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An on-line museum featuring over 400 pictures of radios and related items from the 1920's

Three Yagi antennas for the six meters band by 9A7PJT. Include a 4 element yagi, a custom design 4 element, and a 5 element yagi with antennas pictures and design.

A description of a simple Lowfer beacon transmitter.

A synthesized 2.3 GHz Amateur Television (ATV) transmitter design, conceived by Ian G6TVJ, is presented, targeting broadcast-quality video performance on the 13cm band and extending up to 2.6 GHz. The core of the design utilizes a commercial Z-comm Voltage Controlled Oscillator (VCO) that tunes from 2.2-2.7 GHz, providing a +10 dBm output and simplifying RF alignment. This VCO's stability, originally intended for narrowband applications, readily accepts high-frequency video modulation, contributing to the transmitter's robust performance. The exciter stage, incorporating a Mini Circuits VNA 25 MMIC amplifier, boosts the signal to +16dBm, while a Plessey SP4982 prescaler divides the output frequency for the synthesizer. The synthesizer employs a Motorola MC145151 CMOS parallel IC, favored over the common Plessey SP5060 for its superior video modulation characteristics and ease of programming without microprocessors. This choice addresses issues like LF tilt and distorted field syncs often seen with SP5060 designs, particularly when operating through repeaters or over long distances. The MC145151 divides the signal further, enabling precise frequency stepping, with programming handled by EPROMs for channel selection and LED display. The loop filter network, critical for video integrity, was developed through experimentation to prevent the PLL from reacting to video modulation, ensuring a clean transmitted picture. The transmitter incorporates a Down East Microwave commercial power amplifier module, delivering approximately 1.6W output, driven by the exciter through a 3dB attenuator. Construction involves surface-mount SHF components on micro-strip lines etched onto double-sided fiberglass board, housed within a tinplate box. The design boasts no AC coupling in the video path, preserving low-frequency response, a common failing in other ATV transmitters. Performance tests with a 50Hz square wave revealed no LF distortion, and a calibrated "Pulse & Bar" signal showed a near 100% HF response, demonstrating its capability for high-quality ATV transmissions.

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

Dx-pedition in Lebanon on July 2004 by I1HJT - I1NVU - IK1QBT - OD5LN pictures and Log on-line it's available on web site. Qsl via I1HJT

Integrated PSK station for 80 & 20 meters without using a PC Pictures and diagrams by N2APB

Ten-Tec Orion II picture and specifications at RigPix

Radio Free Europe/Radio Liberty website provides news and information on various topics beyond borders. It includes top stories, visuals, newsletters, and in-depth coverage. The content is useful for staying updated on global events and perspectives.

A nice review of the Acom 1000 HF and 6 meter RFpower amplifier by Acom in Dutch and with online google translation available. Includes pictures and notes of the popular amplifier by Acom.

UV-3R Review at G4ILO Blog with long textual review, pictures and some sound files

A homemade 23 cm transverter project with several building steps and pictures

Homepage of radio club oz1als, contest results, pictures etc

remoteAudio is an multi platform Audio streaming application for Amateur Radio purposes. The most typical use case for this software is the remote operation of an amateur radio station. remoteAudio supports multiple users and multiple audio sources. At any time multiple clients can listen simultaneously on the same radio, although remoteAudio only allows one user to transmit.

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

The OZ1CX center-loaded mobile antenna project details the construction of a compact **80-meter** antenna, specifically designed for mobile, portable, and stationary operations. It features a loading coil wound on a 50 mm PVC pipe with 1.5 mm copper wire, comprising 100 turns over 150 mm length, resulting in an inductance of 150 µH. The design incorporates a 1.5-meter whip and a 1.5-meter base section, with the coil positioned at the center for optimal performance on the 3.5 MHz band. Performance measurements indicate a **VSWR** of 1:1.2 at 3.7 MHz when mounted on a vehicle, achieving a bandwidth of 30 kHz for VSWR below 1:2. The antenna's efficiency is compared to a full-size dipole, showing a signal strength reduction of 3-4 S-units, which is typical for compact mobile HF antennas. Practical application notes cover tuning adjustments by varying the whip length and coil tap points, emphasizing the importance of a good ground plane for effective operation.

