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Fellowship for all Amateur Radio Operators of Rockingham County. Home of the N4IV repeater system. Licensing classes, testing, ARES, and Skywarn

Some notes on double-shielded coaxial cable

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.

The South Mountain Repeater Association (SMRA) is a 501(c)(3) non-profit group of amateur radio operators dedicated to community service and emergency communications within Cumberland County and the surrounding area in Central Pennsylvania.

The Guernsey Amateur Radio Society (GARS) provides a central hub for amateur radio operators in the Bailiwick of Guernsey, offering resources like a local _GU Callbook_ and specific notes tailored for visiting operators. The society maintains an active presence, holding regular meetings on Friday evenings from 7:30 to 9:00 PM in a unique World War II bunker located within the grounds of the Beau Sejour Leisure Centre. Beyond in-person gatherings, GARS facilitates on-air activity with a 2-meter net operating on 145.525 MHz every Tuesday night at 8:00 PM. Additionally, a DMR net is hosted on Thursday nights at 8:00 PM via the _GB7GY_ repeater, catering to digital mode enthusiasts. These nets provide opportunities for local members and visitors to connect and exchange information. Phil Cooper, GU0SUP, serves as a key contact for the society, managing inquiries and web content. The club's location is precisely described as being down a concrete staircase to the left of the road when approaching the Concourse entrance, making it straightforward for newcomers to find their way to the club's distinctive meeting place.

The electchester vhf club is located in flushing, queens, ny and operates an arrl coordinated, 2 meter, vhf repeater designed for amateur (ham) radio use.

Provide an ATV repeater function for the North Jersey Exterior Area that is available not only for general amateur radio use, but also for providing a unique communications resource during emergencies as well (FCC Part 97.1 (a))

For over 50 years, Communications Specialists Inc. has been a cornerstone in specialized radio frequency solutions, initially gaining prominence with their **CTCSS** and **DTMF** tone signaling products widely used in amateur radio repeaters and commercial two-way radio systems. My own experience with their tone boards in various repeater builds confirms their reliability and ease of integration, a testament to their engineering. The company's legacy in tone encoding and decoding is well-established, providing robust solutions for access control and selective calling. Beyond tone signaling, Com-Spec has diversified into niche markets, including wildlife telemetry, pet tracking collars, and specialized tracking systems for model aircraft and rocketry. Their product line features compact transmitters and receivers designed for specific tracking applications, demonstrating a commitment to precision and durability in challenging environments. While some legacy products are no longer available, Com-Spec continues to innovate, as evidenced by the new R-30M receiver, which ships within five days. This focus on specialized RF applications, from tracking Alzheimer's patients to law enforcement, highlights their unique position in the radio communications industry.

The Broadcast Employees Amateur Radio Society, Inc. (BEARS) operates an extensive network of **VHF and UHF repeaters** across New York, the Hudson Valley, Long Island, and New Jersey, accessible to all licensed amateur radio operators. This resource details the club's structure as a 501c3 tax-exempt non-profit, emphasizing its role in providing ham radio training, testing, and critical communications support to various public and private emergency response agencies. Key repeaters include W2ABC/RPT on 147.27 MHz with a 141.3 PL tone, serving as a central point for club activities and broader network access. BEARS is also a founding member of the **Disney Amateur Radio Interconnect (DARI)**, a consortium of open, linked VHF and UHF repeaters spanning major metropolitan areas such as Philadelphia, Baltimore/Washington DC, Orlando, Bristol, Los Angeles, and Boston. This interconnected system facilitates wide-area communication for members and supports emergency preparedness efforts across multiple regions. The club's focus extends beyond Disney employees, welcoming aspiring and current hams from outside the company to participate in its activities and utilize its robust repeater infrastructure.

