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This unit uses four capacitors, only two of which are variables, and a single tapped coil. It is built in a die-cast box, and has been tested up to 80W input power on 70MHz by G4CJZ

Wouxun KG-UV8D Standard Programming Software. Used to adjust or expand the frequency range to the full authorized range of the radio and not beyond. 134-174MHz 400-519MHz This software will Not add the 2.5kHz step.

Rotors and rotor controllers for amateur radio polish manufacturer.

The dbm online calculator and reference table for 50 Ohm

Horn Antennas theory and principles

This is a description of how KO4BB built his tower. It is provided in the hope that it will be useful to anyone want to setup his own ham radio tower.

Aka Circular Waveguide Antenna. This online antenna calculator let you plan your cantenna for the desired frequency of operation, giving the Can diameter you have available.

This tutorial will get you on the road to running your own live scanner feed on the Internet, be it railroad, fire/ems or law enforcement related.

Intermittent fluctuations of SWR readings with MFJ 259B antenna analyzer.

BKLog is a versatile log book and contest program designed specifically for amateur radio operators. Developed in VB.NET, it offers a user-friendly interface and a range of features that cater to both casual and competitive hams. Users can log their contacts, manage contest entries, and utilize automatic CW sending, making it a valuable tool for any operator. One of the standout features of BKLog is its integration with DX Cluster access, allowing users to stay updated on DX spots and enhance their operating experience. Additionally, it supports uploads to popular online QSL services such as QRZ, LoTW, and Club Log, streamlining the QSL process for users. With regular updates and improvements, BKLog continues to evolve, ensuring it meets the needs of the amateur radio community. Whether you're a seasoned contester or a newcomer to logging, BKLog provides the essential tools to enhance your ham radio experience. Its compatibility with Windows makes it accessible to a wide range of users, and its ongoing development ensures that it remains relevant in the ever-changing landscape of amateur radio.

Windows program to divide one big ADIF file to many shorter ADIF files, based on qso numers, in example to send it to LoTW.

The MMMonVHF database, curated by DL8EBW, currently lists 63,455 entries for VHF operators, providing a searchable resource for locating stations active on 144 MHz and higher bands. Operators can register their callsigns to be included, with specific criteria such as participation in _MS_ (Meteor Scatter), _WSJT_ modes, or _EME_ (Earth-Moon-Earth) operations required for inclusion in the `call3.txt` file. This resource facilitates VHF DX expeditions and contest planning by allowing users to identify potential contacts within a geographical area. The database supports various VHF/UHF operating modes, including those focused on weak signal propagation. Statistical data regarding the database entries is also presented, offering insights into the distribution of registered VHF activity.

This web article details the construction of a 4-meter band coaxial dipole antenna, designed for operation between **70.000 MHz and 70.500 MHz**. The resource provides a bill of materials and step-by-step assembly instructions for a half-wave dipole constructed from _RG-58_ coaxial cable. The design specifies a direct 50 ohm feedpoint impedance, eliminating the need for an external matching network. Construction photographs illustrate the stripping and soldering processes for the coaxial cable elements, ensuring proper electrical connection and physical integrity. The article includes specific dimensions for the radiating elements, derived from calculations for the 70 MHz band. The project outlines the physical dimensions required for resonance at 70 MHz, with the outer braid forming one half and the inner conductor forming the other. The feedline connection is directly to the coaxial dipole's center, maintaining a 50 ohm characteristic impedance. While the article does not present SWR plots or VNA sweeps, it focuses on the mechanical construction and dimensional accuracy for achieving a functional 4-meter dipole. The design is intended for fixed station use, with no specific mention of polarization or height above ground, but implies a standard horizontal orientation for dipole operation. DXZone Focus: Web Article | 4m Coaxial Dipole | Construction Guide | 50 ohm Feed

Club log, the popular online logbook service, offer an online general pourpose contacts log analysis including DXCC Charts, QSL Charts, log inspector, and many statistical reports with charts and log matching with other clublog users.

