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RF Feedline (Coax and Ladder-Line) Loss and ERP Calculators made with Javascript. This complex feddline loss calculator has already several line types paramenters for most common coaxial cables from Belden, Time LMR, Wireman and other common products. Result will give Matches loss, SWR loss, dB and Watts power loss.

Demonstrates the practical application of APRS (Automatic Packet Reporting System) through the lens of HB9PVI's activities in Switzerland. It covers the system's core function of reporting geographical positions and telemetry data from various objects, including mobile stations, aircraft, and the ISS, distributed via packet radio and internet gateways. The resource highlights the routing paradigm shift introduced in April 2005, specifically the recommendation to use _WIDE1-1_ instead of RELAY and WIDE for digipeating to reduce duplicate packets. The page presents real-time maps displaying the positions of amateur radio stations in Switzerland and around Bern, updated every few minutes. It details specific callsigns like _HB9BA-2_ (HB9PVI's home QTH), _HB9BA-8_ (a weather station), and _HB9BA-4_ (a WIDE digipeater on Weissenstein mountain), providing context for their roles within the local APRS network. Links to track HB9PVI's mobile operations (_HB9PVI-9_) and handheld devices (_HB9PVI-15_, _HB9PVI-7_) are also provided. Furthermore, the resource curates a list of APRS software options for various operating systems, including _JavAPRS_ for Europe, _UI-view_, and _X-Astir_ for Linux, alongside digipeater/IGATE software like _DiXPRS_. It also offers downloadable APRS information, including a PDF article by HB9PVI and HE9ZGN, and a PowerPoint presentation in German, making it a repository of practical and historical APRS data.

An article on origin and usage of the Decibel, that has always been a logarithmically based representation of a power ratio

Schematic drawing and instructions for the construction of a simple portable dipole for use in low power and portable operations

DC filters from radius power are specifically optimized for applications with DC supply like e.g. photovoltaic inverters. Radius Power provides total power solutions, EMI filters solutions from design to manufacturing, Three Phase, Single Phase, Power Line, IEC inlet, Power entry modules Filters.

Operating in a Single Operator Two Radios (SO2R) setup, especially with beverage antennas, often exposes the receiving radio's front-end to significant RF energy from the transmitting radio. This resource details a practical, homebrew receiver protection circuit designed to mitigate this risk. The core of the design involves a non-inductive 2W 22 Ohm carbon composition resistor in series with the RX antenna line, followed by two stacks of four fast-switching diodes (e.g., _1N914_) configured in opposite polarizations. This arrangement effectively clamps the incoming voltage to approximately 2.8 V peak-to-peak, safeguarding sensitive receiver input components. The series resistor plays a crucial role by absorbing excess power, preventing the diodes from exceeding their current ratings and potentially failing open, which would leave the receiver unprotected. The author, _N4KG_, measured up to 50 watts of coupled power between 80M slopers on the same tower, highlighting the necessity of such protection. The design is presented as a cost-effective solution to prevent damage to receiver input transformers, with the author noting successful protection of a receiver even after a resistor showed signs of overheating. This simple circuit can be integrated via a transverter plug, offering a robust defense against high RF input.

The Terminated End Fed Vee Antenna (TEFV) is a travelling wave antenna with constant current distribution. Unlike traditional resonant antennas, TEFV operates without standing waves, using a terminating resistor for broadband efficiency. With a combination of vertical and horizontal polarization, it offers wide bandwidth from 1.8 MHz to 30 MHz, eliminating the need for a tuner. Key components include a 9:1 unun transformer and a 500-ohm terminating resistor. Grounding and counterpoise enhance performance, and it can handle power losses of up to 30%. TEFV provides an effective, versatile antenna solution for amateur radio and broadcast applications.

