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W6/PA0ZN CATV tuner based Spectrum Analyzer Building Project

Enabling IC 706 for 4 meter band modification in italian.

Sometimes amateurs like to home-brew their power supplies instead of purchasing one off the shelf at any of the major ham radio retail dealers.

The page is about the 144 Mhz Dirty Beacon project, a VHF beacon keyer by 9A4QV. It provides technical information, project details, and resources for amateur radio operators interested in beacon keyers. The content is useful for those looking to build or learn about VHF beacon keyers.

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

PA is a JAVA software package containing several programs, SW/VHF/UHF Logbook (imports format from RADIOMAN, VMT), Log conversion to HTML format, Import and export functions for RADIOMAN, CT RES files, BV QSL Labels, CSV etc. Internet DX-Cluster support, Keeps track of your worked Callsigns, Checks your worked Grid Squares per band, Databases for worked Grids and Callsigns Uses K1EA CQWW.CTY country file, Easy command line version for terminal operation Moontracking as clock, Pathloss calculation

PSK31 Software for the EZKIT and Windows 95/98 PC

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

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.

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

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

A ground plane antenna for 80 meters band

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

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

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

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

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

136kHz portable station project by PA4VHF Dick

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

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

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.

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.

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

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

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

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

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

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

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

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.

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

A project for a SDR receiver by Juan Domenech Fernandez

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

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

A four element 2 meter quad antenna project

A remotely tuned 80m to 10m wire vertical antenna