Search results

Cubic quad antennas are renowned for their high gain, excellent front-to-back ratios, and low angles of radiation, making them a popular choice among amateur radio operators. This resource provides detailed designs for constructing cubic quads optimized for 2, 6, 10, 12, and 15 meter bands. The lightweight structure can be easily built using fiberglass tubes and central hubs, allowing for portability and ease of assembly. The article discusses the specific dimensions and configurations required for both HF and VHF applications, emphasizing the importance of proper spreader lengths and boom dimensions. It also highlights the challenges of assembling larger cubic quads in limited spaces, offering practical solutions for hams with smaller backyards. With a focus on multi-band operation, this guide serves as a valuable resource for both novice and experienced operators looking to enhance their antenna systems.

Low noise, receive only coax loop antennas for 160 - 10 meters HF bands

Constructing a 2-meter 5/4 wave antenna, N1HFX details a design fully enclosed within 3/4-inch PVC tubing, addressing the significant velocity factor of PVC which necessitates a 19% reduction in physical length. The design incorporates a specific matching system using 300-ohm TV twin lead to counteract the highly inductive impedance component inherent in a 5/4 wave radiator. Key components include #18 stranded insulated wire for the radiating element, RG58/U coax, a PL259 connector, and a hardwood dowel for internal support, all carefully dimensioned for optimal performance within the PVC housing. The article provides precise cutting lengths for the twin lead and #18 wire, with the overall assembly measuring 77 3/4 inches, reflecting an approximate velocity factor of 0.81. Tuning instructions emphasize taking SWR readings with the antenna assembly inside the PVC, adjusting the #18 wire and twin lead in small increments to achieve a low SWR across the 2-meter band. The prototype antenna achieved SWR readings below 1.2:1 across the entire band, and N1HFX suggests an estimated 6 dB gain when properly mounted, offering a cost-effective alternative to commercial antennas.

The HB9ABX RoomCap antenna document details the construction and performance characteristics of a compact HF antenna design. It presents a series of comparative field tests conducted between July and September 2005, evaluating the HB9ABX antenna against established designs like the Microvert MV-500, Cushcraft R5/R7000 verticals, and a 5-element DJ2UT Yagi beam. Specific test scenarios include mobile installations, rooftop deployments, and comparisons on 20m, 40m, 80m, and 160m bands, with signal reports from various European and DX stations. The resource emphasizes the antenna's small physical footprint and its claimed efficiency across multiple HF bands. Test results consistently show the HB9ABX antenna performing comparably to, and often outperforming, larger reference antennas in terms of received signal strength, with reported differences of 1 to 2 S-points (6-12 dB) in many contacts. Notably, a 20m DX test on July 26, 2005, indicated the 1.3m HB9ABX radiator yielded 2-3 S-points stronger signals than an R7000 vertical for US DX stations. An August 12, 2005, test on 40m highlighted the HB9ABX's superior signal-to-noise ratio in urban QRM, demonstrating 10-18 dB better performance than an R7000. The document includes specific callsigns, signal reports, and QTHs for each comparison, providing empirical data for the antenna's performance claims.

Small HF balcony antenna project

Demonstrates adapting the _Moxon rectangle_ antenna design for 2-meter VHF operation, highlighting its unique characteristics for specific applications. It details how the antenna's small size and distinctive far-field pattern, typically associated with HF, can be effectively utilized on VHF. The resource provides modeled dimensions for three different element diameters (1/4", 1/2", 1") and discusses the necessary adjustments to maintain optimal performance, such as gap spacing and element lengths, to achieve a 50-Ohm feedpoint impedance. The article presents predicted performance data, including gain (dBi), front-to-back ratio (dB), and feedpoint impedance (R, jX) across 144, 146, and 148 MHz. It analyzes free-space azimuth patterns and discusses the antenna's behavior when horizontally and vertically polarized over ground, including its suitability for fixed installations, repeater applications, and even satellite communications. Construction considerations, such as bending elements and maintaining critical gap distances, are also addressed. Furthermore, the content explores advanced configurations like using two back-to-back rectangles for broader coverage and a crossed-Moxon setup for circular polarization, suggesting potential for urban communication and satellite work. The author, _L. B. Cebik, W4RNL_, emphasizes the Moxon's strengths in broad bandwidth, wide beamwidth, and high front-to-back ratio, rather than maximum gain.