100-watt UHF repeater (444.500+ PL100) and a 6-meter repeater (53.68- PL114.8) are owned and maintained by South County ARES to support emergency communications for Belmont, East Palo Alto, Foster City, Menlo Park/Atherton, Redwood City, San Carlos, San Mateo, and Woodside/Portola Valley. The organization emphasizes training, including weekly nets and practice sessions, to improve message passing accuracy and brevity, crucial skills for **emergency communication**. Resources like the San Mateo County Sheriff's Office Ham Radio Frequency Plan Recommendation and **Chirp-compatible CSV files** for Baofeng radios are provided. Participation in community events is encouraged to build skills and connections among members. The group operates without collecting dues, relying on donations and member contributions of time and expertise. Training pages are available for new hams and those seeking license upgrades, along with a "Tips for New Hams" section. The site also features a monthly calendar of events, including board meetings, general meetings, and hospital nets, alongside a newsletter, the "South County Communicator," and various operational documents like the Net Control Manual and SCARES Handbook.

Presents the W9VT Tri-Town Radio Club, an ARRL-affiliated organization serving the Illinois amateur radio community. The club maintains a 2-meter repeater on 147.180 MHz (+600 kHz offset, 107.2 Hz CTCSS) and a 70-centimeter repeater on 444.825 MHz (+5 MHz offset, 107.2 Hz CTCSS), both located in Woodridge, IL. Regular meetings are held on the second Tuesday of each month at 7:00 PM at the Woodridge Public Library, focusing on technical discussions, operating practices, and community service. The club participates in Field Day, supports local public service events, and offers licensing classes for Technician, General, and Extra class examinations. Members engage in various amateur radio activities, including DXing, contesting, and digital modes, fostering skill development among hams. The club's repeater infrastructure provides reliable local communication for members and supports emergency preparedness efforts within DuPage County. Participation in ARRL-sponsored events like the Simulated Emergency Test (SET) and various operating awards promotes active engagement and technical proficiency. The club provides a platform for mentorship, allowing experienced operators to guide newer hams through licensing and operational aspects.

A General-Interest ARRL Affiliate Operating Open Repeaters in Canon City, Colorado

The JTRG is an active club affiliated with the American Radio Relay League (ARRL). and dedicated to further the art of amateur radio communication, serve the public, and promote high standards in amateur radio.

Dedicated to providing superior FM repeater service to Amateurs in the Washington, D.C. Metropolitan area.

Suburban amateur radio repeater is a wider coverage machine with six receiver sites in the chicago metropolitan area.

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.

Linked Repeater System in Darby, PA

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.

Enables every Ham to easily find repeaters across the the World, USA, Canada, Mexico and over 35 other countries, for free and without a network connection using the RepeaterBook Directory.

Radio Amateur WEB TV, Streams for and from ATV repeaters, Live streams for and from events, Amateur Webcams from holland

The Club Radio Amateur de Québec (CRAQ) is a prominent amateur radio club based in Québec, Canada, dedicated to fostering interest and participation in amateur radio. It provides a platform for local hams to connect, share knowledge, and engage in various radio-related activities, including **DXing**, contesting, and technical experimentation. The club supports its members through regular meetings, technical presentations, and organized operating events, aiming to enhance their skills and enjoyment of the hobby. CRAQ also plays a role in public service communications, often collaborating with local authorities for emergency preparedness and response. CRAQ's activities include operating club stations, organizing **field day** events, and offering training sessions for new licensees. Members frequently participate in provincial and national contests, contributing to the club's competitive standing. The club maintains a network of repeaters, providing reliable local communication infrastructure for its members and the broader amateur radio community in the Québec area. These resources facilitate daily QSO traffic and serve as critical links during community service operations.

With Doozy for Windows you can make QSO’s via your Windows PC on DSTAR ( DPLUS, DEXTRA, DCS and XLX ). There is no need for a hotspot. Just connect your ICOM IC-705 to your Windows PC with an USB datacable and connect it to your favorite DSTAR reflector/repeater.

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.

OpenRepeater is a low cost, low power, but feature rich duplex repeater controller suitable for setting up a temporary / emergency repeater systems with radios that can be run on portable power. Download the latest OpenRepeater software for your Raspberry Pi 2/3/3B+/4. This image contains everything you need to get up and running quickly.

supports three repeaters in the Florence SC area. The Club Callsign, W4ULH authorized by the Federal Communications Commission.