Pictures of home made antenna launchers

QRSS pictures and examples from IW0HK ex IW1CXZ

Pictures, design plan and description of a 5 element yagi antenna for the 4 meters band by 9A7PJT

Valley of the Moon Amateur Radio Club website provides information on club events, history, officers, licensing, and how to join. Users can download newsletters, hamfest flyers, and net scripts. The club serves the Sonoma Valley wine country, holding monthly meetings, weekly nets, and breakfast gatherings. The club call sign, W6AJF, honors Frank Jones, an Amateur Radio pioneer. Various events are listed on the site, including picnics, VE testing, and breakfast nets.

K8CU technical topics article about high voltage breakdown tester necessary for testing of any high voltage components like vacuum tubes, high voltage capacitors, vacuum relay

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

A Picaxe Morse Code keyer project with source code and links to useful resources by K6ACJ

Understanding and using antenna radiation patterns

X7 antenna pictures during installation and report on first contacts.

This resource compiles claimed scores, often referred to as "rumor scores," for numerous amateur radio contests, providing a historical snapshot of competitive activity from 1993 through 2007. It lists entries for prominent events such as _CQWW CW_, _ARRL Sweepstakes_, _IOTA Contest_, and various _NAQP_ events, categorized by year and contest. Each entry typically includes the contest name and the month/year of operation, allowing users to quickly navigate to specific contest periods. The site also references the _3830 Web Page_ on Contesting.com as the primary submission portal for these claimed scores. The collection offers a unique perspective on contest participation and performance trends over more than a decade, preceding the widespread adoption of real-time score reporting systems. While not official results, these rumor scores provided early indications of top performers and overall activity levels for a wide array of HF and some VHF contests, including _ARRL 10M_ and _CQWW VHF_. The historical data can be useful for analyzing past contest popularity, identifying consistently strong operators, or simply reminiscing about earlier competitive eras in amateur radio.

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

EasyEDA - Web-Based EDA, schematic capture, spice circuit simulation and PCB layout Online.

Ten-Tec Orion picture and specifications at RigPix

Amateur Radio Youtube Channel with some picture slideshow compilations by VK5SW

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

Pictures of Hellschreiber machines as projected by Rudolf Hell

Twenty-four repeaters, including D-STAR and Fusion systems, are maintained and operated by MARCA Inc., primarily located on Arizona mountaintops and around the Phoenix metropolitan area. The organization, holding the callsign _W7MOT_, facilitates a wide range of amateur radio activities, such as ARRL Field Day events near Forest Lakes, Arizona, and participation in ARRL FMT contests. Members engage in antenna experimentation, construction, and maintenance trips to repeater sites. The club's interests span diverse topics, including HF voice, digital modes like _WSPR_, _WSJT-X_ (FT8, FT4), and CW, alongside DXing, MESH networking, and EOC operations. It supports technologies from SDR radio building to antique radio restoration and computer-based operations like Echolink, fostering a Single Board Computer (SBC) and Raspberry Pi group. Monthly meetings, held on the third Tuesday, feature business discussions and guest presentations, with informal summer gatherings and an annual holiday dinner in December. Monthly VE testing sessions for Technician, General, and Extra Class licenses are conducted by Ray Vasquez, K4RMV. Post-meeting discussions often cover specialized interests such as repeater operations, technical topics, D-STAR, SDR, APRS, Fusion, and Raspberry Pi projects.

Pignology is mainly an app developer focused on ham radio related topics. Offers radio remote control devices, and develop apps for them along to logbook apps and other ham radio related utilities.

The _Fuji-OSCAR 20_ (FO-20) amateur radio satellite, launched over six years prior, continues to operate reliably, despite a gradual decrease in its Nickel-Cadmium storage battery capacity and solar cell degradation. The satellite's power system can still supply approximately **10 W**, enabling operations. During the non-eclipse period, typically from mid-June through March, the satellite experiences a 0% eclipse rate, ensuring sufficient power generation. This allows for the potential operation of the onboard BBS, which had been previously suspended due to concerns about power shortages. An "eclipse rate" refers to the proportion of time a satellite spends in the Earth's shadow during each orbit. When the satellite's orbital plane is perpendicular to the sun's direction, the eclipse ratio becomes zero, meaning continuous solar illumination. Understanding these eclipse periods is crucial for managing satellite power budgets and scheduling operations, particularly for power-intensive functions like the BBS, which can now be considered for activation during periods of sustained solar exposure.

The Las Vegas Radio Amateur Club operates the K7UGE repeaters on 146.94 and and 448.500. Repeater is located on top of the Las Vegas Hilton Hotel & Casino, the UHF repeater is located on top of the Tropicana Hotel & Casino.