The FT-817 is a small 5W MF/HF/VHF/UHF transceiver with internal batteries. Here is an assortment of technical information K6XX put together about this rig that might interest you.

The directory lists several files, including `_template1.html` and `_template2.html`, last modified in 2006 and 2004 respectively, indicating a historical web project. Key scripts like `hfcc_cfm.pl` and `index.cgi`, updated in 2011, suggest a **CGI-based application** for searching shortwave broadcast schedules. The presence of `_template1.tpl` and `_template2.tpl`, both modified in 2015, points to a templating system for dynamic content generation. The file `hfcc_create-fill_mys..>` (likely `hfcc_create-fill_mysql.pl`) implies interaction with a database, possibly MySQL, for storing and retrieving **HFCC (High Frequency Co-ordination Conference)** schedule data. The `lang.cgi` script, last updated in 2002, suggests early support for multilingual interfaces or language-specific content delivery. The `q.txt` file, a small 804-byte text file, could be a query log or a simple data file. The overall structure indicates a system designed to process and present shortwave broadcast information, likely by querying a database of scheduled transmissions on various HF frequencies. The file modification dates suggest the project was actively developed and maintained over a period spanning more than a decade, with core components last updated around 2011 and templates in 2015.

Presents a crystal-controlled CW transmitter design for the 40-meter band, delivering 5 to 7.5 watts output power. The circuit innovatively employs an _IRF510_ power MOSFET in the final amplifier stage, diverging from conventional bipolar transistors. This design offers high gain, nearly 90% efficiency, and robust resistance to high SWR, allowing 30-second key-down operation into an open circuit without damage. A critical aspect is the precise adjustment of the MOSFET gate bias via a 10K trimmer pot, _R10_, to maintain quiescent current between 5 and 10 mA, preventing thermal runaway inherent to bipolar devices. The prototype was constructed on a _Radio Shack universal board_ and achieved immediate operational success. The design requires a 15-volt Zener diode to protect the MOSFET gate from overvoltage. Component sourcing information is provided, including specific crystal frequencies (7.040 MHz or 7.122 MHz) available from _Dan’s Small Parts & Kits_ or Doug Hendricks. The fixed frequency can be slightly adjusted with a trimmer capacitor. A complete bill of materials, including resistor values, capacitor types, toroid specifications, and transistor part numbers, is detailed, alongside a clear schematic diagram.

2m SSB/CW-12.5 Ohm Yagis with extrem high gain and small bandwidth. These Yagis were constructed as ultra-light, portable Yagis with extrem high gain. They have small bandwidth and are working from 144,0-144,8MHz with good SWR.

The Inverted L antenna is a versatile and efficient design suitable for small gardens, allowing amateur radio operators to operate on multiple bands. This project outlines the construction of a 5-band inverted L antenna, which can cover HF bands effectively. The design is particularly advantageous for those with limited space, as it requires minimal ground space while providing good performance. The antenna can be easily constructed using common materials, making it accessible for both beginners and experienced hams. In this guide, GM0ONX shares detailed instructions on how to build the inverted L antenna, including dimensions and tuning tips. The project emphasizes the importance of proper installation and grounding to ensure optimal performance. Additionally, it discusses the antenna's compatibility with various transceivers and the potential for portable operation. This resource is ideal for hams looking to enhance their station with a multiband antenna that performs well in limited space.

A multiband stealth antenna. Tuner is required. The antenna is made from a $15, 500 ft roll of black #14 insulated stranded wire, about 120 small black wire ties, and maybe 30 or so large black wire ties.

Isotron antennas are low-profile HF antennas. If you need a small antenna, then an Isotron may be the answer. Bilal isotron antennas.