The **Arlington Amateur Radio Club** (K5SLD) website details club activities, including a weekly Taco Tuesday net on their 147.140 MHz repeater with a 110.9 Hz PL tone. The club, organized in July 1955 by 22 hams, also hosts monthly dining events and promotes Community Emergency Response Team (CERT) training through the Arlington Fire Department. Membership renewal information for 2026 dues is prominently featured, with an online payment option and a donation button available on the "Pay Dues" page. Club communications extend to a dedicated Facebook page for members and the wider amateur radio community. The site lists upcoming contests and encourages participation in local events. The 2-meter repeater net is open to all, fostering local camaraderie and technical exchange among hams in the Arlington, Texas area, regardless of club affiliation.

Old Cars and Amateur Radio. This club has a repeater on site of the World Longest Running car cruise. Part of the ARRG.US network

Live Audio Feed of the KI4FVI repeater in henry county Georgia

Presents the Bullitt Amateur Radio Society (BARS), KY4KY, detailing its organizational structure, meeting schedule, and operational activities. The resource outlines regular club meetings held on the second Tuesday of each month at Pioneer Village City Hall, providing specific dates for upcoming gatherings in March and April 2026. It also highlights the weekly BARS 2-Meter Net operating on 146.70 MHz, noting its suspension on meeting nights, and provides information on the club's participation in W1AW/4 operations for Kentucky, including specific UTC time slots for March 2026 and a contact for coordination. Details for becoming a member, contributing to the repeater fund, and joining the email list are available through quick links. The resource also offers practical information for prospective hams, such as exam test locations and BARS dues. It includes directions to the meeting location at Becknell Hall (Pioneer Village City Hall) from I-265 and Preston Highway, specifying the address as 4700 Summitt Drive, and mentions the club's presence on Facebook for activity updates.

Details the Big Thunder Amateur Radio Club (BTARC), a long-standing amateur radio organization based in Boone County, Illinois, established in 1962. It covers the club's mission to enhance the skills of local hams, promote radio knowledge, and foster social interaction among operators. The resource outlines BTARC's commitment to community service, including emergency communications support through RACES, and its active participation in events like Field Day, fox hunts, and public service communications for local races. Explains the club's history, including the establishment of its first repeater in the 1970s by members WD9JGH, Mike George, K9ORU, and Claude Horsman, WB9PMM, using a VHF Engineering kit and a Sinclair duplexer. It provides specifications for two club-maintained FM repeaters: a 2-meter repeater on 147.375 MHz (+600 KHz shift, 100.0 Hz PL tone) and a 70-cm repeater on 442.825 MHz (+5 MHz shift, 114.8 Hz PL tone). The club hosts a weekly 2-meter net on Sundays at 7:00 PM local time and holds monthly meetings on the second Thursday at the Spring Township Building in Belvidere, IL.

Amateur radio repeaters extend communication range for mobile and remote stations by retransmitting signals on a different frequency, often for emergency communications. The resource details various repeater bands, noting that 2 meters and 70 cm are primary for activity, with 10-meter repeaters offering potential national and overseas coverage. It specifies **18 channels** on 6 meters and **31 channels** on 2 meters, along with a new 70 cm offset of _7 MHz_ adopted in 2015. The content explains how repeaters can be linked via dedicated transmitters/receivers, landlines, or Internet VoIP systems like _IRLP_ and Echolink, enabling global connections. It also describes simplex gateways for multi-band operation and the use of CTCSS subaudible tones for access control and interference mitigation. The document highlights specialized repeaters for modes beyond voice, such as SSTV and ATV, particularly on 70cm and higher bands. Operational guidelines for efficient and courteous repeater use are referenced, along with links to Australian repeater listings and band plans.

SARA, the Schuylkill Amateur Repeater Association located in central-eastern PA in Schuylkill County.

