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Two easy to build microcontroller projects for machine recognition of hand-sent morse code

This page describes a couple of parts box medicine bottle antennas that you can build. The ground side of the capacitor is soldered to the ground of the BNC connector. The positive side of the capacitor takes 5 turns around the toroid and is soldered back to itself. The center pin of the BNC connector takes 5 turns around the toroid and then continues on to the wire wound inductor. From there the antenna continues with an attached piece of wire.

Illustrates the fundamental principles of radio repeaters, detailing their role in extending communication range beyond line-of-sight limitations. It begins by defining _simplex communication_ as a direct radio-to-radio link, effective only when no obstructions impede the signal path. The resource then introduces the concept of a repeater (or base station) strategically positioned on elevated terrain, such as a mountain, to overcome geographical barriers. The article clarifies the repeater's operational mechanism: it receives a signal on one frequency and simultaneously re-transmits it on a different frequency, enabling users on opposite sides of an obstruction to communicate. This _duplex operation_ is likened to satellite communication for VHF propagation, but with a fixed terrestrial station. Specific examples of signal paths are provided, showing how a handheld radio transmits up to the repeater, which then relays the message down to another user, effectively bypassing obstacles like hills or large buildings.

David's blog dedicated to amateur radio operations

South Dakota Hams. The Pierre Amateur Radio Club homepage.

Handmade drawing of a 3 bands single loop, portable quad antenna used by the author during his dx pedition in Kenya as 5H3FM. This antenna is done using 3 telescopic spreaders and the spreader kit for 1 element quad by spiderbeam.

The Digital Communications Interconnect (DCI) resource details the operational philosophy and technical implementation of an open _MotoTRBO_ IPSC network, emphasizing the use of _c-Bridge_ technology for interconnecting DMR repeaters and talkgroups. It outlines the group's mission to facilitate dynamic connections within the regional DMR amateur radio community by openly sharing network resources and talkgroups, promoting independent network growth and exploring the capabilities of c-Bridge linking. The site provides insights into the technical advantages of c-Bridges, such as breaking the finite peer slot limitation of simple IPSC networks and enabling more flexible talkgroup routing beyond two timeslots. This legacy asset, last updated in October 2022, also reflects on the group's history and challenges encountered in national DMR efforts, citing political divisiveness among major c-Bridge groups. It discusses the practical application of c-Bridges for emergency communications and nets, ensuring redundant talkgroup servers for smooth day-to-day operations and priority events. The resource encourages other c-Bridge operators to adopt international talkgroups like "_iCall Talkgroup_" and a nationwide "Emergency Talkgroup," while also offering guidance on affiliating repeaters or IPSC networks with DCI's open network.

As a ham radio club we get involved with contest, emergency response and services (CERT, RACE, ARES & etc), volunteering to organizations that needs our help (Community, Boys Scouts, Senior Citizens, & etc.), promoting and educating individuals of amateur radio operations (ARRL, FCC, Obtaining Licenses, Local Government, & etc), meeting new and interesting people around the world and beyond through many sources (VHF, UHF, HF, Computers, CW, D-Star, RTTY, & etc.), amateur radio is a great social skill, there is no age limit on who can get involved, and much more.

Official web site of the Comox Valley ARC

CT Spectrum Management Association

W7GJ 6m EME DXpedition to Niue September 7-21, 2012 CQ DX Zone 32

Operaring portable during field day by VK4ADC

Steve Nichols, G0KYA, presents a practical examination of ground systems for vertical antennas, drawing heavily on the empirical research of Rudy Severns, N6LF. He explains that a robust radial field is crucial for ground-dependent verticals, effectively replacing the antenna's "missing half" and mitigating severe RF absorption in lossy soil. Nichols clarifies that surface radials do not strictly require a quarter-wavelength; instead, deploying a minimum of 16 to 32 shorter wires often yields superior results compared to fewer, longer ones. The presentation also addresses the common SWR paradox: a poor ground might show a perfect 1:1 match, but adding radials, while potentially raising the SWR to around 1.4:1, significantly improves true radiation efficiency. Nichols defines counterpoises as elevated wire networks that substitute for earth connections, offering solutions for limited-space installations, such as the **Folded Counterpoise (FCP)** for 160 meters. This resource provides actionable engineering data for optimizing vertical antenna performance.