Constructing a **2-meter** J-pole antenna from readily available copper plumbing components offers a robust and cost-effective solution for VHF operation. This design, dubbed the "Plumber's Delight," functions essentially as a half-wave dipole fed by 50-ohm coax via a **gamma match**. It incorporates a quarter-wave copper tubing support, which, when affixed to a metal mast or tower, enhances forward power in the direction of the radiating elements. The original configuration utilized a small ceramic trimmer capacitor for the gamma match, suitable for up to 10 watts. A subsequent modification replaced this with a 50 pF variable capacitor housed in a plastic enclosure, accommodating higher RF power and improving weather resistance. The antenna elements are secured using a copper "T" fitting, and an SO-239 connector mounts directly to this fitting. Performance includes gain away from the support mast, and tuning is straightforward by adjusting the gamma match capacitor for a 1:1 SWR. The total cost for materials, excluding the capacitor and coax, can be under $10.

Simple, inexpensive and easy to erect, this antenna provides directivity, low angle radiation and a small gain on a number of HF bands.

A 5-band (20m-10m) HF antenna - Just 7ft square and great for a small garden. Build it yourself for around 60 GBP.

Constructing a compact UHF Moxon antenna for portable radio or TV applications demands a small, easily transportable aerial. This project focuses on a straightforward build method rather than a specific frequency design, leveraging _MoxGen_ software by AC6LA to derive precise dimensions. The author's approach utilizes an epoxy printed circuit board as the support, with traces drawn by a special felt-tip pen for soldering the antenna elements after an etching bath. For high-frequency work, particularly in the GHz range, the choice of insulating material is critical; the article emphasizes the necessity of quality UHF or SHF-grade insulation. A standard SMA connector is integrated, with one element making electrical contact via the nut and the other soldered to the central pin. This ensures a robust feedpoint for the coaxial cable. The coaxial cable, fitted with its connector, is threaded through a 12mm PVC tube that functions as a mini-mast. This tube also defines the antenna's forward direction, which should be aimed at the target signal. A sanitary clamp at the base of the tube secures it to a photographic tripod via its 7mm thread, providing a stable and portable mounting solution.

A base station antenna you can easily build for 146,220 or 440 MHz, with performance similar to a J-pole but smaller and less obstrusive

The ARRL page, titled "The HF Mobile Antenna," serves as a curated index to various _QST_ articles focusing on constructing mobile HF antennas. It presents several projects for the mechanically inclined amateur, suggesting that homebrewed antennas can achieve efficiency comparable to commercial versions. For instance, one entry details a **five-band** antenna for RVs, utilizing a fold-over Hustler 4BTV, while another describes a "Bug Catcher" design for 80 through 10 meters. Further projects include a budget-friendly $20 HF mobile antenna made from PVC and wire, covering 20 through 6 meters, and the "Alpha Special," a multiband horizontal antenna originally for 1960s station wagons, now suggested for mini-vans. The resource also addresses antenna mounting solutions specifically for travel trailers and campers, providing practical insights for those operating from recreational vehicles. Rounding out the collection are the "Connecticut Longhorn," a 75-meter horizontal whip with remote tuning, and its redesign, the "Connecticut Shorthorn," adapted for smaller vehicles post-1970s. This compilation offers a historical perspective on mobile antenna innovation and practical construction guides for various HF bands and vehicle types.

JJ0DRC's HF multi-band delta loop antenna project, initially conceived during the waning peak of Cycle 23, addresses the common challenge of achieving effective DX operation from a small residential lot in Japan. Dissatisfied with a ground plane antenna's performance in SSB pile-ups, the author sought a beam-like solution without a tower, drawing inspiration from a JJ1VKL article in CQ Ham Radio Sep. 2000. The antenna, constructed in October 2000, employs two 7.2-meter fishing rods (37% carbon fiber, reinforced with cyano-acrylate glue and aluminum tape) and 1mm enameled wire, fed by an Icom AH-4 external antenna tuner. While the exact beam pattern remains unmeasured, JJ0DRC observed a significantly higher callback rate compared to dipole antennas, particularly on higher bands. The system's circumference length of 15-20m is crucial for maintaining a good beam pattern across HF bands, though performance on lower bands like 80m, 40m, and 30m becomes less directional as the length deviates from a full wavelength. Ongoing maintenance addressed degradation issues, including aluminum tape cracking and wire breakage at connection points due to strong winds (often exceeding 10-15m/s in winter). The author reinforced rod connections with IRECTOR PIPE SYSTEM components and INSU-ROCK ties, and improved wire attachment methods using Cremona rope and epoxy bond to enhance durability.

