Search results

HX-B5i five band HexBeam installation

Schematic for Yaesu FT-857 CAT interface

The TIC ringrotor offers operators the ability to have true On-the-Tower control of single or multiple antenna arrays for a full 360 of rotation

A pictorial guide to the basic ways of desoldering joints

A multiband quarter wave vertical antenna that works on 5 bands.

by Adam M. Farson VA7OJ/AB4OJ

Phased vertical antenna system in french

The Assyrian Democratic Movement also known as ZOWAA . This political organisation is aiming to bring freedom and democracy to Iraq.

An easy method for erecting antenna masts using readily available material

A german documento on magnetic loop antennas

A moxon antenna for 11 meter band, suitable for 27 Mhz and 28 Mhz

Demonstrates the product line of _LZ Antenna Ltd._, a Bulgarian manufacturer specializing in amateur radio antennas and custom electronic devices. The company focuses on robust, high-quality HF multiband Yagi and vertical antennas, leveraging over 20 years of experience from founder Georgi Georgiev in radio amateur development. Featured models include the LZA 8-4, LZA-10-3, and the LZA-7-3A WRTC 2022, alongside various rotary dipoles like the LZA1 40/30m. Provides specifications for several Yagi antennas, such as the LZA-9-5, LZA-13-7, and LZA-6-3 (a 6-element, 3-band design). The company emphasizes applying "leading edge technology" to high-frequency communication equipment production, with products designed for durability and performance. The LZA-10-5 Yagi offers **12.5 dBi** gain on 10m, while the LZA-13-7 provides **13.2 dBi** on 20m, showcasing competitive gain figures for DXing and contesting.

A vertical dipole for the 40 meters band made by using some buddipole parts and adding capacities on both ends by HB9MTN

By Guy, de ON6MU, At VHF, both the 1/4-wavelength monopole and the 5/8-wavelength monopole antennas are widely used.

An impedance transformer (9:1) to feed a high impedance long wire (~450 ohm), down to a 50 ohm unbalanced coaxial input.

A vertical portable antenna system by W0SJS that will work on 40, 30, 20, 17 and 15 meters

There is considerable confusion as to what exactly a multiband vertical antenna is. The confusion concerns the method of feed, how much mismatch one can expect, how many radials are required, how the particular antenna is built for multiband use, plus some other points.

A figure-8 double loop antenna

Ballistic simulator "Orbit" allows the physical principles of the motion in the gravitational field of the Earth to be demonstrated and learned. You can calculate with this program the ballistic trajectories of the thrown bodies and orbits of spacecrafts and visualize the astroballistic situation on the flat map of the world and on the rotating globe in the real time

A project of a vertical and wires that generate a multiband antenna for 28 14 10 and 7 Mhz in french

A project of a semi vertical trap antenna that can be tuned for 7 bands

A very short dipole with a good radiation efficiently plus a respectable bandwidth by S. C. Chuck Smith, WA7RAI

BaseStation is a Windows application written originally for the SBS-1 family of Virtual Radar Receivers.

The Nato and Western Union Phonetic Alphabets useful for spelling words and names over the phone.

CTCSS Decoder and Encoder, DTMF Decoder projects

Over 15 years of experience in DXing and contesting informed the development of _DXHeat_, a responsive web DX Cluster and analytics platform. This service delivers real-time DX spots, accessible on both desktop and mobile devices, featuring intuitive filtering capabilities. Users can quickly narrow down spots by band, mode, or specific callsign, streamlining the search for rare DX or contest multipliers. The platform integrates data from various sources, including traditional telnet clusters, the Reverse Beacon Network (_RBN_), and _PSK Reporter_, offering a comprehensive view of propagation and activity. Beyond live spotting, DXHeat provides extensive cluster analytics for individual callsigns, allowing operators to research past activity and propagation trends. This deep dive into historical data can be particularly useful for planning future DXpeditions or optimizing contest strategies. The interface is designed for serious DXers, prioritizing quick access to relevant information and robust data analysis.

