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1500 watts PEP output from a Kenwood TL-922 amplifier requires careful attention to parasitic suppression and component selection to ensure stability and longevity. This resource critically examines common modifications, often based on anecdotal evidence rather than sound engineering principles, that can degrade performance or introduce new issues. It highlights how replacing aged components often gets misattributed to the efficacy of unnecessary modifications, leading to widespread misinformation within the amateur radio community regarding amplifier stability. The article details specific, effective modifications for the TL-922, such as shortening anode-to-chassis and anode-to-grid paths to improve VHF stability and efficiency. It addresses issues like incorrect capacitor types in the tank circuit, inadequate grid grounding, and poor RF sheet metal design, providing practical solutions like adding direct ground connections for the plate tune variable capacitor. The author also discusses proper parasitic suppressor design, emphasizing the importance of lead length and component selection for optimal performance and harmonic suppression, contrasting these with less effective or detrimental 'magical suppression kits'.

The system consists of a pair of Morse practice oscillators connected by a piece of two-conductor cable. Pressing the key on one unit produces a sound in both units by Peter Parker VK3YE -

A selection of alphabets used, particularly by ham radio operators, to spell out words

DL7JV Christian report his direct experience on magnetic antennas

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

Isolation vs antenna separation an interesting article by WA6ILQ

A short multi-band vertical antenna

A 4-Band vertical antenna that needs NO tuner, NO traps. Implement an LC matched on 4 bands with relay switching.

Dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links. Parabolic Reflector Antenna: Dish Antenna The parabolic reflector antenna which is often called the dish antenna provides an antenna solution applicable for VHF and above where high gain and directivity are needed for all type of radio communications and radio reception.

To aid in learning and improving Morse code proficiency, this resource offers an extensive collection of downloadable MP3 audio files. The content includes character practice groups, common words, punctuation, and full-length novels, all rendered in CW. Speeds incrementally increase, catering to both beginners and those aiming to build speed, with options for _Farnsworth_ spacing at lower WPM and standard spacing for higher rates. The resource also provides a Perl script, `gus_morse.pl`, allowing users to generate custom audio files from UTF-8 text. Users can download archives of sequential MP3 files, with options for English, German, Spanish, Esperanto, and Italian content. The audiobooks progress from **5 WPM** to over **40 WPM**, with some archives offering _omnibus_ collections of multiple works. The site emphasizes the importance of consistent daily practice and patient aural observation to develop procedural memory, moving beyond conscious dit and dah counting to direct character recognition. It also details the transition from Farnsworth to normal spacing, aligning with FCC and ARRL recommendations.

The Double 5/8 is a natural extension of the Single 5/8 and uses a 5/8λ element for both the top and bottom radiators.

Phased wire vertical antennas for 40 meters band

The X80 multi-band HF vertical antenna, a commercial iteration of the Rybakov design, exhibits a physical length of 5.5 meters, or approximately 18 feet, and is constructed from aluminum tubing. It operates as a non-resonant vertical, requiring an external antenna tuner for impedance matching across its intended operating frequencies. The antenna's design incorporates a 1:4 UNUN at its base, facilitating a nominal 50-ohm feed point impedance for the coaxial cable. Performance observations indicate effective operation on 40 meters, 20 meters, 15 meters, and 10 meters, with reduced efficiency on 80 meters and 160 meters due to its relatively short electrical length for these lower bands. Comparative analysis with a G5RV dipole and a half-wave end-fed antenna reveals the X80 offers a lower take-off angle, beneficial for DX contacts, particularly on the higher HF bands. Field tests conducted with an Icom IC-706MKIIG transceiver and an LDG AT-100ProII autotuner demonstrate the X80's ability to achieve acceptable SWR across 80m through 10m. The antenna's compact footprint and ease of deployment make it suitable for restricted spaces or portable operations, though its performance on 80 meters is noted as a compromise compared to full-size resonant antennas.

Alan Applegate (K0BG) article on mobile oprtations

Quarter wave omni-directional spider antenna for 2.4GHz 802.11b

6 Meter 1/4 Wave Antenna by Mike Fedler N6TWW. A detailed article with pictures of construction details of this 50 Mhz antenna

A magnetic loops for HF pedestrian mobile project by VK3YE

Assembling a Code-Practice Oscillator, a PDF by ARRL

Windows Magnetic Loop antenna design software by DG0KW in Detusch

A dipole antenna for 7 MHz support for this antenna is fiberglass military mast

PalmProp is a software for PalmOs dedicated to the forcast of HF radiowave propagation by f5hla

Mounting on Roof or at Ground Level? Why ground plane antenna works better at lower level.

An article at NFARL web site about differences in setting up a half-square antenna versus a Loop Skywire by W4QO

A step by step approach for a ham radio vertical antenna mount using only a hole, gravel and a piece of plumbing pipe

Use this online calculator to determine the length of a quarter-wave antenna from the frequency. Both metric and English units of measurement are supported.