The VU2BBB repeater, located in Matheran, Maharashtra, commenced operations in the late 1980s, a significant undertaking by the Bombay Repeater Society. This repeater facilitates VHF and UHF communications for local amateur radio operators, providing extended range and improved signal reliability across challenging terrain. Its establishment marked a key development in regional amateur radio infrastructure, offering a crucial node for local nets and general QSO traffic. The repeater's operational parameters include specific input and output frequencies within the 2-meter band, typically utilizing a standard offset. CTCSS tones are often employed to mitigate interference and ensure selective access for authorized users, a common practice for repeaters in densely populated areas. Regular maintenance and upgrades ensure _VU2BBB_ remains a reliable asset for the amateur community, supporting emergency communications and daily amateur radio activities. The _Bombay Repeater Society_ continues to oversee its operation, reflecting a sustained commitment to local ham radio services.

Fostering community spirit and recognizing contributions within amateur radio clubs often involves tangible tokens of appreciation. **Challenge coins** have emerged as a popular and effective method for achieving these goals, providing a unique way for clubs to acknowledge member participation and milestones. These custom-designed coins can reflect a club's specific identity and achievements, serving as a physical representation of membership and dedication. Clubs can utilize these coins for various purposes, including recognizing membership renewals, commemorating event participation like Field Day, or even as a fundraising mechanism to support club activities and repeater funds. The customization options extend to plating and color, allowing for different tiers of recognition, such as bronze for general membership, silver for life members, or gold for special awards presented by club officers. This flexibility makes them a versatile tool for enhancing engagement. Beyond traditional amateur radio clubs, organizations like the **Military Auxiliary Radio System (MARS)** also benefit significantly from challenge coins, reinforcing their connection to the broader military and amateur radio communities. The production process is simplified with artwork assistance, ensuring clubs can easily bring their unique designs to fruition.

Brugtgrej presents a Danish online classifieds platform specifically for amateur radio operators and electronics enthusiasts. The platform facilitates the buying and selling of used equipment, including transceivers like the Icom IC-7410, various components such as X'TAL FILTER FMT-15A and TRANSISTOR 2SC3019, and accessories like Sadelta microphone capsules and SMA to SMA extenders. Users can post free advertisements for items they wish to sell or acquire, covering categories beyond amateur radio, including antique radios, military radios, and radio tubes. The site lists active advertisements, with 3136 online ads and 167 online users at the time of analysis, indicating a dynamic marketplace. It also features a forum for community interaction, discussing topics like repeater rings on 1297 MHz and FT8 activity. The platform's structure supports both 'Sælges' (for sale) and 'Købes' (wanted) listings across its various sections. Specific items observed include a Miniwatt pentode 4689, various capacitors and coils, and general electronic components, demonstrating the breadth of offerings available to the amateur radio community.

The K7ICU repeater system is situated about 500' above metro Tucson, at the base of the Catalina Mountains. It is an open system providing coverage to the greater Tucson area.

The Kitchener Waterloo Amateur Radio Club (KWARC) website provides a central hub for its members and the broader amateur radio community, detailing club activities, meeting schedules, and special events. It features a monthly newsletter, the _Kilowatter_, which archives club news and technical articles, offering insights into local amateur radio operations and projects. The site also includes information on the club's repeaters, operating on various bands, and details about the annual _Central Ontario Hamfest_. Content covers diverse aspects of the hobby, from general interest articles to specific technical discussions. The resource serves as a primary communication channel for KWARC, facilitating member engagement and disseminating information about club-sponsored activities like field days and public service events. It also lists contact information for club executives and provides resources for new licensees.

