunspots return and DX propagation conditions to improve, the age old problem with QRM begins to show up on the amateur bands. Thif filter help you on improving reception

Homebrew a CW Filter - An home-brewed morse code CW filter with a central frequency of 800hz and a variable bandwidth from 230hz to 26hz by F5RDH in french.

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

Variable regulated power supply - 1.2-30V 1.5A variable regulated power supply

Multi-functional Power Supplies - Two types of multi-functional Home-brew 6/8Amps - 20 Ampere variable power supplies by ON6MU

Rig to Soundcard Interface by M0UKD - Practival project that contains two isolation transformers, one for AF from the tranciever to the line in on a soundcard, and one from the audio out of the soundcard back to the mic / data input of the radio. Both of which are variable inside the interface via two preset resistors.