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Some rules of thumb for beginners, with a QRP approach, by James R. Duffey KK6MC/5

Build An Inexpensive Repeater Controller from a Basic Stamp 1 or 2 By Roger Cameron

The Collins TRC-75 autotune linear amplifier, owned by JF2SVU, is presented with a focus on its internal modifications. This QRO amplifier utilizes three 4CX250 tubes in parallel for its final stage, delivering 1 KW output power. Notably, the amplifier achieves full power with only 100 mW of RF input, a characteristic often associated with Collins designs. The original 400 Hz power supply has been converted for easier shack integration, and the entire RF and power supply sections have been rehoused into a compact, clean enclosure. The control unit, positioned above the amplifier, features three meters for individual vacuum tube IP monitoring and a multi-meter on the right. A dedicated 7 MHz receiver, recently completed, is also part of this integrated system. The autotune functionality means the main amplifier unit only requires connections for power, control, and coaxial cables, simplifying its operation. Key components like the 4CX250 tubes and NF capacitors are visible, along with the gearing mechanism for the final tank circuit. A timer and relay system manages high-voltage delay and cooling fan off-delay, although the cooling fan's airflow is noted as somewhat insufficient. A central volume control, which experienced a contact issue, is also highlighted.

This is a design for a stealthy HF multi-band vertical wire antenna using a tree as a supportby G7AQK

136kHz portable station project by PA4VHF Dick

Paddles made from readily available materials, like double sided PC board material and cost almost nothing to build.

This article document a 2 element half wave collinear J-Pole antenna by KC9EOT and KB8OJH

Tips and tricks on homebrewing your own Coax traps by ON7EQ

A New Twist on Portable Multiband HF Dipoles, a Multi-band Spiral Dipole Off-Center-Feed match (OCF) antenna solution.

This homemade tube oscilloscope is based on the WaterMan Pocket-Scope 0510A, a 3 tube oscilloscope made in 1946.

Amateur radio open source log program written in PHP. Put your log online for visitors to browse in real time. Access your log from any web browse, can run under windows linux and macos with apache, mysql and php

Digital Voice Transceiver Project This Project began to explore the use of the DVSI AMBE 2020 voice compression chip and also the ADF7021 single chip VHF RF Transceiver from Analog Devices.

The digital wattmeter project was created for the purpose of measuring power in the range of 300nw to 30w.

Displays the actual transmitting beacons of the NCDXF/IARU Beacon Project.

This article explain how to homebrew and use an HF antenna analyzer by simply adapting a Windows PC, micro-controller and a DDS evaluation board by K6BEZ

Rotator controller, azimuth & elevation control of rotators (automatic antenna turning) based on commands from computer. A project by Pavel VACHAL and OK1DX - KF9VM

Interesting article on multiband fan dipoles. This article give an overview on designing this wire antenna, and planning a robust installation and proper feed line. Includes notes on setting up a commercial fan dipole antenna and on how diy your own.

This antenna analyzer measures complex impedance over the 1.6 - 33 MHz HF spectrum

Lot of useful information on experiments on 136 Khz band, with antenna tips DSP infos and notes on their activity in LF.

A complete guide to Baluns and transformers by WK5AJL

DIY voice keyer for your next ham radio contest. An interesting homebew voice keyer project by ON7EQ

A project for a SDR receiver by Juan Domenech Fernandez

A four element 2 meter quad antenna project

Have you problem with your RG cables ? This page describes a smart antenna box using an RG-cathode for 3 antennas. The remote control needs just a simple wire and the GND for remote-control

The NCDXF/IARU International Beacon Project operates a worldwide network of 18 high-frequency radio beacons, continuously transmitting on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. These beacons, initially launched in 1979 with a single station and expanded to the current 18-beacon system in 1995, provide reliable signals for both amateur and commercial users to assess current **ionospheric propagation** conditions. The system's design, construction, and operation are managed by volunteers, covering hardware and shipping costs. The resource details the evolution of the beacon network, including the transition from Kenwood TS-50s transmitters to Icom IC-7200 radios with a new controller design implemented in 2015. It explains how listening for these 100-watt signals, transmitted to vertical antennas, allows operators to determine band openings and optimal propagation paths globally. The content also references three QST articles providing historical context and technical specifics of the beacon project. Practical information includes methods for identifying transmitting beacons via a schedule or specialized software like FAROS and Skimmer, which integrates with the **Reverse Beacon Network** for automated monitoring.

