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A Variable Base-Loading-Coil for use under a HF Mobile Whip

A multi-band portable vertical antenna can be built with relatively ordinary components obtained from the local hardware store, including replaceable loading coils

Experiments with spiral dipole antennas. Includes two spiral antenna designs for 20 and 40 meters band by KN9B

Using a full-size antenna and a reasonably sensitive headphone, this simple switching mixer will produce an amazing abundance of signals on 80m.

Intended for portable long-term usage and also good for Field Day Events article by By Steve KB1DIG & Kim KB1GTR

Live DX spots are presented through a _web cluster_ interface, utilizing both a world map and a Google Maps display for visualizing amateur radio propagation. The system provides real-time spotting data, enabling operators to track active stations globally. Users can observe current band conditions and station activity, which is crucial for optimizing contact strategies across various amateur bands. The platform's utility extends to contest operations and general DXing, offering a visual representation of where stations are being heard. While the primary function is DX spotting, the site also includes technical articles, such as instructions for interlocking two Flex Radios for single-transmitter compliance in contests, and a guide for constructing a simple **5KW** 1:1 balun for **160m/80m** dipoles using RG400 cable. This combination of live data and practical technical content supports both operational awareness and station improvement.

The skeleton slot antenna design was developed in the UK for TV use soon after WW2. This document describe and adapted version for the 2 meter band

This article is designed to be an introduction to the terms and basic mechanics of propagation methods that are to be found on the HF and VHF bands.

The SCOTIA Bandhopper a mobile multi-band vertical antenna

Yaesu FT-2000 Panadapter, using the Softrock 9 Lite, SDR receiver kit

The Icom PCR1000 review by GW0KIG

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

A two meter Quad antenna project with detailed instructions on how to adjust the Quad gamma match

This is an experimental CW transceiver for 80m, although the same idea will work on all HF bands

An Experimental, High-efficiency, Graphic-Tunable Magnetic Loop antenna and loop controller in a 52 pages PDF presentation with drawings and pictures

CWQSO allows you to practice sending and receiving morse code in a real QSO. You can send CW via the mouse buttons or an attached paddle, the CW you send is displayed on CWQSO

A Moxon rectangle antenna for 2 meters

The GM3VLB Poor Man's Antenna Analyser

Lights on why 160 meters is so unpredictable and what is being done to reveal its secrets

This is an Android application used to remotely control several HAM radio Web SDR or any CAT enabled transceiver

A project of a small antenna, just 50 cm for the 7 MHz band. An EH Antenna plan for the 40 meters band

Calculating HF helical whip antenna for mobile or portable operation

Guide to ground mounting antennas, notes on efficiency, elevated installations, metal towers and masts, other mounting schemas, moble homes and rv, lightning protections, artiche by Bencher

Article on how use Genesys sowftware to design RF power amplifiers

The design and feeding of driven elements for VHF/UHF Yagi antennas , modeling, observations and some case studies by Graham Daubney F/G8MBI

A large printable PDF file representing the world time zones. This map gives an overview of current local times around the world. If you ever asked yourself what time zone am i in, find your answer here.

A homemade tunable bandpass filter for all HF bands from 160m to 10m

An amateur radio contest log sheet printable in A4 format, useful for portable operations, free to download PDF File.

Useful exercise sheet to learn morse code reception. In A4 format PDF File, it contains groups of 5 characters commonly used while learning morse code reception.

This article compares two commercial vertical antennas for the 4-meter amateur radio band: the Watson WVB-70 half-wave and the Sirio CX4-71. The Watson measures 2.03m in length, costs around £40, and exhibited adequate performance but required additional waterproofing after rain affected its VSWR readings. The longer Sirio CX4-71 (3.02m) performed noticeably better, delivering signals approximately 2 S-points stronger than the Watson. The Sirio demonstrated high build quality, a stable 1.2-1.4:1 VSWR, and weather resilience, though minor VSWR fluctuations were observed during rain and frost. Both antennas are half-wave designs requiring no ground plane radials.

