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Intermittent fluctuations of SWR readings with MFJ 259B antenna analyzer. -
This design has the following advantages low-cost components, Easy to set-up - nothing to adjust, no metalwork required, and only four soldered joints! -
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 -
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 coax cable impedance calculator -
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. -
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Azimuthal map with DX spot reporting updated online taking source from DX Cluster spot or Skimmer -
Some techniques on homebrewing yagi antennas by VK5AJL -
A summary or tutorial about the basics of the spectrum analyzer, what it is and what it is used for. -
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This page is a short description of the four phased verticals system for 160m 80m and 40m -
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. -
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Build you own RF probe, measure the level of RF voltage present at a particular point. -
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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. -
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Cheap but effective multiband quad antenna covering the entire horizon on 10-12-15-17-20m bands. -
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Amateur projects to investigate radiowave propagation - G3PLX's chirp project, ionosonde database, and more -
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 -
Connecting a Yaesu MD-100 dynamic desktop mic to the Kenwood TS-850 -
An overview of the basics of the horn antenna used in RF microwave applications. -
Refractive Index maps forecast for Europe -
Operated by the amateur radio club RK3AWL, Zelenograd Russia -
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 -
A Yagi-Mag antenna for the 4 meters band with NEC and MMANA files plans and pictures -
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. -
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QSL gallery mostly for the deleted countries, old prefix, Antarctic stations and also for the very old cards prior 1945 -
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. -
Forum post on differences between the Acom 1010 (single 4CX800) and Acom 1011 (Two 4CX250B) -
Jose B Rivera, N2LRB, shares his initial experiences with the Icom IC-7300, recounting a shift from skepticism to appreciation for the transceiver. He details how the radio's impressive Sherwood Engineering test results, ranking it #12, significantly influenced his decision, especially considering its competitive price point against higher-end options like the Elecraft K3s. The review highlights the IC-7300's strong receive capabilities, a key factor in N2LRB's purchasing decision, and notes the advantages of its SDR architecture for future updates. He describes the straightforward setup process, from unboxing and connecting PowerPole connectors to making a first contact with N0HQ, a special event station. N2LRB expresses satisfaction with the radio's clear audio and ease of tuning, even if the pan-adapter's utility for his operating style remains to be fully explored. He concludes that the IC-7300 offers exceptional value, providing SDR features and receive performance comparable to more expensive rigs at half the cost. -
Mods.dk modifications for the Kenwood TS-690 -
A facebook group where all women and girls in ham radio can gather together to share the common interest of amateur radio. -
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. -
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A forum thread about tuning with the Kenwood TL-922 TL-922A Power amplifier -
Programming memories manually the Baofeng UV-5R -
Baofeng UV-5R uses RS232 to communicate or programming with the PC software and you can make your own programming cable with a few components. -
Demonstrates the fundamental principles for connecting a personal computer to a ham radio transceiver, specifically for utilizing sound card-based digital mode software like those in the MM Hamsoft suite. It details the basic hardware setup, emphasizing the use of shielded leads and proper audio routing from the radio's output to the sound card's input, and from the sound card's output to the radio's microphone or data input. The resource highlights the critical need for transmit attenuation, suggesting a 100:1 voltage divider to prevent overdriving the transmitter's audio stage, and mentions the optional addition of ferrite beads and decoupling capacitors for RFI mitigation. The guide also points to external resources for more detailed pin-outs and interface schematics, such as a specific QSL.net page, and recommends consulting the help files within MM Hamsoft programs for interfacing specifics. It underscores that while the process is straightforward, understanding the audio level management and proper cabling is key to successful operation. The author, VE5KC, provides practical advice drawn from common issues encountered by operators setting up digital mode stations. -
Test equipment and ham radio related manuals -
A cavity filter, often a critical component in _duplexer_ designs, functions as a sharply tuned resonant circuit, allowing only specific frequencies to pass while attenuating others. These filters are essential for maintaining signal integrity in environments where multiple transmitters and receivers operate simultaneously on closely spaced frequencies, such as in repeater stations. The article details how these filters, sometimes referred to as _notch filters_, achieve high Q factors, which are crucial for their performance. Understanding the principles of cavity filters is fundamental for any amateur radio operator involved in repeater operation or designing custom RF front-ends. The discussion covers the basic circuitry and operational characteristics that enable these devices to provide significant isolation, often achieving **-80 dB** or more between transmit and receive paths. This level of isolation is vital for preventing receiver desensitization and intermodulation distortion. Properly tuned cavity filters ensure that a repeater can transmit and receive simultaneously on different frequencies without self-interference, a common challenge in VHF/UHF operations. -
How much better is an N over SO-239 at VHF/UHF, a discussion topic at eham -
Free windows program that download data from LoTW and modify an ADIF file exported from Logger32. This utility downloads data from LoTW and save data in the correct format required by Logger32. This program can be used instead of original ARRL scraper.exe tool. -
Distributed Antenna Systems technology used for gaining better coverage and using a lower power. -
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Gridmaker takes your ADIF-file and searches for all the grids on the specified band. It then makes files for use in DXAtlas