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Presents _Henry Radio Inc._ as a manufacturer of solid-state RF power amplifiers, detailing their capabilities across HF, VHF, and UHF bands. The company designs and builds custom amplifiers tailored for various applications, including amateur radio, commercial broadcasting, military, scientific, and industrial uses. These amplifiers are manufactured in the USA, emphasizing domestic production. Beyond amplifier manufacturing, the resource highlights Henry Radio's role as a distributor for _Bird RF Test Equipment_, including wattmeters, dummy loads, and attenuators. It also mentions _Tohtsu Coaxial Relays_ and a range of miscellaneous amplifier parts and electronic accessories, providing a broader scope of communication equipment offerings. Additionally, the site describes a trunking two-way radio system operating on the 450-476 MHz band, covering significant portions of Los Angeles and Orange County. This service caters to professional dispatch needs for ambulances, taxis, and other commercial entities, requiring no long-term contracts.

manufactures and distributes HF, VHF, UHF and SHF equipment covering 10MHz. - 47.0GHz. Our products include: Wireless LAN / WAN Bidirectional Linear Amplifiers, Low Noise Preamplifiers - LNA's, RF Linear Amplifiers, Relays, Transverter Systems, Frequency Translation Systems, Downconverters, Antennas, Parabolic Dishes, Coaxial Cable, Relays, Antenna Switches, Microwave Test equipment, PC controlled Receivers, Microwave Linear Amplifiers including models for Telemetry, Wireless, and CDMA applications.

A 40-meter reversible _Moxon rectangle_ antenna project details its construction and performance, featuring 51-foot long sides and 7.7-foot turned-in sections. The design incorporates a 16.5-foot boom, with elements spaced 1.1 feet apart, constructed from #14 covered wire. It utilizes two double-pole relays for switching between NE and SW directions, achieving F/B ratios up to 40 dB on CW and 30 dB on SSB, with distinct reflector stub settings for each mode. This antenna replaced a full-size 2-element Yagi, demonstrating comparable forward gain while offering superior F/B ratios and directional flexibility. _EZNEC_ modeling indicates only 0.2 dB less forward gain than the Yagi. The system uses no baluns, relying on half-wave feedlines and switched stubs for impedance matching. The antenna is tree-supported at 45 feet, with its effective radiation height modeled at 80 feet due to local terrain, enhancing its performance over a nearby lake.

The W1TAG LF Receiving Loop is a specialized antenna project for LF reception, designed to mitigate local noise and enhance weak signal pickup on the lower frequencies. This square loop, measuring 6 feet per side, utilizes 14 turns of #12 THHN wire wound on a PVC frame, offering a robust mechanical structure. The design incorporates a series-tuned circuit with a coupling transformer, allowing for tuning from over 400 kHz down to _45 kHz_ using a switched capacitor bank. Construction details include the use of 1.5-inch PVC pipe for the frame, with specific measurements for spreaders and drilled holes for wire threading. The two 7-turn sections of wire are connected at the center, providing an option for a center tap. The loop rotates on a 1-inch steel pipe, enabling directional nulling of noise sources. The tuning unit, housed in a box clamped to the PVC, employs a 1:2 step-up transformer wound on an _FT-82-77 core_ and uses relays to switch capacitance values from 50 pF to 6400 pF, providing precise frequency adjustment. The current setup connects to the shack via 100 feet of RG-58, feeding into a W1VD-designed preamp, with plans for a balanced, shielded twisted pair cable upgrade.

This project outlines the construction of a 3-element reversible quad antenna specifically designed for the 40-meter band. The materials required include pushup towers, pressure-treated posts, insulated wire, and various electrical components such as relays and a balun. The construction process is straightforward, beginning with the installation of the posts in a straight line, followed by the assembly of the antenna elements and their elevation to the desired height. The antenna's design allows for directional signal reception, making it ideal for operators looking to enhance their communication capabilities on the 40-meter band. The project includes detailed instructions on tuning the antenna for optimal performance, ensuring that operators can achieve the lowest SWR possible. Additionally, the design can be adapted for other bands by extrapolating dimensions, providing versatility for amateur radio enthusiasts. Overall, this reversible quad antenna project is suitable for both beginners and experienced operators, offering a practical solution for improving signal strength and directionality in 40-meter communications.