The information in this article has come from many amateur sources, the most notable was from WA6TEY (sk 1985) Ray Frost, who was a pioneer of VHF Quad designs and one of the best Southern California Transmitter Hunters. Ray built hundreds two meter quads in single and paired configurations as well as his famous mobile radio direction finding quad.

A page by 9A7PJT dedicated to HB9CV yagi antennas includes link to the HB9CV calculator program and some interesting plans

An Unorthodox Antenna, originally by W3AWH is considered a multi-band antenna suitable for fixed location use and as an easily deployable portable antenna for events such as Field Days.

A monster magnetic loop antenna for 160 meters band. This Magnetic loop is optimized for 1840 Khz + 50 Khz. PDF Article published on La Radiospecola 10.22

Paul Harden NA5N has produced a superb guide to solar activity and HF propagation for the QRPer

This document details the design and construction of the PA70H, a 50-watt RF amplifier for the 70MHz (4-meter) amateur radio band. Built around the Mitsubishi RD70HVF1 MOSFET transistor, the amplifier delivers 45-55W output with 3-5W input power while operating on 13.8V DC at approximately 7-8A. The PCB design incorporates multiple protection circuits including overcurrent, SWR, and temperature control. The amplifier features various control modes including GND PTT, +13.8V PTT, and RF VOX. Two versions are available: PA70HLI (requiring 100mW input with additional driver) and PA70H (for 3-5W input). The comprehensive documentation includes circuit diagrams, assembly instructions, and performance data showing successful operation from both 100mW and 3.5W input sources.

A moxon antenna project made with wires and fiberglass poles

Building the double size G5RV antenna, part list, assembly part, dimensions and assembly instruction in a pdf document

5-element antenna, with which G0JJL has worked lots of EU crossband, and won the RSGB Christmas Cumulatives 70MHz section twice in a row.

HAM-IV antenna rotor repari and restore

This PDF document details the construction of a **70 MHz** Big Wheel antenna, a horizontally polarized omnidirectional array. The design utilizes three full-wave loops, each approximately **2160 mm** in diameter, arranged in a triangular configuration. The resource provides mechanical dimensions for the antenna elements and a comprehensive bill of materials, specifying component quantities and types, such as M8 stainless steel bolts, 15x15x1.5 mm square aluminum tubing for spacers, and 8 mm aluminum rod for the arcs. The central hub is constructed from two 160x160x8 mm aluminum plates, with four 40 mm long polyamide insulators supporting the radiating elements. The feed system incorporates a 50 mm diameter aluminum pipe for mounting and a matching stub constructed from a 120x20x2 mm aluminum sheet, connected via M8x10 mm bolts. The resource includes a diagram illustrating the mechanical dimensions and assembly points, including the N-connector fixing point and the center conductor attachment. The project was published on May 25, 2011, by Peter OE5MPL and Rudi OE5VRL. DXZone Focus: PDF | 70 MHz Big Wheel | Mechanical Dimensions | **2160 mm** loop diameter

Using the Raspberry Pi to operate Weak Signal Propagation Reporter

Mountain Thunder CB Radio Group is a group of CB SSB operators that started in the Pacific Northwest, Washington State.

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

Most people are not familiar with antenna tuners and what a antenna tuner actually does.

With this tool it is possible to create QSO maps overlay on Google maps there each QSO get a line from the home location to each DX location. An EDI logbook file is used as input. The creation will only use complete locator in the 6 characters format.

Homemade Loaded Coil Dipole ( w8010 diamond ) for 10, 15, 20, 40 and 80 meter

A google map of the UK amateur radio repeaters with clickable information

A PDF File of a Maria Maluca multiband HF antenna with schematic diagram, dimension and plan

Ever need a way to estimate the amount of wire to add to or remove from a center-fed wire dipole antenna to achieve resonance at a desired frequency? This article help to determine correct wire lenght.