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An article on RFD antennas, resonant feed-line antennas

How to measure the characteristic impedance of a unknown transmission line using MiniVNA

Choosing the right feed line for your antennas, is a critical decision to your station setup.

Understanding the operational impact of Broadband over Power Line (BPL) on amateur radio communications is crucial for any radio amateur, especially given the potential for significant radio frequency interference (RFI). This ARRL tutorial delves into the technical aspects of BPL, explaining how the technology operates by transmitting data over existing electrical power lines, which can inadvertently radiate broadband noise across various amateur bands. My own field experience, particularly on the lower HF bands, has often involved tracking down noise sources that exhibit characteristics consistent with BPL emissions, making this a pertinent topic for maintaining clear receive conditions. The resource further details the specific FCC rules and regulations implemented to restrict BPL deployment. These regulations aim to protect licensed radio services, including amateur radio, from harmful interference. It outlines the technical standards and operational limitations imposed on BPL systems to minimize their impact on the electromagnetic spectrum, a critical aspect for contesters and DXers alike. For those engaged in RFI mitigation, the tutorial provides a foundational understanding of the regulatory framework that can be leveraged when addressing BPL-related interference issues. It serves as a valuable reference for hams seeking to comprehend the technical challenges and regulatory solutions surrounding this pervasive noise source.

Design a parallel circular wire balanced transmission line with this online calculator. This calculator is a tool for designing balanced transmission lines with a specific desired characteristic impedance Zc and made of parallel circular conductors of a given diameter d.

A lot of good things, not for QRP fans.

RSGB World Prefix Map - Radio Amateur's Map of the World

A Resonant FeeD line (RFD) antenna for 7 MHz prohect tested and tuned.

HF Beam Calculator for Amateur Radio and CB Communications

Cocos-Keeling Islands, Christmas Island Online Log

Design Guidelines for JFET Audio Preamplifier Circuits By Mike Martell N1HFX

Blog pour Radioamateurs. A Blog for radioamateurs mainly in french

This site is dedicated to design and analysis of micro- and millimeter wave filters from 0.5 to above 100 GHz.

A funny online application that lets you build your own QSL cards based on templates. You can choose background text aligment and text to be printed on your card.

Site of the section NOL Noord oost limburg Belgium

ladder-line is great - extremely low loss, even at high SWR. However, many hams refuse to use it because they are afflicted by common misconceptions

The skyline amateur radio club official website with club news, links and hamfest information as well as forums

Search the online log for 9X0T 9X0Y DX Peditions 2018

A home made 50 MHz KW power amplifier project with picture and PCB schematic by W6PQL

5Z0H Kenya 2010 dx pedition on-line log

Common causes of failues, due to wrong clamps. About Guy Anchors

Linear amplifiers cold adjustments with network analyser (VNA)

Online log search for 5W0M Samoa 2013

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

ZK3N On-line Log search

Facilitates logging of amateur radio contacts directly within a web browser, enabling seamless operation across various devices including Windows, macOS, Linux, iOS, and Android. This web-based application stores all log data securely in the cloud, providing accessibility from any internet-connected location. It supports importing existing log data via CSV files, with future plans for _ADIF_ file import, and offers a robust QSL card generation feature, producing print-ready PDF files in standard 148mm x 100mm dimensions. The platform integrates with Japanese government databases to automatically populate callsign-related information such as station location and license issue dates, streamlining data entry. It also assists with JCC/JCG searches for accurate QTH logging. The service leverages SSL encryption for all communications and benefits from security oversight by certified information security professionals. Users can register using email/password or existing Facebook/Google accounts, and the beta version is currently available for free. The system has processed over **5,297,881** logs, with **28,369** logs recorded in the past 24 hours.

Aggregating real-time contest scores, this online scoreboard serves as a central hub for participants and spectators to monitor live progress during amateur radio competitions. It directly interfaces with widely used contest logging programs, collecting score data as operators make contacts. The platform then processes and displays these scores on dedicated contest pages, offering an immediate overview of standings. Supporting a diverse range of **DX contests**, the system accommodates various operating modes and rulesets. It facilitates score tracking for events like the YB DX RTTY, RSGB Commonwealth (BERU), EA PSK63, and the South America 10 Meter contest, among others. This functionality allows contesters to gauge their performance against competitors instantaneously, fostering dynamic participation. The scoreboard's integration with multiple contest log software applications ensures broad compatibility, making it accessible to a significant portion of the contesting community. It provides a crucial service by centralizing score visibility, enhancing the competitive experience for **amateur radio operators** worldwide.

Search the VP6D on-line log dxpedition to Ducie Island with DXA real time QSO dashboard.

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.

PY0FF Online Long by Andre in SA-003 Fernando De Noronha Archipelago

Antennas, Transmission Lines, Tuners - Myths, Mysteries and Qualifiers By Don Wilhelm W3FPR

Gold Line, a manufacturer, provides a range of professional audio test and analysis equipment, including specific products like the **ZM1 Impedance Meter**, which is relevant for amateur radio operators needing to characterize antenna systems. The site also lists various noise sources and microphones, such as the TEF04 Mic, indicating a focus on audio signal integrity and measurement. The resource details contact information for repairs, calibration, quotations for specific products like the ZM1 and ZM1P, and technical support, with distinct email addresses and phone numbers provided for each function. This structured contact approach facilitates direct engagement with the appropriate department for specific inquiries. Operational changes effective March 1, 2019, are noted, directing users to VLDESIGN for repair and calibration, and to Partha Chen for ZM1/ZM1P quotations. Louis Pittsley is designated for technical support, with a general inquiry phone number also available, outlining the company's support infrastructure.

Online coax cable impedance calculator

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

How to setup a proper antenna feed line with a particular attention to RFI by K0GKJ

The Southwest Metro Amateur Radio Transmitting Society, Inc. is a non-profit club dedicated to promoting the Amateur Radio hobby.

About greyline propagation in HF bands

Pictures of a homemade monoband linear amplifier for 160m band powered by 3 x QB5/1750

The collinear antenna, or Marconi-Franklin antenna, is an omnidirectional, high-gain antenna composed of in-phase half-wave dipoles aligned vertically. By using quarter-wave transmission line segments, it maximizes gain at a low horizon angle, outperforming a half-wave dipole. Adding segments increases gain but narrows bandwidth. A popular DIY version, the CoCo antenna, uses half-wave coaxial cable segments connected by non-radiating transmission lines. Built with stable velocity factor cables, a matching quarter-wave sleeve balun, and ferrite rings for attenuation, the antenna achieves performance comparable to commercial models.

A browser based circuit simulator offering a large set of functionalities allowing to share and discuss designs

DesignSpark PCB is the world's most accessible electronics design software, specially designed for Rapid Prototyping and turning your circuit ideas into testable boards faster. Easy to learn and easy to use, DesignSpark PCB is free and can you can download DesignSpark from this site.

ARDF-Funksportreferats im DARC

French amateur radio blog

Training books and study guides for the UK Licence

Transferring Radio Frequency Energy from Your Transmitter to Your Antenna by Don Keith N4KC

3D2C ONLINE LOG for conway reef 2012

A simple dipole for 40m band feeded with 450-Ohm openwire feedline includes MMANA Gal files to download

Online morse code conversion tool

On-line Log for K5P DXpedition to Palmyra atoll 2016