A great source for hard to find HI END & power tubes & sockets, various capacitors, vacuum relays, various keys and paddles.

A 90-foot vertical antenna constructed from **aluminum irrigation tubing** is detailed, focusing on its innovative raising and lowering mechanism. The resource describes a **45-foot ginpole** system, allowing a single operator to erect or lower the antenna in minutes. It covers the mechanical design, including the pivot base, insulated joints for the tubing sections, and guy wire attachment points. The antenna consists of two 30-foot sections of 4-inch tubing and one 30-foot section of 2-inch tubing, stacked with the smaller diameter at the top. The electrical design incorporates PVC "condulet" boxes at the 30-foot and 60-foot points, housing relays to change the effective height for multi-band operation on 160, 80, 40, and 30 meters. Ferrite rod inductive chokes are used for DC control and to tune out gap capacitance. The antenna is fed with 1000 feet of open wire line, connected to a matching transformer comprising stacked toroids and a coaxial/toroidal balun. Grounding is achieved with a 3x3 foot grid of 16-gauge tinned copper wires with soldered crossovers.

BIRD RF power measuring, new and used, HENRY RF power amplifiers (used HF amps), TOHTSU coaxial relays, SAMLEX power supplies, RFI chokes reduce interference, Parts parts, tubes, Used amplifiers, radios, antennas and accessories, Los Angeles, CA.

An interesting article with many technical details on a phased delta loop array for 80 meters band includes pictures of antenna relays

SSB-electronic gmbh based in Germany produces coax cables and connectors, rf parts and components, SDR receivers and transceivers, transvertes, attenuators, coax relays, precision directional couplers.

A project of a 5 Antennas Relay Switch Box, all Switches & Relays have both contacts wired in parallel to improve reliability of operation, to prevent static build up, when an antenna is not in use the feeder coax is grounded.

Demonstrates how to construct an automatic band decoder, moving beyond manual selector switches for antenna and filter control. It addresses the challenge of varying band data outputs from different transceivers: Icom rigs provide voltage values, Yaesu rigs use Binary Coded Decimal (BCD), and Kenwood rigs lack direct band data output. The resource highlights a clever solution utilizing logging software like _CT (K1EA)_ and _DX4WIN_ to emulate Yaesu's BCD output via a PC's printer port, making the decoder compatible with any rig. The author details experiences building decoders based on designs by Bob _K6XX_ and Guy _ON4AOI_, noting K6XX's simple TTL chip design and ON4AOI's more comprehensive, opto-isolated unit capable of controlling ten outputs and bandpass filters like the _Dunestar_. It also references a _W9XT_ board design, which Steve Wilson, G3VMW, modified with BD140 transistors for source drivers, emphasizing safety. The author successfully cased an ON4AOI-based decoder in an old modem case, connecting it to an FT1000MP or a PC printer port to drive remote relays and a Dunestar Band Pass Filter.

To build a Band Decoder to drive our remote relays, we need to supply the band information from the rig to the decoder

Demonstrates the construction and implementation of a **two-element phased vertical array** for 40 meters, utilizing _Christman phasing_ techniques. The author, W4NFR, details the process from building individual 1/4-wave aluminum verticals to integrating them into a phased system. The resource covers antenna spacing of 32 feet, elevated radial design, and the critical steps for tuning each vertical to achieve a 1.1:1 SWR before combining them. It also provides insights into calculating precise coax lengths for feedlines and the phasing delay line, emphasizing the use of an MFJ-269 Antenna Analyzer for verification. The finished system exhibits good front-to-back nulls, with an overall SWR ranging from 1.6:1 to 2.2:1, which is managed by an antenna tuner. The project includes detailed photos of the relay box, showing 12 VDC relays capable of handling 5KV, and the control box in the shack for switching between three different antenna pattern configurations. Static bleed-off chokes are incorporated for protection, and the construction emphasizes robust weatherproofing for outdoor elements.

