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A home made yagi antenna featuring 6db forward gain and 22 Db front back

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

A sourge arrestor for PL 259 connectors. A voltage surge arrestor to limit the voltage that may come back down the wire or coax after there has been static build up

A 21 MHz Four Square Beam Antenna This popular antenna for the lower bands, can also work well on 15 meters, QST Article

Service manual in PDF Format for the Yaesu FT-7800 transceiver

An end fed 20 meter half wave antenna

Alk engineering - filter design software and consulting

A 2-metre Quad antenna project by K6WXA in PDF file

A scanned PDF of this interesting book on HF Dipole antennas published by Stanford Research Institute

Shortwave Monitoring Station in Berlin: DX news, HF propagation, greyline, DRM news, QSL gallery, audio recordings and more

Schematic of Yaesu FT-857 main board original jumpers based on different radio type

An excellently presented article on the design and construction of a medium wave DX Antenna

In this article K3DAV show a very simple way to make an RF choke coil that will remove your RF feedback troubles

Packet Radio networking home page with lots of informations and tech. resources

A complete guide to magnetic loop antenna construction, with analysis of multi-turn and single-turn magneti loops, and and insight on choosing the optimal capacitor, or homebrewing your own butterfly capacitor

There are 2 possible TX extensions on the E version, either full TX (1.705 - 30 MHz) or just open up 5 MHz (cut the R968 jumper and make it into a K version). This mod has been tested on TS 590S and not on TS 590SG

Makers of universal digital rotor controllers including wireless controllers

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

club station VK2MB, Manly Warringah Radios Society, on northern beaches of Sydney, Australia.

Notes and details on repairing Traps on Cushcraft A3S

Coupling the Duracell DR36 battery to the FT 817 The main advantages on this system are, the weight, size, quick battery changing and no stress to the FT 817 power connector

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

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.

Microphone wiring for Yaesu FT-757 GX II

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

The webpage provides guidance on working 6 Meter DX, focusing on effective operating habits, preparation, and knowledge of the band. It emphasizes the importance of monitoring, clear frequencies, and using CW for weak signals. It also mentions the significance of knowing countries and individual stations on the air to increase chances of working DX. The page recommends utilizing resources like newsletters and websites to stay updated on 6-meter activity and offers suggestions for improving operating skills.

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

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

Otto engineering is comprised of two divisions otto controls and otto communications. otto controls designs and manufactures a full line of switches and grips used in heavy equipment, aerospace, marine, medical and other demanding applications. otto communications designs and manufactures audio accessories for two-way radios used in public safety, police, fire, retail, hospitality manufacturing and other markets.

A Moxon rectangle antenna for 2 meters

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

Calculating HF helical whip antenna for mobile or portable operation

Wiring Color Code and Pinouts for IC-706MkIIG and HM-103 Mic

Sherwood Engineering Inc. (SEI) offers a repository of technical presentations and white papers focused on optimizing amateur radio transceiver and receiver performance. Content includes detailed analyses of _roofing filters_, transmitted IMD, and receiver characteristics, with specific discussions on products like the Drake R-4C and Icom IC-781. Presentations from events such as Dayton Contest University (2008-2014) cover topics like "How To Optimize Rig Performance," "Transceiver Performance: 10 Years of Change," and "Choosing a Transceiver: Far from Simple." Additional white papers address HF mobile antenna efficiency, ground screen alternatives to buried radial systems, and common receiver problems with solutions. The site also provides historical product information for items like the SE-3 MK IV synchronous AM detector and various 455 kHz mechanical and crystal filters, though many products are no longer in production. Receiver test data and alignment tips for the R-4C are also available, offering insights into rig modifications and performance enhancements.

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

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

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

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

What electronic parts you can recover from PC monitor, VCR, CD-ROM, FDD, HDD , Laptop, Motherboard, SmartCard reader or Printer

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.

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.

Using the Raspberry Pi to operate Weak Signal Propagation Reporter

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

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

A method of installing a PL259 coax connector, a complete tutorial on how to solder Amphenol 83-1SP connectors

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

An overview of some of the ways, and the key tips on how electronics soldered joints can be unsoldered or desoldered.

70 MHz jpole half wave antenna by G7OGQ and G8CVF

If you need a cheap and easy to construct Subtone Generator for EU-model VHF-UHF rig, here is a solution that works very well.

80 to 6 meters, 2 KW, designed to be used at heights of only 25 to 45 feet, includes a twenty foot long vertical radiator