Amateur radio HSMM High Speed Multimedia, data and voice at ARRL website

PSK63 APRS mobile tracker for HF, FreeTrak63 - APRS PSK63 Tracker

23cm 1296 MHz Field Day Yagi Construction, a 26 element conventional-style design. Article with several pictures and detailed homebrewing instructions

Some observations on the Yaesu FT-817 5W portable HF VHF UHF transceiver with some pictures and movies

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

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

Schematic of a fast charger for Gel Cell batteries

Providing real-time weather spotter reports for the following counties: Delaware, Fairfield, Fayette, Franklin, Hocking, Licking, Madison, Pickaway, Ross and Union.

General information page including contest scores, station pictures

The "Shortish Guide to Using an Oscilloscope" elucidates the fundamental operation of oscilloscopes, detailing the purpose and function of vertical, horizontal, and triggering controls. It explains how vertical gain in Volts/cm and horizontal scale in sec/cm enable measurement of signal amplitude and timing, respectively. The resource differentiates between analog and digital scopes, noting that digital scopes often feature "soft" controls and are inherently storage scopes capable of capturing non-repetitive events. The guide dedicates a significant section to the critical role of oscilloscope probes, emphasizing their design to transmit waveforms without distortion or added noise. It explains the concept of a 10x passive scope probe, which reduces circuit loading by a factor of ten and eliminates waveform distortion through probe compensation, typically adjusted using a 1kHz square wave reference output. The document also provides practical advice on probe care and compensation procedures. Further sections address grounding considerations, explaining how a scope measures voltage relative to its chassis ground, which is tied to the protective earth. It offers troubleshooting steps for a blank screen and outlines essential good practices, such as checking input gain and probe attenuation, while explicitly warning against misusing probes or connecting the ground clip to mains voltage.

Full article on how to build a home-made wire dipole antenna for 40 and 80 meters band. Article is fully in italian, as it was published on ARI RadioRivista, but is plenty of self explaining pictures that will guide you on homebrewing this trapped dipole antenna for the lower amateur radio bands.

Fifty-three digital modes, including PSK31, RTTY, and JT65, are explored in this resource, providing detailed descriptions of their underlying technologies and typical use cases. It covers error correction methods like ARQ in PACTOR and FEC in JT65, alongside modulation schemes such as FSK and PSK. The content highlights the evolution of digital communication from traditional TNC-based systems to modern sound card implementations, emphasizing the role of personal computers in advancing these modes. Specific modes like AMTOR, PACTOR, and G-TOR are discussed, noting their baud rates and error correction capabilities. For instance, AMTOR operates at 100 baud, while PACTOR offers 200 baud with Huffman compression. The article also delves into newer modes like MFSK16, which uses 16 tones and continuous Forward Error Correction, and Olivia, capable of decoding signals 10-14 dB below the noise floor. Each mode's bandwidth, speed, and resilience to propagation challenges are examined, such as MT63's 1 KHz bandwidth and 100 WPM rate, or Hellschreiber's 75 Hz bandwidth and 35 WPM text rate. The resource also lists predominant USA HF digital frequencies for bands like 160, 80, and 40 meters, specifying segments for PSK31, RTTY, SSTV, and Packet. It includes links to freeware and shareware sound card software such as Digipan, FLDigi, and MixW, enabling amateurs to experiment with these modes.

TM-241E Picture and specifications

This resource documents numerous QRP (low power) portable amateur radio operations conducted by W1PID, Jim Cluett, primarily from various outdoor locations in New Hampshire. The content includes detailed accounts, photographs, and operational specifics for over 350 individual "QRP Adventures," often involving hiking, biking, or kayaking to remote sites. Each entry typically highlights the location, date, bands and modes used (frequently CW on HF), and notable DX contacts made with minimal power, sometimes as low as 200mW WSPR. The site serves as a chronicle of practical QRP field operation, demonstrating successful DXing and contesting from challenging environments. It showcases diverse operating scenarios, from mountaintops like Cannon Mountain and Knox Mountain to lakeshores, riverbanks, and even marine mobile operations. The documented contacts span numerous DXCC entities across Europe, Asia, and the Americas, providing empirical evidence of QRP's efficacy in varied propagation conditions and terrains. Specific events like the Worked All Germany contest, 13 Colonies Event, and CWT sprints are also featured.