Illustrates the construction of a compact _Moxon_ beam antenna specifically tailored for the 40-meter band (7 MHz). The resource details a homebrew project by W7XA, emphasizing its design for limited space while maintaining good bandwidth and directivity characteristics. It highlights the practical application of the _Moxon_ rectangle model to achieve performance on a lower HF band. The primary content is a downloadable PDF document titled "40-Meter-Mini-MOXON-Beam-Antenna.pdf," which provides comprehensive illustrations and technical specifications for replicating the antenna. This includes dimensions, materials, and assembly instructions, making it a practical guide for radio amateurs interested in directional antennas for HF. The project demonstrates how a relatively small footprint can yield a directional antenna suitable for DXing or contesting on 40 meters, a band typically requiring much larger arrays for similar gain and front-to-back ratios. The documentation supports hands-on construction.

The Q-signal **QRP** signifies a request to reduce power, and in amateur radio, it defines operating with 5 watts or less for CW and 10 watts or less for SSB. This article addresses common inquiries from new hams regarding the practice, its benefits, and implementation methods. It explains how a 5-watt QRP signal, compared to a 100-watt signal, typically results in only a 13dB drop in signal strength, equating to about two S-units, still providing solid copy under most conditions. Hams choose QRP for various reasons, including seeking a greater challenge in DXing or contesting, reducing band interference, or enabling portable field operations with lightweight, battery-efficient equipment. A modern single-band CW transceiver, key, and antenna can fit into a pocket, offering receiver performance comparable to commercial rigs and extended operation on a small battery. This portability facilitates operations in remote locations where higher-power setups are impractical. Operating QRP can involve simply reducing power on an existing commercial HF rig or building a dedicated QRP transceiver from a kit, such as the **Wilderness Radio SST** with its 2-watt output and 15mA receive current draw. While SSB is viable, CW remains the most popular and efficient mode for QRP due to its superior signal-to-noise ratio. The article lists common QRP calling frequencies across 160m through 10m bands for both CW and SSB, and highlights organizations like QRP ARCI and NorCal that support the QRP community.

A well documented article on a small magnetic loop antenna for the 40 meters band

Presents the Light Loop, a small magnetic loop antenna optimized for 40m through 10m operation, demonstrating its construction for portable QRP use. The design emphasizes lightweight materials and a compact form factor, making it suitable for handheld or backpack deployment during field activities. It details the primary radiating element, the coupling loop, and the variable capacitor required for resonance across the specified HF bands. The article provides specific component choices, such as the 1.5-inch diameter aluminum tubing for the main loop and the 10-365 pF variable capacitor for tuning. It discusses the importance of precise loop circumference and spacing for efficient impedance matching and bandwidth characteristics. The resource includes practical advice on achieving resonance and optimizing performance for low-power transceivers. Construction notes cover the mechanical assembly, including mounting the capacitor and feedpoint connections. It highlights the antenna's suitability for pedestrian mobile operations, offering a practical solution for HF communication without extensive setup. The design aims for a balance between portability and effective radiation on the lower HF bands.

Multiband no trap no gap antenna. This Antenna is a small wonder, easy to build and allow you to work all HF spectrum with your TRX and it's internal ATU.

