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If you want to build a repeater, this is the right place to start. Includes construction projects and reviews of repeater hardware available in the market.

An inexpensive condenser microphone with excellent performance can be easily constructed with easily available parts.

PSK31 Software for the EZKIT and Windows 95/98 PC

K9AY 160M / 80M Receiving Loop Antenna System by K7SFN

CTCSS Decoder and Encoder, DTMF Decoder projects

50 MHZ Moxon antenna based on the KG4JJH design with some slight modifications in the construction

This resource, "Transistor Audio Preamplifier Circuits," offers comprehensive design guidelines for constructing **bipolar transistor** audio preamplifiers. It delves into critical aspects such as quiescent current setting, voltage gain calculation, and the impact of various component choices on circuit performance. The content provides several _schematic diagrams_ illustrating different preamplifier configurations, including single-stage common emitter and two-stage designs, alongside explanations of their operational characteristics and practical implementation considerations. The analysis extends to frequency response, noise performance, and distortion, providing insights into optimizing these parameters for specific audio applications. The resource presents calculated gain figures for various stages, demonstrating how to achieve desired amplification levels. It also discusses the importance of proper power supply decoupling and input/output impedance matching, crucial for integrating these preamplifiers into larger audio systems or ham radio transceivers. The practical application of these designs is evident in their suitability for microphone preamplifiers or general-purpose audio amplification.

Demonstrates the construction and measurement of a single-turn HF receiving loop antenna, built from common materials like electrical conduit and lamp cord. The resource details the physical dimensions, including a 4-meter circumference, and calculates the theoretical inductance at approximately _6.4 uH_. It outlines a method for determining resonant frequencies across the 4-17 MHz range using a _C Jig_ and a _VR-500 receiver_, coupling the loop with a ferrite ring. The article also discusses the impact of receiver coupling on the loop's Q factor, noting a degradation in sharpness due to the transformer's reflected impedance. Analyzes the observed resonant frequency patterns, highlighting an unexpected rise in the loop's effective inductance at higher frequencies, particularly above 13 MHz. While some increase is attributed to distributed capacitance, the rate of rise suggests further investigation. The experimental setup provides practical insights into the challenges of maintaining high Q in simple receiving loops and offers a comparative reference for other homebrew antenna projects, such as those by _VK2TPM_.

A simple TRAP-dipole project for 20 and 40m bands includes EZNec simulations

A ground plane antenna for 80 meters band

WV7U's YC156 and 3CPX800 amplifier projects. Everything you wanted to know about using the YC156 or 3CPX800 in a ham radio linear amplifier. See pictures, schematics, test data, links, and more!

An interesting home made project of an L Network Antenna Tuner Project with pictures and schematics by K7SFN

An Arduino APRS project based on the real time OS BeRTOS

FAR Circuits is exclusively a manufacturer of Printed Circuit Boards for electronic projects that are used by the Amateur Radio and electronic hobby enthusias

14MHz SSB 10mW transceiver by JF1OZL

Design guidelines for Op Amp audio preamplifier circuits by Mike Martell N1HFX

xdx is a dedicated Linux network client for amateur radio operators who want to exchange DX (long distance) radio information

N1HFX article on adjustable voltage regulator

Long Range Wi Fi Antenna by AB9IL

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

A Lindenblad Antenna for 145 MHz and 435 MHz with an integrated 50 MHz J-pole

An introduction to history of Morgain Antenna, since the early origins in Virginia, to the current home made projects and design available on the net. Article in Italian

A combination of Fldigi and Flmsg for portable devices running Android used for NBEMS

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

136kHz portable station project by PA4VHF Dick

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

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

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

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

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

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

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

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

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

A controller for the miniVNA using an Arduino UNO and touch screen color graphic LCD display

Make your own loading coils for antenna projects using Caterpillar Grommet strips.

Key your transmitter from the tone output of a Morse Code generator program

Comparison of 50 and 70 Mhz antennas, commercial and home made projects

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

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.

Collection of telegraph keys homebrew antenna projects links to radio software

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

A complete guide to Baluns and transformers by WK5AJL

Establishing a robust, interconnected communication infrastructure across challenging terrain, the Island Trunk System (ITS) provides a network of open amateur radio repeaters for general and emergency communications throughout Vancouver Island, surrounding waters, and parts of the lower mainland on the West Coast of British Columbia, Canada. This system, largely off-grid, relies on solar power and batteries, necessitating careful operation, especially during night hours and low solar charging seasons, to preserve its energy resources. Maintaining the ITS involves significant effort from many hams, who appreciate adherence to regulations, including proper station identification. The system hosts a weekly social net every Monday evening at 8 PM, welcoming all participants, and also supports a Vancouver Island Region Emergency Radio Net each Wednesday at 19:15. Experimental projects like the Newcastle Ridge webcams, linked via 5.8 GHz broadband backhaul over 206 km to Nanaimo and Comox, demonstrate the innovative spirit within the ITS community. A new VHF repeater, operating on 146.880 MHz with a 141.3 Hz PL tone, was installed in Tofino, expanding system coverage.

W3EDP antenna assembly instructions and dimensions with pictures in this PDF File

RFAC Solutions specializes in providing a range of RF components, including various connector types, cable assemblies, attenuators, and filters. Their product line features common connector standards such as SMA, BNC, TNC, N-Type, MCX, and MMCX, essential for reliable RF signal paths in amateur radio and commercial applications. The company also offers high-power VHF amplifiers, catering to needs for signal boosting in specific frequency ranges. Their offerings extend to dust caps and adapters, which are crucial for maintaining the integrity and versatility of RF systems. The focus on supplying components from South Korea suggests a commitment to specific manufacturing standards and supply chain practices. This resource details a vendor's product scope, useful for hams sourcing specific parts for shack builds or antenna projects. Jeff is listed as a contact for inquiries.

A four element 2 meter quad antenna project

Selecting appropriate cabling for amateur radio installations, whether for antenna feedlines, control lines, or station wiring, is critical for optimal performance and safety. This resource provides access to a manufacturer specializing in a broad range of electronic and electrical cables, including options suitable for various ham radio applications. Their product line encompasses standard and custom cable solutions, designed to meet specific operational requirements for both indoor shack setups and outdoor antenna systems. The company emphasizes _proven quality_ and compliance, with products certified by the Canadian Standards Association (CSA), Underwriters Laboratories (UL), and Intertek (ETL). Their quality management system is registered to _ISO 9001:2015_, ensuring consistent product standards. They offer competitive pricing and utilize AI-logistic tools for reliable on-time delivery, serving customers globally with technical support. Access to detailed technical specifications and an online quote tool is available for registered site members, facilitating precise cable selection for projects requiring specific impedance, shielding, or environmental ratings.

Roger, G3XBM, shares his extensive experience in **QRP** (low-power) amateur radio operation, detailing various aspects of transmitting with minimal power. The resource provides insights into VLF (Very Low Frequency) reception techniques and the construction of simple **crystal radio sets**, reflecting a foundational approach to radio experimentation. It includes links to external resources covering QRP clubs, online receivers, manufacturers, and technical references, offering a curated collection for enthusiasts. His page serves as a hub for those interested in the challenges and rewards of QRP, often comparing the efficacy of different low-power setups. The practical application extends to understanding basic radio principles through hands-on projects like crystal sets, which G3XBM has explored. The collected links provide a starting point for further research into specific QRP equipment or operating practices, drawing on G3XBM's long-standing engagement with the QRP community.