Modification and verification of the FT847 to optimize 70 MHz performance by G4FUF

This page is a short description of the four phased verticals system for 160m 80m and 40m

This design has the following advantages low-cost components, Easy to set-up - nothing to adjust, no metalwork required, and only four soldered joints!

1.5 dB of matched line loss can be calculated for a given transmission line using this online tool, which employs a model calibrated from empirical data. The calculator allows radio amateurs to input specific transmission line types, such as _RG-8_ or _RG-58_, and then determine the expected signal attenuation. This is crucial for optimizing antenna system efficiency and understanding power delivery to the radiating element, especially for HF and VHF operations where feedline losses can significantly impact performance. Beyond matched loss, the calculator also provides an estimate for mismatched loss if the Standing Wave Ratio (SWR) is specified. This feature helps operators quantify the additional power loss due to impedance discontinuities between the transceiver, feedline, and antenna, which is a common concern in amateur radio installations. Accurate loss calculations are vital for effective station design and for predicting actual radiated power. The tool's utility extends to various operating scenarios, from fixed station setups to portable deployments, aiding in the selection of appropriate feedline lengths and types to minimize signal degradation. Understanding these losses is a fundamental aspect of maximizing the effectiveness of any amateur radio antenna system.

Online coax cable impedance calculator

Azimuthal map with DX spot reporting updated online taking source from DX Cluster spot or Skimmer

A tutorial on using RF frequency counter, how a digital frequency counter works, includes frequency counter specifications and best practices in setting counter accuracy and resolution

Online VSWR Voltage Standing Wave Ratio Calculator

A summary or tutorial about the basics of the spectrum analyzer, what it is and what it is used for.

Some techniques on homebrewing yagi antennas by VK5AJL

Taiwan radio club

Beacons on 4 meter band

Homebrewing an W3HH Antenna in french

Connecting a Yaesu MD-100 dynamic desktop mic to the Kenwood TS-850

Build you own RF probe, measure the level of RF voltage present at a particular point.

An homemade antenna tuner project that should be small, easy to build and cheap. This automatic antenna tuner can work as locale or as remote. The tuner has EEPROM memory for store settings for faster tunning and four interfaces

A simple VHF quarter wave antenna from PL25

Cheap but effective multiband quad antenna covering the entire horizon on 10-12-15-17-20m bands.

Refractive Index maps forecast for Europe

A free website for the amateur radio community. Being a member gives you full access to the features and benefits of this forum.

An overview of the basics of the horn antenna used in RF microwave applications.

Spanish amateur radio forum with classifieds

A Yagi-Mag antenna for the 4 meters band with NEC and MMANA files plans and pictures

Summary, tutorial about the basics of what is a waveguide and the basic waveguide theory.

Antenna gain and directivity explained in this article at radio electronics antenna pages

Noise Canceller kit originally developed about 1989 by G4WMX and GW3DIX and improved by DK9NL and DG0KW.The VK5TM Noise Canceller is another version of the design, with the HF Vox circuit removed and a couple of other minor changes, including the use of SMD JFETs and a double-sided pcb.

Operated by the amateur radio club RK3AWL, Zelenograd Russia

Forum post on differences between the Acom 1010 (single 4CX800) and Acom 1011 (Two 4CX250B)

An economical way of building an SSB filter. The circuit is for a filter with a 6 DB band width of roughly 2.2 KHz.

Morse code quote of the day

Amateur radio antennas manufacturer based in Italy. Produces HF end-fed, dipoles, and other wire antenna types, mono band and multi band antennas.

This project is an APRS iGate for digipeater aboard the ISS. As the ISS pass over the iGate location, the TNC decoded the audio tones and creates data packets the Raspberry Pi can receive.

Mods.dk modifications for the Kenwood TS-690

Test equipment and ham radio related manuals

A forum thread about tuning with the Kenwood TL-922 TL-922A Power amplifier

How much better is an N over SO-239 at VHF/UHF, a discussion topic at eham