RF-and Microwave Coaxial switches and relays

Demonstrates various practical amateur radio projects and technical discussions through video episodes. One episode details cutting and retuning a _1/4 wave shorted stub_ from 101.7 MHz to 107.5 MHz to safeguard a transmitter's driver stage, alongside insights into advanced _160-meter antenna systems_ like eight-circle arrays and beverage antennas. Another segment covers upgrading firmware on an _ATS-20+_ receiver using AverDudes for improved display and functionality, and a detailed guide on using D-Star DR mode on an _ICOM ID-52A_ for international repeater programming. Additional content includes a deep dive into _OpenHamClock_ as a potential replacement for the HamClock project, updates on _Raspberry Pi 5_ running Trixie OS, and a review of the Choyong LC90 Internet radio with AI integration. The series also features "Ham College" episodes, which meticulously prepare viewers for the Technician Exam by covering topics such as antenna and transmission line measurements, SWR interpretation, and the functions of basic electronic components like rectifiers, relays, and transistors. Practical advice on coaxial cable characteristics, dummy loads, and proper soldering techniques is also provided.

Several HD video overlay devices are offered, including the GeoStamp HD, which overlays GPS latitude, longitude, heading, speed, altitude, date, time, and depth onto AHD, HD-TVI, and HD-CVI (720p/1080p) video sources. The VideoStamp HD allows user-defined text overlays on similar HD video inputs, while the VideoStamp Keyboard HD enables text input via a PS/2 keyboard for video overlay. For commercial applications, the PostMark HD integrates with cash registers and POS terminals to overlay transaction data onto security camera feeds. Beyond HD video solutions, the DTMF-8 DTMF Decoder provides remote control capabilities for up to eight devices or relays using touch tones from a radio or other audio source. This decoder supports four operational modes and includes password protection, storing all settings in non-volatile EEPROM memory. The product line also includes standard definition OSD, RS-232, GPS, and POS text inserters, along with various DTMF encoders and DVR solutions.

Distributor of electronic components like diodes Transistors Microcontrollers Microprocessors connectors, switches, relays, integrated circuits, eproms, leds

Article describes a circuit that accelerates the coil of DC relays by momentarily doubling their voltage.

Relays, controllers, power meters, fault recorders, power sensing products

RF Coaxial Relays from stock is the answer to your urgent small quantity needs.

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.

GREENSTONE USA leader in the Vacuum Industry manufacturing products such as Vacuum Tubes, Vacuum Capacitor, Vacuum Relays, Vacuum Contactors and Vacuum Interrupters.

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.

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.

HAM-made engineering products supplies and produces coaxial relays, antenna switches, sequencers, roller inductors, variable capacitors, low noise preamplifiers, RF power rotary switches and coil bodies.

The Intercontinental Amateur Traffic Net (Intercon) operates daily on 14.300 MHz, providing a platform for emergency communications and facilitating third-party traffic among amateur radio operators. Established in 1960, the net aims to foster goodwill and friendly relations within the ham community. It operates from 0700 to 1200 Eastern Time, with a focus on monitoring emergency traffic while encouraging operators to maintain a distance of at least 5 kHz to avoid interference. All licensed General Class operators and above are welcome to check in, using standard phonetics for clarity. The net features rotating Net Control Station (NCS) operators every hour, ensuring a diverse range of voices and experiences. Operators are encouraged to provide relays and assist with emergency traffic when necessary. While there is currently no membership for non-NCS operators, opportunities exist for those interested in becoming NCS operators. The net emphasizes professionalism and courtesy, making it a valuable resource for both emergency communications and casual check-ins.

DXSPOTS is a Telnet connection program. It allows radio amateurs with a lot of DX traffic to know instantly the status of the bands and to know which DX are currently on the air. Following the Packet-Clusters where data was transmitted on VHF/UHF via dedicated relays and sometimes on HF at a very low speed (300Bds on HF), the Internet has taken over and is now transmitting DX information via the computers in most shacks. Translated with www.DeepL.com/Translator (free version)

An Arduino Based Antenna Switch For The IC-7300 that monitors the band voltage from the rear accessory socket on the IC-7300. Two RF antenna relays are used to switch to the appropriate output.