Guglielmo Marconi's foundational contributions to wireless communication began in 1894, inspired by Heinrich Hertz's discovery of radio waves in 1888. His initial experiments at his family home near Bologna quickly demonstrated signal transmission beyond line-of-sight, achieving distances up to **two miles** within a year. Marconi secured a patent in 1896, subsequently gaining interest from the British Admiralty after disinterest from the Italian government. By 1899, Marconi's system facilitated transmissions across the Bristol Channel (nine miles) and the English Channel (31 miles). A pivotal moment occurred in 1901 with the successful _transatlantic transmission_, defying the prevailing belief that Earth's curvature would limit practical range to approximately 200 miles. This achievement catalyzed the rapid development of the wireless industry. Marconi continued refining his inventions and, in 1909, shared the _Nobel Prize_ in physics with Karl Ferdinand Braun for their advancements in radio technology.

VHF UHF half wave flower pot antenna project by VK2ZOI

W4TI Review of the ICOM 735

A conversion of a 80m dipole into a 160m vertical antenna

Modifications and improveents for the realistic DX-100L HF receiver by ON6MU

A pdf file with drawings and instruction to properly assembly and solder most popular coax cable connectors

QST Article on what you should know about matching networks for class C RF power amplifiers

Schematic diagram of the VLA 200 power amplifier by RM Italy

This QST article describes the electrical and mechanical design process for two LPs that cover the HF bands from 10-30 MHz

Web Morse Runne is an online CW (Morse code) contest simulator developed by DJ1TF - Thomas Fritzsche. This tool allows users to practice their Morse code receiving and sending skills in a simulated contest environment. Key configurable parameters include CW speed, with options ranging from 300Hz to 900Hz, and RX bandwidth, adjustable from 100Hz to 600Hz. Users can also set a monitor level and simulate various band conditions. The interface includes counters for calls and QSOs per hour, along with a timer. Pre-defined function keys are available for common contest exchanges such as F1 (CQ), F3 (TU), F6 (B4), F7 (?), and F8 (NIL). The simulator is designed for ham radio operators looking to improve their CW contesting proficiency.

A eham article on a square copper dipole antenna for 50 MHz by K0FF

Ground Plane antennas and common mode

U.S. Office of Cuba Broadcasting

These photos illustrate the basic steps in making a perfect solder joint on a p.c.b

A system designed to automatically tune small transmitting magnetic loop antennas, particularly beneficial for **contest operations** where rapid frequency changes are common. The core of the system involves a PC-based control application, AutoCap, written in C#, which monitors antenna SWR via an external meter and commands a motor interface to adjust the loop's variable capacitor. The software is compatible with Windows and Linux via the Mono framework, offering a graphical user interface for monitoring system status, SWR, power, and motor commands. Key components include one or more magnetic loop antennas equipped with DC or stepper motors for capacitor adjustment, an SWR meter with data output (such as the Telepost LP-100A or a homebrew serial/USB SWR meter), the AutoCap PC software, and a motor interface. The most effective motor interface utilizes an **Arduino-based controller** with custom firmware, providing precise control over both simple DC motors and stepper motors, and supporting features like motor braking for finer adjustments. The system allows for configurable SWR thresholds, pulse widths, and motor effort settings to optimize tuning speed and resolution. Optional radio integration provides frequency hints, enabling the algorithm to learn the relationship between motor actions and resonant frequency, thereby speeding up initial tuning responses. The software also supports antenna profiles, allowing operators to save and recall specific configurations for different loops, including accumulated frequency hint data.

Pneumatic Antenna Deployment Systems

Millimeterwave/Microwave transmission lines and components, Cryogenic temperature application transmission cables and systems, Permittivity(Dielectric rate) and Permeabillity measurement systems, Antennas, Radar systems

A collection of technical articles on antennas, radios and other stuff.

A 2 element 40 meters band parasitic delta loop antenna project with pictures and details

Vertical phased antenna systems plans by G3WZT

Installing the optional TCXO, named SO-3 in the Kenwood TS-590S by TK5EP

Taking the venerable SMK-1 design to 20m and adding an RF amp, audio filter, and a TiCK Keyer ... by Wayne McFee, NB6M

Magnetic Loop Antennas for The Radio Operator with Limited Space, a two part series of articles on how to construct a magnetic loop antenna, including directions on selecting high voltage tuning capacitor

Antenna tuners are crucial for matching the impedance of antennas to the 50 ohm output impedance of transmitters. The _LDG Z-11 Pro_ is an automatic antenna tuner designed to handle up to 125 watts, making it suitable for a wide range of amateur radio applications. Its compact form factor allows it to pair well with transceivers like the _FT-857D_, providing a portable solution for operators who frequently change locations or setups. The tuner covers the 80 through 6 meter bands, offering a broad impedance match capability. Although it struggles with some loads, it performs well with typical ham antennas, even managing to load an 80 meter dipole on 6 meters. One of the standout features of the _Z-11 Pro_ is its 8000 memory slots, which enable it to remember successful matches and quickly retune when revisiting frequencies. This memory function significantly reduces tuning time, often to less than half a second. The unit is well-constructed, with improved pushbuttons and a sturdy metal case that offers good shielding. However, users should be aware of potential RFI issues and the lack of a power switch, which requires disconnecting the power cord to turn off the unit completely. Overall, the _LDG Z-11 Pro_ is a user-friendly and cost-effective tuner, offering advanced features that enhance its utility in various amateur radio setups.

An effective multiband HF Vertical antenna, used as remote station antenna. Pictures and review of this vertical HF antenna by VK5SW