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The 80 metre fox-or/test transmitter is a small low power transmitter which is designed to be used as an alignment aid for running up 80 metre foxhunt or ARDF receivers. It is also usable as a micro transmitter for fox-or-ing events.

Home Brew a 4-1000A RF power amplifier project by W4NFR

High Speed Multimedia Radio Introduction by ARRL Working Group Chairman. Report of the High Speed Multimedia (HSMM) Working Group ARRL Board of Directors 2006 Annual Meeting January 22, 2004

W1MX, the MIT Radio Society, stands as America's oldest college amateur station, providing a vibrant hub for MIT students, faculty, and staff interested in RF engineering, telecommunications, and radio science. The club, formerly known as 1XM, fosters a growing membership and hosts regular business meetings on the first Tuesday of each month at 7:30 PM ET, alongside weekly social gatherings every Friday at 7:00 PM ET in room 50-358. No prior radio experience is necessary to participate, and interested students are encouraged to attend a social meeting for a station tour and to learn about typical club activities. The society emphasizes experiential learning opportunities, actively seeking support to build a new and improved station at MIT. The club maintains a consistent presence in 50-358 during semesters and IAP, often extending into the summer, with the exception of club trips. Members can also access a dedicated webpage displaying the last 30 days of door activity, updating every five minutes, while a public frame shows the current door status and recent activity.

A searchable database of online websdr receivers, lists OpenWebRX, KiWi SDR and WebSDR from all over the world, providing a web interface to search and filter links to websdr

Whippanny laboratories Li L Lulu 50 to 54 Mhz amateur radio trasnceiver

WEB site of UT5UGR Dimitry

A 40 meter QRP - Transceiver by DL5NEG

A description of a simple Lowfer beacon transmitter.

A Linux Smith charting program. You can enter either discrete components or transmission lines, see the results on screen and/or generate Postscript output. Component values can be changed numerically or using scrollbar

Original article was in December, 1986 QST

In this article you can find solutions to the problem of keeping your ham radio antennas hidden from the CCR Police

160-10 Meters 1500 Watt Amp - W4NFR

Home Brew 6 Meter Amplifier with a single 4CX250B by W4NFR

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.

Vasantha VU2VWN VFO controlled 40m Tansmitter schematics

A Collection of EME Reflector Antennas and YAGI Arrays.

A Short Guide to Harmonic Filters for QRP Transmitter Output. - George Dobbs G3RJV

The official Summits on the Air discussion group.

ARRL documentation on how get reciprocal lincece or authoriazion to operate ham radio abroad

Amateur radio direction finding, transmitter hunting. triangulating a radio signal direction and plotting its bearing on a map. hunters use doppler systems for tracking hidden transmitters

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

SWR and Transmitters Friends or Foes!, making sense of it!

Lancaster Radio Transmitting Society Lancaster County, Pennsylvania

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.

Have wondered why a Smith chart has such strange grid lines. Believe it or not, there is a logical progression from Speedometers to Smith charts that will make the Smith grid crystal clear.

International supplier of radio astronomy products

A NiCAD Battery Charger with Current and Voltage Limiting

Web Page of the Fort Smith Amateur Radio Club

The Malaysian Amateur Radio Transmitters' Society (MARTS) serves as the national representative body for amateur radio operators across Malaysia, having been established in 1952. This organization plays a crucial role in advocating for the interests of Malaysian hams, fostering community engagement, and supporting the growth of the amateur radio service within the country. MARTS actively participates in national and international amateur radio affairs, often collaborating with organizations like the _International Amateur Radio Union_ (IARU) to ensure the continued development and recognition of amateur radio. The society's activities encompass a range of services for its members, including the dissemination of information regarding licensing, operating procedures, and technical advancements. MARTS also facilitates various on-air events and provides resources to help members improve their operating skills and expand their knowledge base. The organization's long-standing presence since 1952 underscores its commitment to the amateur radio community in Malaysia. MARTS supports local clubs and individual operators, promoting best practices in radio communication and emergency preparedness.

Official summits on the Air discussion group

A page dedicated to top band transmitting equipment and operations by VK3YE

A CW beacon keyer for 222 MHz by VA3NFA

Official site of ARI Comitato Regionale Friuli Venezia Giulia

Schematic diagram for a high voltage power supply by W4NFR

The details of the spark gap transmitter and its history: how it was invented, developed and used.

Founded in 1959

23 cm PA with Mitsubishi RA18H1213G

Summit Prowler 6 is a pocket-sized SSB/CW transceiver for 80, 40, 30 and 20m

This resource indicates that the specific page detailing the RockMite QRPp Rig CW transceiver project, previously hosted by WY3A on QSL.net, is currently inaccessible. The QSL.net platform, which provides free web hosting services to over 30,000 amateur radio operators and organizations, confirms the file or page no longer exists. Users are advised to attempt direct contact with the website owner or utilize an internet search to locate the content. The platform's error message clarifies that QSL.net support cannot assist in finding individual missing pages due to the decentralized maintenance of its numerous hosted sites. It encourages reporting any missing files related to the QSL.net main site itself. Donations are encouraged to support the free email and web services provided to the amateur radio community.

Personal page from Russian amateur radio station RW3FX

QRSS operations on 30M with an home made dipole

A homebrew radio transmitter project, based and inspired by the original 30 Watts input on 80 50 and 15 meters band transmitter by W11CP

What is VSWR and why you should care, formal definition of VSWR and SeaSonde Measurements, formulas

This page contains Contributions to a Discussion on the Moon-Net about the Application of Digital Signal Processing (DSP) Methods in Moonbounce.

A transmitter project for the 136 kHz band by IK2PII

This article describes the construction of a high performance transmitter and receiver for SSB (voice) communication covering the 14MHz (20 meters) high frequency amateur radio band with output range 15 to 20 watts and a top audio sound quality both on transmit and receive.

The interactive Smith chart enables users to navigate their way around a Smith chart, using simple discrete element impedance matching. This page allows users to try using the Smith chart, for education and interest purposes, without installing any software. Try changing the value in the load box to see the location of the impedance on the chart.

How to limit unwanted harmonics from your raspberry Pi radio transmitter by introducing filters.

Drake TR-7 A.M. Transmit Filter Modification