Over 1000 _Elecraft_ KX2 owners have benefited from the Kx22 Heatsink, experiencing cooler rig temperatures and higher output powers. PAE manufactures these heatsinks, along with AC power supplies for HF transceivers, remote power relays, and Ethernet relays, with all machined products manufactured in the **USA**. PAE distributes _Fair-Rite_ Mix 31 ferrite snap-it cores and toroid cores, essential for RFI suppression and impedance matching in amateur radio setups. The product line also includes commercial monitoring antennas, UQUI transformers, ULP AC power filters, and 3M conductive adhesive copper tape, catering to various station build-out and maintenance needs. The AM1 Portable Antenna Mount System and its AM1-VA Multi-Angle Adapter offer flexible antenna deployment options. PAE ensures careful packing of fragile ferrite products, with shipping cost adjustments communicated post-order for larger, heavier combinations to guarantee safe delivery.

This article details the design and construction of a compact 20-meter QRP SSB transceiver by Pete Juliano, N6QW, measuring just 2 x 4 x 2 inches—small enough for a shirt pocket. Inspired by a 1963 QST design and refined from a prior version, it employs bilateral circuits, a 4.9152 MHz homebrew crystal filter, switched-crystal VXO for 60 kHz coverage (14.160-14.220 MHz), and standard components like ADE-1L mixers and IRF510 PA for 1W output. Key innovations include a double-sided PCB skeletal frame for shielding and isolation, Vectorboard sub-assemblies, and ultra-miniature relays. The bilateral receiver/transmitter shares stages, omitting AGC for simplicity, while a W3NQN LPF and optional 10W external amp enable DX contacts. Tune-up focuses on crystal matching and bias for linearity. Videos on YouTube demonstrate performance, confirming excellent stability and audio. Total cost nears $100, prioritizing portability over features like CW.

The tri-band trapped delta loop antenna design operates on 80 meters (3.5–4 MHz), 40 meters (7–7.3 MHz), and 30 meters (10.1–10.15 MHz) using a single triangular wire loop. This configuration eliminates the need for an external antenna tuner or band-switching relays. The antenna's physical perimeter, approximately 270 feet, establishes 80M as the fundamental band, with specific trap placements enabling resonance on 40M and 30M. Trap design and placement are critical, with 30M traps positioned inboard of 40M traps within the horizontal element. Each slant leg measures approximately 80 feet. The resource references foundational information from the _ARRL Antenna Handbook_ and _ON4UN’s Low Band DXing_ regarding full-wave loop behavior and feedpoint impedances. The project aims to provide multi-band HF operation from a single, fixed antenna structure.

This article provides an overview of setup Direwolf and QtTermTCP for HF packet radio operations. It covers important tasks such as setting up a Direwolf TNC, connecting with stations, and engaging in packet-based chat (K2K). It also looks at how to use nodes as relays and access basic BBS services. The paper also includes HF packet network etiquette recommendations and a description of how to handle common packet transmission issues, making it a useful resource for amateur radio enthusiasts.

The author describes building a remote switch box to control the direction of two reversible Beverage antennas. The switch uses a buried cable and relays to select the desired antenna direction from the shack. The design is simple and uses common components.

DF6QV's 4-Square antenna analysis begins with a two-element array simulation, demonstrating azimuth and elevation plots for various phase differences, including a 75-135 degree range. The document then delves into the core components of a 4-Square system, such as radiators, couplers, phasing lines, and ground systems, referencing W1HKK's 1965 QST article on an 80m phased array. It explores the influence of ground conditions and element spacing on antenna performance, presenting EZNEC analysis for an 80m 4-Square with an elevated radial, showing how gain and beamwidth vary with spacing. Various 90-degree couplers, including the 3 dB hybrid coupler and the Reed Fisher coupler, are analyzed using LTSpice, detailing power splitting, phasing, and bandwidth characteristics. The resource quantifies power, voltage, current, and losses within a 4-Square system, addressing relays, capacitors, inductors, radiator radial systems, and cable losses. System impedance, bandwidth, SWR, isolation, and mutual coupling are discussed with practical construction aspects covering common mode chokes, phasing boxes, and remote control systems. Field test observations for 40m 4-Square antennas are included, with specific examples from DXpedition operations like 5A7A and VP6DX, providing real-world context to the theoretical and simulated results.