Bird 4314 RF Power Meter Battery Replacement

High Speed Multimedia (HSMM) radio, as introduced by John Champa, K8OCL, represents a significant advancement in amateur radio's digital capabilities, moving beyond traditional keyboard modes like packet radio. This initiative, driven by ARRL's Technology Task Force, focuses on developing high-speed digital radio networks capable of up to 20 megabits per second. HSMM primarily facilitates digital voice (DV) and digital video (ADV), enabling real-time video transmission from emergency scenes to an EOC without expensive ATV gear, often requiring only a laptop, a PCMCIA card, a digital camera, and a small antenna. The working group's initial efforts concentrate on cultivating microwave skills within the amateur community to build and support portable and fixed high-speed radio-based local networking, or **RLANs**. These networks prove invaluable for RACES and ARES organizations, as well as homeland security and other emergency communications. Field Day exercises and simulated emergency tests (SETs) are encouraged to hone skills in rapid site surveys and deploying broadband HSMM microwave radio networks, with examples like linking Field Day logging stations or antenna test results at the Midwest VHF-UHF Society Picnic 2003. Getting started with HSMM often involves adapting off-the-shelf **IEEE 802.11** (WiFi) equipment to comply with amateur radio regulations, typically operating in the 2.4 GHz ISM bands. While consumer WiFi gear has range limitations under Part 15 rules, proper setup under amateur regulations can extend coverage significantly, with test networks like the Hinternet achieving 5-15 mile ranges at 54 M bit/s using small mast-mounted dish antennas. Careful selection of equipment with external antenna ports, high transmit power, and low receive sensitivity is crucial, along with using low-loss coaxial cable like LMR-400 for optimal performance at these frequencies.

28.222mhz transmitting with 2 watts of power

Have you been looking for an easy way to measure power or SWR at 1296 MHz? One thing is certain, it is not easy - simply because the normal range of SWR meters that most of us have is not up to 1300 MHz.

Voldatech, a manufacturer based in China, produces a range of RF feeder cables and site components essential for amateur radio installations and telecommunication infrastructure. Their product line includes various types of coaxial cables, such as **50 Ohm** and 75 Ohm options, along with a comprehensive selection of connectors like N-type, UHF, and BNC. These components are critical for maintaining signal integrity and minimizing loss in antenna systems, whether for a home shack or a remote DXpedition setup. The company's focus on _RF Coax cables_ and connectors directly supports the needs of radio amateurs seeking reliable transmission lines for their transceivers and antennas. Amateurs often compare Voldatech's offerings to established brands, evaluating factors such as impedance matching, shielding effectiveness, and durability under various environmental conditions. The availability of diverse cable types allows operators to select optimal solutions for different frequency bands and power levels, from QRP to high-power amplifier setups. Their products are particularly relevant for those constructing new antenna arrays or upgrading existing feedline systems, aiming to achieve maximum power transfer and reduce standing wave ratio (SWR) for efficient signal propagation.

DF0WD/DL4YHF's Longwave Overview details amateur radio operations on the 135.7 to 137.8 kHz segment in Germany. The author outlines the "inofficial" European band plan, specifying segments for QRSS, TX tests, beacons, conventional CW, and data modes. Early LF activities at DF0WD began with a 20-watt CW transmitter, later upgraded to a homemade linear transverter capable of 100 watts, driven by an Icom IC706 on 10.137 MHz. The station's antenna system includes a 200-meter wire, approximately 10 meters above ground, supported by football field light-masts. Despite its length, the antenna's efficiency is noted as very low due to the immense wavelength of about 2.2 km. The author's experience highlights the significant challenge of achieving effective radiated power (EIRP) on LF, estimating DF0WD's EIRP at around 80 milliwatts based on field strength measurements from PA0SE. DF0WD/DL4YHF has successfully worked numerous countries on 136 kHz CW, including DL, F, G, GI, GM, GU, GW, HB9, HB0, LX, OE, OH, OK, OM, ON, OZ, PA, and SM. The author also mentions ongoing efforts to log contacts with CT, EI, LA/LG, and to complete a two-way QSO with Italy, demonstrating persistent activity on this challenging band.

A HF power amplifier with a push-pull of AFT09MS015N. The (small-signal) gain of the amplifier is around 26 dB in the lower HF band and goes down to about 24 dB on the higher end and still around 21 dB at 50 MHz. Its input matching is relatively good at the lower HF and degrades above 10 MHz.

The WhereAVR is a small, lightweight, low-power, and low-cost APRS tracker with a full compliment of analog and digital I/O, as well as the ability to decode ax.25 packets. This allows for the reception of remote commands without the need for a real TNC.

A review of the Yaesu FT-8900r 29/50/144/430 MHz FM Transceiver, providing 50 Watts of power output on the 29/50/144 MHz Amateur bands, and 35 Watts on the 430 MHz band.

Tysonpower details a DIY AZ/EL antenna rotator project designed for under €150, inspired by the Satnogs Tracker. Constructed with 2020 aluminum extrusion and NEMA23 stepper motors, the rotator is controlled via an Arduino Nano. It effectively tracks smaller antennas like Yagi, though struggles with heavier dishes. STL files are available on Thingiverse.