A remotely tuned 80m to 10m wire vertical antenna

Amateur Radio Projects & Kits for homebrewers, includes DDS,sound card interface,programmers, hamcom, frequency counter, RF Power Meter, modems and more.

Schematic anc PCB for a fox hunting receiver for 80 meters band

How to build a lightweight amplifier that can be backpacked around.

VK3YE magnetic loop antenna plan that cover 7 Mhz to 20 Mhz and shortening loop can work on 21 Mhz.

Tips to homebrew your own HF traps using aluminium wire and doorknob capacitor

The page provides a project for an helical dipole for the 40 meters band, resonating on 7 MHz, created by PY1ZFK based on a design by DL8VO. It includes detailed instructions on building the antenna.

This simple and cost effective interface circuit is designed for use with any ICOM amateur radio equipment with CIV interface

Home brewed spider beam by VA7ST

Diplexer is a passive device, a special filter circuit that seperates 2 different bands, not to be confused with the duplexer that usually separate 2 different frequencies on the same band.

A small random wire antenna tune that can tune from 40 to 10 meters bands.

A magnetic loop antenna working from 30 to 15 meters with 100W

This Z-Match is a link coupled all-band tuner. Two all band tank circuits cover 3-14mhz and 14-30mhz. The tank output links are selected with a very heavy duty SPDT rotary switch.

A DIY guide to build your own compact multiband HF antenna based on the G3TXQ version using a 1:4 balun. This article includes the full part list and instructions to assembly, including the center plate.

The future of two way radio is digital.

VE7AVV replace balun on a TH6 antenna

Article about small magnetic loop antennas with notes on realization of magnetic loops for several HF bands and the six meter band

Interesting article on how build your own field day antenna

Open-Source Software Implementation of a DRM (Digital Radio Mondiale) Receiver. Dream runs on virtually any pc and requires a receiver front-end to work as a real radio.

Design and build an 6 m dipole antenna from aluminum, tubing, that resembles the active element of a yagi beam antenna.

This article loaded with nice pictures and schematics, describes a 160-10 meter linear amplifier that uses a pair of 3-500Z triode power tubes. It was designed and constructed by William Moneysmith, W4NFR. The amplifier features fast warm up and 1500-Watt RF output with 100-Watts of drive.

The AE6AC 17-meter Moxon antenna project details the construction of a wire beam using readily available materials. This design utilizes four 16-foot fiberglass crappie poles for support, joined at the center with 3/4-inch Schedule 40 PVC pipe and "T" slip fittings. Wire segment lengths for 18.135 MHz were calculated using _Moxgen_ software by AC6LA, with specific dimensions provided in feet and inches for precise cutting. Key construction decisions include joining the crappie pole bases into a central hub and attaching the 16-gauge silver-plated copper wire to the pole ends. Dacron cord with a fisherman's knot secures the wire to the pole tips, while small wire loops at the corners maintain antenna shape. Plexiglas pieces serve as insulators for sections "A" and "C." The finished antenna, weighing less than 10 pounds, mounts on a fiberglass windsurfer mast and incorporates a 1:1 current mode ferrite bead balun. Performance measurements with an _MFJ-259B_ show an SWR better than 1.5:1 across the 17m band, with good front-to-back ratio and reported signal strength improvements of 2-4 S-units over vertical dipoles. Initial contacts included VK2AXB, ZF6GS, and KL1M.

Magnetic loop for 20 to 6 metres pedestrian mobile by VK3YE

The N3UJJ multi band cage dipole antenna project thay can fit a small property

This project hereby presented is a complete HAM radio simplex 'smart' repeater, built around a Motorola GM-350/950, Arduino NANO board and a WINBOND audio recording integrated circuit