Over 1900 ARISS school events have been conducted since 2000, facilitating amateur radio contacts between students and ISS crew members. This resource details the Amateur Radio on the International Space Station (ARISS) program, outlining scheduled contacts, operational procedures, and application processes for educational institutions worldwide. It lists specific upcoming contacts, such as those with Lewis Center for Educational Research in California and Vauban, Ecole et Lycée français de Luxembourg, typically operating on a 145.800 MHz downlink frequency. The content also provides crucial guidelines for radio amateurs, emphasizing the importance of not interfering with scheduled school contacts and utilizing the crossband repeater for general QSOs when available. It clarifies crew availability for casual contacts, noting that astronauts are usually free during personal time, approximately one hour after waking and one hour before sleeping, and often on weekends. Constraints on scheduling, such as avoiding EVA weeks and specific crew rest periods, are also detailed. Furthermore, the resource includes historical statistics on direct versus telebridge contacts, QSL information, and links to related ARISS, AMSAT, ARRL, and NASA websites. It also provides information on applying to host an ARISS contact for schools and youth organizations in various regions, including the United States, Europe, Africa, the Middle East, Canada, Central and South America, Asia, and Australia.

An Google Maps interactive layer showing Australian amateur radio repeaters. You can navigate and zoom as required and click on a repeater-site icon to display frequency, ctcss and other details and notes for that repeater.

The Milwaukee Repeater Club is the oldest continuously operating repeater in Milwaukee

The Contra Costa Repeater Association operates the WA6HAM VHF amateur repeater serving the San Francisco and Sacramento California areas. It was established in 1977.

The Yukon Amateur Radio Association has a series of 11 repeaters located throughout the territory, that are all, except for Watson Lake, linked together.

Wood County Amateur Radio Club (WCARC) serving Northwest Ohio. Meeting information, newsletter, repeater list, and resources for Hams in Northwest Ohio.

Stamford Amateur Radio Association Repeater Club. Located in Stamford, Connecticut.

Sixty-meter repeaters typically use a 1 MHz frequency separation between input and output, while 2-meter repeaters commonly employ a **600 kHz** split and 70-centimeter repeaters use a **5 MHz** offset. This article details the fundamental technical principles of amateur voice repeaters, explaining how they extend VHF/UHF communication range by receiving on one frequency and simultaneously retransmitting on another. It covers essential components such as receivers, transmitters, filters, and antennas, often situated on elevated locations for optimal coverage. The resource delves into the critical challenge of _desensing_—where the repeater's strong transmit signal overpowers its own receiver—and the engineering solutions employed, including antenna separation and the use of high-Q cavity filters. It also explores various control and timing systems, from basic squelch activation to more sophisticated microcontroller-based boards that manage functions like voice identification, time-out timers, and fault protection. Different access methods are discussed, including open access, toneburst, CTCSS subtone, and DTMF, each offering distinct advantages for managing repeater usage and mitigating interference. Furthermore, the article examines repeater linking, both conventional RF methods and modern internet-based solutions, highlighting how linking expands coverage and promotes activity across multiple repeaters or bands. It introduces less common repeater types such as 'parrot' repeaters, which use a single frequency and digital voice recording, and linear translators, capable of relaying multiple signals and modes simultaneously across different bands, often found in amateur satellites.

The Eastman Amateur Radio Club (VE4TG) operates a **VHF repeater** at 146.73 MHz and a **UHF repeater** at 444.15 MHz, both located at the Manitoba Hydro gas-fired generating station near Selkirk. These repeaters are situated on the power plant roof, leveraging its infrastructure for antenna placement. The club's primary objective is to offer a reliable local repeater site for members in the East Selkirk and Lockport areas, ensuring consistent amateur radio access. Beyond routine communication, the club maintains a standby communications link to assist local municipal authorities during emergencies requiring communications support. The unique repeater site location at a generating station provides a robust backup power supply, enhancing reliability. The club also organizes activities such as a weekly net and participates in WARC Field Day, fostering community engagement and operational readiness.

Pine Valley Repeater Amateur Radio Club Richland County ARES/RACES Serving Richland County with Sky warn Storm spotters and communications were needed. Working with Emergency Management and other emergency services.

The Hermiston Amateur Radio Club evolved from an informal coffee break in the late 1970's. The group met to discuss amateur radio topics and to support the 147.03 repeater. It was located at Ernie Netter's on Loop Road.