DK7IH QRP transceiver for 14 MHz. This small and compact home made transceiver with a max power output of 5W, the VFO module is based on the clock oscillator chip Si5351A by Silicon Labs ATmega168 and OLED 1306

Crystal receivers are radio receivers that work without a power supply or batteries. Gallery of some crystal radio projects

Using portable battery power is always a challange when operatin amateur radio in sota oprations. This article is about implementing lithium iron phosphate cells (LiFePO4) in ham radio portable operations.

Over 500 different types of high-performance electronic cables are manufactured by Alpha Wire, catering to demanding industrial and commercial applications. Their product lines include the robust _XTRA GUARD_ series, designed for harsh environments, and a range of flexible coaxial cables optimized for signal integrity. These cables are critical components in amateur radio shacks, industrial control systems, and data communication networks, ensuring reliable power and signal transmission. The company provides extensive technical resources, including detailed product specifications, application notes, and RoHS certificates, accessible through their online resource center. Hams often utilize their wire and cable products for antenna construction, station wiring, and various DIY projects requiring durable and reliable conductors. Alpha Wire also offers tools like size guides and competitor cross-references, simplifying product selection. They emphasize continuous uptime solutions, reflecting their focus on quality and durability.

256 memories enable the _AT-AUTO_ to recall settings across multiple bands, making it efficient for operators who frequently change frequencies. The tuner is compatible with various antennas and amplifiers, such as the Mercury LUX, and integrates seamlessly with radios like the FLEX 6400 using an RS232-USB connection. This integration allows the tuner to follow frequency changes without additional input, enhancing operational efficiency. Despite being out of production, the _AT-AUTO_ remains supported by Kessler Engineering, which offers firmware updates and repair services. The tuner features a cross-needle SWR meter, providing quick visual feedback during tuning. It also includes a QRO keyline circuit to protect amplifiers during tuning. Users appreciate the tuner's ability to track radios via CAT control, avoiding automatic tuning during QSOs, a common issue with other models. The _AT-AUTO_ is praised for its durability and performance, with many users noting its reliability over years of use. Its ability to handle legal limit power and its balanced line output make it a versatile choice for serious operators. Although it lacks some features like multiple coax outputs found in other models, its robust build and continued support make it a valuable tool for HF enthusiasts.

Yamuna Cable Accessories Pvt. Ltd. specializes in the development, manufacturing, and marketing of power cable accessories, including a comprehensive range of cable jointing kits and components. The product line encompasses _Heat Shrink_ and _Cold Shrink_ cable joints, heat shrinkable tubing, pre-moulded slip-on joints, resin pour, and Tapex systems, all designed for applications up to 66 kV. The company highlights its ISO 9001-2015 certification, signifying adherence to international quality management standards in its manufacturing processes. The resource details specific product categories such as end caps, insulation piercing connectors, copper mesh, fireproof coatings, tubing and components, lugs and ferrules, and safety products. It also features specialized items like _Elbow Connectors_ rated for 25 kV-250, 400, and 630 amps, and various types of tinned copper braid used for grounding and electrical shielding. The site provides an overview of their manufacturing capabilities and global presence across 40+ countries. Established in 1973, Yamuna Densons has over four decades of experience in the industry, positioning itself as a significant designer, manufacturer, and supplier of insulators, tabs, and cable jointing systems in India. The company emphasizes its role as a leading exporter of these products, serving both domestic and international clients.

But it is only a couple of dB, The Effect Of Insertion Loss On Transmitted Power (dB to percentual loss) Original Information Provided by Neil McKie WA6KLA

A very small receiver converter that can be plugged to the backside of the battery powered portable transceiver FT817 from Yaesu. A high performance receiver for 2.3GHz amateur radio signal

A review of the Alpha 87-A power amplifier by WD0M

High Plate Voltages Reported via Telemetry on Alpha 8410 power amplifier by AE9K

I used a FT 240-43 for much more power, not needed but beter safe than sorry. 150 Watt continious, 300 Watt PEP SSB, 90 Watt Digimodes 10 Mhz, 18 Mhz, 24 Mhz Very easy to build design and a good antenna for people who don't have much space for big towers or long wires This design is from Hans - PE1RNU

Presents various amateur radio topics through blog posts, detailing operational experiences and technical insights from the perspective of SV2YC. The content frequently discusses antenna projects, such as a **portable 20m/40m dipole** designed for rapid deployment, and explores the performance characteristics of different wire configurations in varied field conditions. Observations on propagation and band activity across the HF spectrum are also regularly documented, providing practical context for fellow operators. Specific entries often include detailed accounts of **DX contacts** and participation in minor contests, outlining station setup, power levels, and antenna choices. The blog also covers modifications to commercial transceivers and homebrew accessory construction, offering practical advice on improving station efficiency and functionality. Further posts delve into software applications for logging and digital modes, sharing configurations and operational tips for maximizing their utility in daily amateur radio activities.

eHam reviews of the RM VLA 200 VHF RF power amplifier

Collection of several topics on antenna tuners and their performance. Why use an antenna tuner? How does an antenna tuner…tune Does an antenna tuner fool the radio? Will an antenna tuner waste power? Can an antenna tuner help get more power to the antenna?