This antenna is reported as being lower noise than conventional yagis and had a very low SWR for 500 KHz.

Picture and technical specifications of the Yaesu FT-8800R dual band transceiver

The Necessary Bandwidth for CW Signals By George Grammer W1DF

July 2013 DXpedition to Miquelon Op - Eric KV1J

NanoVNA based on edy555, use the odd harmonic extension of si5351 to support the measurement frequency up to 900MHz. GitHub repository.

Shipping cases, military cases, instrument cases equipment cases by Platt Cases

Manufacturer of two way radios based in Shenzhen China. Retevis produce commercial, personal and amateur radio handheld and mobile transceivers, either for analog and digital modes. Retevis produce also two-way radio accessories and repeaters.

Afghanistan 2011 dx pedition online log

With an eye to the final cost I have built a good 20 meter monoband Hex Beam antenna.

Curacao island by PJ2/DK5ON March 2014

A home made portable QRP transceiver designed to work on 40 or 80 meters SSB band.

Construction of an antenna for experimental satellite communication, 8el. (435 Mhz) x 4el. (145 Mhz) Satellite Yagi crossed. No difficulty to built this antenna. Except the gamma match. that requires a little more attention

The Straits Area Amateur Radio Club (SAARC) operates a 146.68 MHz (-) repeater with a PL tone of 110.9, serving Northern Michigan for emergency communications and community support. A temporary cross-band repeater on 445.875 MHz is also available during specific hours, enhancing local coverage. The club actively supports disaster services through its repeater infrastructure and coordinates local community events. SAARC provides resources for prospective hams, including information on licensing classes and testing sessions, and promotes amateur radio education. Members and interested individuals can join the club's Groups.IO group for updates and participate in the Bill DeMay _K8GUG_ Memorial Net, held weekly on Monday evenings at 8:00 PM on the primary repeater frequency.

Examines Teledyne Cable Solutions' offerings, focusing on their engineered solutions for demanding cable applications. The resource details their capabilities in designing and manufacturing _multi-core cable_ and ruggedized assemblies, emphasizing their integrated approach within Teledyne Marine. It covers the technical aspects of their products, which are tailored to specific operational environments and performance requirements, ensuring reliability in challenging situations. The content highlights the practical application of their cable solutions across various industries, including those requiring robust interconnectivity for remote sensing or communication systems. It implicitly suggests how these specialized cables, designed for high performance and durability, could benefit amateur radio operators seeking reliable feedlines or control cables in extreme weather or portable operations, potentially offering superior signal integrity and mechanical strength compared to standard offerings. The company's focus on custom solutions distinguishes its approach.

The Meteor-M N2 is a polar orbiting Russian weather satellite that was launched on July 8, 2014. Its main missions are weather forecasting, climate change monitoring, sea water monitoring/forecasting and space weather analysis/prediction. Meteor-M N2 transmits images using the digital LRPT protocol at around 137.1 MHz with can be received with an RTL-SDR.

Since January 1, 1982, 1A contacts have been eligible for **DXCC** credit, making the prefix highly sought after by the amateur radio community for over 41 years. The 1A0C station, operated by the Order of Malta's Italian Relief Corps (CISOM), engages in DXpedition activities with a dual purpose beyond simply providing a rare "new one" for DXers. For instance, the July 26 - August 2, 2023, operation specifically channeled received donations towards reconstruction efforts for flood victims in Romagna, aligning with CISOM's humanitarian mission. The site outlines CISOM's broader scope, which includes impartial humanitarian relief, medical assistance, and emergency support for natural disaster victims, emphasizing respect for diverse beliefs. This approach integrates high-profile amateur radio operations with significant charitable outcomes.

An omnidirectional horizontal polarization antenna for 2 meters band in Italian

This page by Keith Greiner describes a magnetic loop antenna project, providing step-by-step instructions to create two versions of a system with one large loop and one small loop. It includes details on how to construct the loops using different materials, along with the necessary equipment like antenna analyzers, tuners, and software. The page is divided into five sections covering project discussion, design summary, an improved small loop, construction steps, and radiation pattern analysis. Aimed at hams interested in building their own magnetic loop antennas, the page offers practical guidance and insights into impedance matching for improved performance.