Will we ever be able to dispel the myths? Steve Katz, WB2WIK/6

The array consists of 7 vertical antennas arranged as 6 verticals in a hexagon shape plus 1 additional vertical in the center of the hexagon

An Attic version for limited space applications by NW9T

GW4ALG's _136 kHz Pages_ document the evolution of vertical antennas for the 2200m band, starting with a prototype mounted on a house wall. This initial design, despite achieving the first **395 km** GM-GW QSO, suffered from significant insulation breakdown, high RF losses due to proximity to the house, and difficult tuning adjustments. The author details the challenges of maintaining resonance and matching with a variometer in the loft, noting that adding three earth spikes offered no measurable improvement over a simple water tap connection. The subsequent experimental 12m vertical, relocated away from the house, significantly reduced dielectric losses and proved far more effective. This antenna enabled GW4ALG to set a world DX record on 136 kHz with a **1916 km** QSO to OH1TN, and an intra-UK record of **703 km** to GM3YXM/P. The resource further explores the use of helium-filled balloons to extend the vertical radiator, achieving heights up to 27m, typically 20m, for enhanced low-band performance. Practical advice on balloon types, inflation, and critical insulation between the wire and balloon is provided, emphasizing safety and avoiding arcing.

A Quagi antenna project with pictures and dimensions for a UHF Quagi antenna

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 shortened 20m vertical antenna design made with 4Nec2

How to Operate Ham Radio on a Linux Workstation

One of the most useful antennas in the repertoire is the Marconi or quarter wave grounded vertical antenna. Its invention made it possible to halve the length of antennas, simplifying communications, especially at HF and below.

A vertical dipole for 7MHz and 21MHz by OH3GGQ

March Paddle by K4QU

Frank Donavan, W3LPL , discusses beverages on the CQ-Contest reflector. This is a reprint of Frank's message.

A 500-watt mobile antenna project details the conversion of an old 10m hamstick into a highly efficient, multiband "bugstick" for HF operation. The core modification involves replacing the original coil with 25 turns of 6 turns-per-inch, 1.5-inch diameter coil stock, fabricated from #14 wire. This design, intended for a 3-magnet mount on a vehicle cab, achieves resonance on multiple bands by shorting out specific turns on the coil, similar to a **bugcatcher** antenna. Measurements taken with an MFJ-259 analyzer on a GMC pickup show 0 turns shorted for 20 meters (14.2 MHz), 10 turns for 17 meters, 16 turns for 15 meters, 19 turns for 12 meters, and 23 turns for 10 meters. The construction emphasizes using UV-resistant tie-wraps and #14 solid wire with crimp lugs for robust RF connections, bypassing the fiberglass rod for current flow. A bonus section details a 40-meter version, utilizing 48 turns of 8 TPI, 2-inch diameter coil stock.

A light and portable magnetic loop antenna with improved bandwidth and performance by HB9MTN

How to build the Quickie Pneumatic Antenna Launcher

W0RW article that guide you to using beacons to determine dead bands or upcoming propagation openings.

Processing a single RTTY signal from a transceiver's 3-kHz audio, GRITTY employs _Bayesian statistics_ for superior decoding accuracy compared to traditional trial-and-error methods. This approach not only decodes 5-bit Baudot codes but also calculates the probability of error for each bit, enabling features like color-highlighting unreliable characters and smart squelching based on error probability rather than signal amplitude. This allows decoding of very weak signals while suppressing strong, undecodable interference, resulting in minimal garbage text. The program intelligently analyzes decoded text, comparing similar callsigns bit by bit and merging probabilities using the Bayes formula. This often allows GRITTY to determine the correct callsign and place it on the call stack even when all received copies are corrupt. The same methodology is applied to correct errors in exchange numbers and CQ/DE keywords, and to fix incorrect shift states. GRITTY offers an open API interface, documented in its Help file, for integration with other programs, allowing them to receive decoded data and mouse click events.

RADIOING eEngineer RFI EMI information

Antique Radio Schematics and Service Manuals for Tube Radios

Ameritron Al-811H Tuning for Power/Dissipation/Linearity, and More Generally 811A Tube Amps in Grounded Grid

Choosing a vertical antenna. Buying guide to amateur radio HF vertical antennas by Bencher inc

A magnetic loop antenna for 7 Mhz by ZL1BJQ

How could we share the Beverage antennas on more than one station using this homemade remote antenna switch, a project by TK5EP

James Miller G3RUH article on amsat site