Search results

A website and email reflector for hobbyists in the unlicensed 49MHz low-power band.

Home made keyer with 8 memories, auto spacing, adjustable speed & weighting, separate paddle and key inputs, beacon mode, positive or negative keying, fuse, extremely low power requirements, and a bullet proof housing by AA5TB

Convert a PC power supply for your ham radio transceiver

Connecting centre fed antennas, dipoles, yagis, rhombics, loops to coaxial cable, unless care is taken, it is not difficult to end up with feeder radiation resulting in power loss and the radiation characteristics changes

Power supplies, rf power amplifiers, dummy loads, frequency counters, repeaters antennas manufacturer based in Italy

Schematic of a regulated 0-24v 2A Power Supply

Whether we are tuning up homebrew equipment, checking antenna VSWR, adjusting a linear amplifier, or just monitoring output power during a contest, almost all aspects of ham operation can use a power meter. Paul Wade W1GHZ

Increase TS 480 PEP power level

A simple accurate power splitter for the 70cm uplink to Oscar 13

This article presents a technical investigation into spurious emissions from the Yaesu FT-847 transceiver when operating on the 70MHz (4-meter) band. The author discovered significant problems with both factory "UK spec" and modified units. Spectrum analysis revealed that when transmitting at 70.2MHz, the radio produces numerous spurious signals, with the most prominent emission at 45.6MHz measuring only 3dB below the fundamental frequency. The study also documents poor power efficiency on 4m (10.3% at 30W output) compared to 6m operation (23.5% at 30W). Tests verified that jumper configurations had no effect on filter selection. The author warns that using these radios on 4m may violate license conditions due to excessive spurious emissions.

Converting a ZETAGI B303 power amplifier for 50 MHz usage

HAMIC, is a program designed to simplify a number of calculations commonly used by HAMs. It is designed for the HAM radio hobbyist, but may be useful to others as well. HAMIC has a simple to use, but powerful graphical interface that allows solving simple circuits such as resistors in series or parallel, or more complex circuits such as L networks or T networks. As well, other calculations such as SWR and reactance conversions are supported. Windows shareware.

Converting A PC Power supply for Amateur Equipment

Building a PEP Power circuit for all analogue watt-meter

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

Technical and modification information on Astron Power Supplies compiled from a number of different sources by Mike Morris WA6ILQ

Circuit diagrams drake tr7, Schaltbilder Drake Tr7, antenna tuners, baluns, and home brew power supplies, dual tone ssb test generator, zweiton ssb test generator, zweiton testgenerator, dual tone test generator by DK4DDS

This article documents the modification of 2 types of Hewlett Packard switching power supplies to enable their use as power sources for ham radio equipment

SPE Makers of RF power amplifiers like Expert 1K-FA Expert 2K-FA

G3WZT design for a bi-polar 600W Linear Power Amplifier for the 6M band.

This homebrew six-meter linear amplifier started off life as a "junker" Alpha 76PA h.f. amplfier. Power output is 800W

Collection of modifications for the Heathkit SB-200 RF power amplifier

Engineering Solutions for Unique Problems. Manufacturer of high Voltage, high Current, high Power Power Supply

An RF power Amplifier for HF bands with 3 GI-7B tubes by CT1FMS

The circuit is based on two AD8307 log amplifiers, which are connected to the forward and reflected ports on a directional coupler

A simple RF power amplifier initially designed for 40 meter band can work on 10 15 20 40 80 meters

A lower power desktop linear with integrated 120vac power supply. This, very compact, dual 811 version will deliver about 300 watts output. Covers all bands including WARC bands.

Baluns / Ununs design and acceptable power

DIY kits a 70W SSB linear Power Amplifier for YAESU FT-817 KX3 running HF 80m-10m bands

Small, but growing, group of amateur radio enthusiasts, most of whom are within 90 miles of Atlanta, are interested in promoting the development of the branch of amateur radio known as QRP - building and operating low power transmitters, receivers and transceivers.

Every ham needs an RF power meter. Here is a high performance unit to build at home.

High Power RF Amplifiers by Delta Sigma, Inc

An engineering oriented organization specializing in the design and manufacture of high performance parabolic antennas, 3dB high power RF couplers, Antenna power splitters, directional RF couplers and more items for RF transmission from HF through Microwave frequencies.

The two linear amplifiers are ment for use with QRP SSB/CW/FM/AM transmitters on the amateur bands 15 and 17 meters can be powered from a 12 volt DC supply by ON6MU

A perfect companion for your Elecraft K1 or any other (not power hungry...) QRP rig

HF power amplifier project powered by GU-78B by SV8JE

This article provides a basis to brew your own emergency power pack depending on your needs and tastes.

ON6MU 4 A power supply using a BDX33

The document provides a comprehensive overview of baluns, which are devices used to connect balanced loads, like dipole antennas, to unbalanced inputs, such as coaxial cables. It covers various types of baluns, including voltage and current baluns, and their design, construction, and testing. The text discusses the importance of baluns in preventing RF currents on coax shields and their applications in Ham radio setups. It also includes practical advice on selecting and using baluns based on antenna impedance and power ratings, along with detailed performance evaluations and construction tips for different balun configurations.

Modifications for the Kenwood TS-940, TS-940S LCD Clock Display Erratic Operation, Talk Power Improvement, erratic display, ALC mod

Class C tuned VHF power amplifier for the 6-meter band by ON6MU

Construction details of a multiband dipole that can can operate at high power levels, and match its 50-ohm coax feedline without a tuner

Offer a wide range of homebrewing projects mainly for VHF UHF operations. From vhf antennas to preamplifiers, chargers and power supplies

SM5BSZ article on building VHF RF amplifiers

A Low -Power Indoor Portable HF Antenna by Monty Northrup, by N5ESE

Receiver converter that can be plugged to the backside of the Yaesu FT-817 battery powered portable transceiver

How atenna tuners works and what are real effects on feed lines and maximun power output by G3TXQ

Interesting post with a practical video of using solar panel with a yaesu ft-857.

VoiceKeyDeluxe (VKD) will convert your sound card into a powerful and versatile digital voice keyer for contest or EME operations by N7QJP

An home made RF Amplifier project that allows near full power output from 813 tubes