Using DX4WIN with ICOM radios and the ICOM PW-1 RF power amplifier

Ham radio, amateur radio, satellite communication, radio, radios,antenna, antenna design, yagi, cross yagi, power divider, splitter, Brisbane.

This page details my building of a 100 Watt Power Amplifier for the 432 MHz Band based on two Motorola MRF646 transistors taking inspiration by Carlo Gnaccarini VK3PY, formerly VK3BRZ

A home made Antenna Tuner made with a simple inductor and a few spare parts. Despite the title, the author succesfully tested this ATU with higher power inputs.

Turning an RV marine battery into a massive 12-volt emergency power source

eHam reviews of Alpha 8410 HF power amplifier

Alpha 8410 power amplifier software monitor anc control functionalities description by AE9K

A distance of 1/8 lambda between the antenna and the vehicle roof is suggested for optimal performance, with slight adjustments possible to lower the take-off angle for terrestrial contacts. This resource details the adaptation of an _Eggbeater_ antenna for mobile use, specifically for VHF operation, leveraging the car's metal roof as a ground plane. It illustrates the mounting method, repurposing a magnetic ski carrier base, and describes the integration of coaxial relays for polarization reversal, a feature also applicable to UHF versions as discussed in "_Eggbeater Antenna VHF/UHF – Part 2_". This mobile configuration proves effective for satellite communications, such as through the International Space Station (ISS), while also maintaining strong performance for land-based radio contacts. The inclusion of switches with indicator lights for VHF and UHF polarization control, powered by the vehicle's battery, highlights practical considerations for field deployment. The system's adaptability for portable operations underscores its versatility beyond fixed mobile installations.

This device was designed as an SWR and power meter for Radio Amateurs. In addition to SWR, it measures forward and backwards power, therefore can also be used as a wattmeter. With a large measuring range from 1 to 1000 watts, it is suitable for use from QRP to QRO

An article on popular AL80 HF power amplifier manufactured by Ameritron since 1980

The DX FT8 is a compact, multiband tablet transceiver designed for FT8 digital mode enthusiasts. Supporting five or seven HF bands, it integrates an STM32F746-based touchscreen interface for standalone operation, eliminating the need for a PC. The latest firmware (v1.9.2) adds SOTA/POTA calling and free-text messaging. Its efficient power design, unique RF amplifier, and 3D-printed case enhance portability. Open-source firmware and community-driven development make it a versatile choice for portable FT8 operation, ideal for SOTA, POTA, and travel use. DX FT8 TRANSCEIVER PROJECT is a collaboration between Charles(Charley)Hill, W5BAA and Barbaros(Barb)Asuroglu, WB2CBA.

The Icom IC-PW1 is a 1000 watt linear amplifier with built-in power supply

This page describes an update to a project for a Power and SWR Meter for ham radio operators. The update includes a more powerful microcontroller, increased sampling rate, and improved display options. It explains how to use the new components and provides detailed instructions for building the updated meter. The page also offers alternative display options and includes the full source code for the firmware. Overall, this update enhances the functionality and performance of the Power and SWR Meter project, making it more versatile and user-friendly for hams looking to measure RF power and SWR in their radio setups.

A project by LY3H of a complete Scalar USB network analyzer with freeware windows software, sweep range 100 kHz to 160 MHz, powered by USB.

Learn all about FT8 and FT4 digital modes in ham radio. Discover how to configure software to use these powerful modes for making contacts even in poor conditions. Find out how to hunt for awards and view instant statistics of your transmissions. Explore the benefits of using digital modes such as FT8 and FT4 for enhancing your ham radio experience.

This is a great project to learn about the basics of electronics, batteries, and renewable energy. The finished project can charge a phone or tablet, light up a camp-site, and provide for whatever other small electric needs you have.

Configuring dxlab commander to properly control the Icom PW-1 power amplifier

An article by MicroHam on using the Icom PW-1 RF Power Amplifier safely and with non-Icom transceivers.

Many antennas and antenna designers neglect the true cause of loss. The major problem using short antennas is the reactance, not the length