N3UJJ's Ham Radio Web Site

A 30 cm antenna for the six meters band in japanese

The _RS Group_ (formerly Distrelec) provides a comprehensive online store for electronic components, catering to both industrial and amateur radio needs. This resource offers a wide array of parts, including semiconductors, capacitors, resistors, relays, sensors, and power supplies, essential for constructing and maintaining amateur radio equipment. The platform emphasizes efficient procurement and features various top-level categories for easy navigation, such as **Sensors** with 33 subcategories and **Relays** with 13 subcategories, supporting diverse project requirements. Beyond component sales, RS Group offers services like ISO- and DAkkS-certified calibration for over a thousand measuring devices, and e-procurement solutions for businesses. The site also promotes _DesignSpark_, a community and software suite for electronic designers, aiding in the realization of design ideas. This integration aims to provide enhanced local support and a broader product selection, facilitating everything from basic circuit builds to complex industrial automation projects.

Finding the the best ferrite material for a common-mode choke. How to create efficient ferrite cores and how to measure them

The original HEXBEAM was developed by Mike Traffic, N1HXA, in the early nineties. It is true that an M over W configured yagi antenna that resembled a butterfly was earlier tried successfully. But the advanced electrical design, the characteristic nesting concept and central terminal post that enable the multi band functionality along with the basic hardware design were all developed by Mike Traffie.

2 to 8 May 2010 with JG7PSJ(JD1BMH) and 8 to 14 Aug. 2010 with JI5USJ(JD1BLX)

Specialist for vertically adjustable supporting frameworks including telescopic masts and telescopic towers for ham radio systems, lighting systems, measurement techniques, observation systems. Located in Gnaschwitz Germany

A log utility for WSJT-X and JTDX Provides functionality missing from WSJT-X and JTDX and more

There are several ways to reduce the length of a dipole and still use it as an effective antenna. Remember it is the electrical length that determines resonance. The physical length can be considerably less than a half wave length on your desired frequency as determined by 468/f MHz.

This antenna mast mount uses two Reese hitch extensions that are welded on to a piece of 2 inch square tube. It comes apart in two pieces. The vertical pipe on the left is welded on to a 2 inch piece of square tube that fits into the Reese hitch extension.

How to use AI (Artificial Intelligence) to identify Radio signals using a RTL SDR dongle and Linux (Ubuntu). This solution implement a framework using Keras and TensorFlow to learn and recognize the RF signals.

TelExpress provides a wide array of RF and data connectivity products, including various coaxial cables like LMR-series equivalents, fiber optic cables, and Ethernet solutions. Their inventory supports diverse amateur radio and telecommunications requirements, from antenna feedlines to network infrastructure. The site emphasizes bulk cable availability and custom assembly services, catering to both individual hams and larger installations. Key offerings include _low-loss coax_ for HF and VHF/UHF applications, along with a comprehensive selection of RF connectors. They also supply patch panels, Ethernet cables (Cat5e/Cat6), and general wireless and telecom hardware. Customers can find components for building robust station infrastructure, ensuring signal integrity across various frequency bands. The platform facilitates procurement of essential parts for new builds or upgrades, supporting reliable RF system performance.

Choking balun for lower HF and MF bands. (1.8MHz - 10MHz). Requiring a choking balun to isolate the potential RF pick up on the coax cable as it runs past equipment such as computer within the radio room at lower HF and MF frequencies a simple method of winding RG58 coax onto a Powdered Iron Toroid Core was constructed.

Remote Orbitron enables either direct connection between a computer and the shack unit using a serial port OR remote operation from the internet using a WIZ110SR serial to ethernet board.

Article about Standing-wave ratio (SWR) defined as a mathematical expression of the non-uniformity of an electromagnetic field on a transmission line. SWR is the ratio of the maximum radio-frequency (RF) voltage to the minimum RF voltage along the line.

Passive Bandpass Filter online calculator and filter formulas. Active Inverting Op Amp Bandpass Filters, Active Noninverting Op Amp Bandpass Filter, just enter the Low ir High Cutoff Frequency

Amateur Radio club in Central Utah

Explore two magnetic loop antenna constructions, utilizing a 6-foot and a 12-foot square loop. Accompanied by a detailed description, the 6-foot loop features a built-in stepper motor control circuit, while the 12-foot loop incorporates a separate loop controller. Efficiency, tuning ranges, and the innovative autotuning solution using a microcontroller are discussed, offering insights into overcoming the antenna's narrowband limitations.

The Michigan Area Repeater Council, Inc