A small portable antenna tuner for HF and VHF bands by ON6MU

Based on DL6UW Yagi antenna's design-formula The forward gain is 13.6 dBi (about 11.5 dBd) and it's pretty small, about 1,5 m in length

Constructing a high-gain, compact antenna for 2 meters often involves balancing theoretical performance with practical build challenges. WB8AHT recounts his journey in building a 6-element _Super Duper Moxon_ antenna for 144 MHz, inspired by designs from M0PXS and GW3YDX. He initially encountered discrepancies in published dimensions for the _HAARP Antenna_ and the _Super Moxon_, leading to on-air SWR issues and suboptimal performance. His methodical approach involved cross-referencing, direct communication with Phil Simpson (M0PXS), and iterative adjustments to element lengths based on observed results and a _SARK-110 Antenna Analyzer_ scan. After modifying the reflector/driven element and third director dimensions, the antenna achieved a respectable 1.35:1 SWR at 144.200 MHz. Field testing with 50 watts yielded contacts up to 500 miles, suggesting performance close to the 15 dBi gain predicted by _4NEC2_ software, despite its compact 40-inch boom. The article includes specific construction notes, such as tubing sizes (1/2-inch and 3/8-inch aluminum) and feedpoint spacing (50mm). The author's experience highlights the importance of real-world validation for antenna designs, even those with strong theoretical backing. He provides a table of tubing lengths for 6m, 4m, and 2m versions, along with his final, optimized dimensions, offering a practical blueprint for fellow hams interested in replicating or further experimenting with this high-performance, small-footprint VHF antenna.

Loop antennae have been used from ELF to UHF since the beginning of radiocommunications. At low frequencies, the main problem for loop antennae is to have enough sensitivity; the antenna being very small respect to the wavelength the collected energy is also small. To increase the output level the loop may be made resonant, so loosing it%u2019s intrinsic aperiodic characteristics.

For radio amateurs seeking compact and efficient antenna solutions, particularly for restricted spaces or noise reduction, HF loop antennas present a viable option. This resource compiles several articles from the ARRL, detailing the theory, design considerations, and practical construction of various loop configurations. Topics include small transmitting loops, receiving loops, and multi-band designs, often emphasizing their performance characteristics such as directivity, bandwidth, and impedance matching. The collected articles provide insights into the comparative performance of different loop geometries, such as circular versus square loops, and discuss the impact of conductor size and tuning methods on efficiency. Practical applications are explored, including their use in portable operations, stealth installations, and urban environments where noise mitigation is critical. The content often includes construction diagrams, parts lists, and performance data derived from modeling or field tests, enabling hams to replicate or adapt the designs for their specific operating conditions.

Small and inexpensive homebrew HF radio 5W Output, CW SSB AM FM, DSP, Speech Processor, Sprectrum Scope, Watefall Display. mcHF is a small, home-brewed amateur radio project. Firmware is released as open source.

Experiments on HF antennas for restricted spaces. In this article author experiments antennas for 80-10 meters band having just a very small garden and several restrictions. Basic antennas consists of laded multiband dipoles and fan dipole antennas

Article about small magnetic loop antennas with notes on realization of magnetic loops for several HF bands and the six meter band

Constructing a compact, single-feed triband Moxon antenna for 20, 15, and 10 meters is detailed by DU1RZ, drawing from his personal experience with space-constrained antenna projects. Initially fascinated by cubical quads, the author transitioned to Moxon designs in 2005 after realizing his roof space was insufficient for a bulky quad. His first experimental monoband Moxon for 15 meters, built from repurposed materials, provided solid DX QSOs for seven years, despite being slightly below the 21 MHz band center. The project outlines the design process, including using the _MOXGEN Calculator_ for element dimensions and material selection, such as #14 AWG enamel copper wire and fishing poles for spreaders. DU1RZ shares insights from simulations with DL2GMS regarding insulated versus non-insulated wire performance, noting that insulated wire can shift resonant frequencies lower. The assembly instructions cover preparing wire elements, connecting feed points, and tuning the antenna, with initial SWR measurements taken at 10 feet and final readings on a mast showing excellent results: 1.0:1 on 14.225 MHz, 1.1:1 on 21.250 MHz, and 1.3:1 on 28.50 MHz. Transmission tests with 4F1BYN indicated a front-to-back ratio of approximately 2 S units with 10 watts output. The author emphasizes adaptability, encouraging builders to use readily available materials rather than strictly replicating his setup. Key observations from DU1RZ and DL2GMS highlight the antenna's strong performance across 20, 15, and 10 meters, good front-to-back ratio, full bandwidth on 20 and 15 meters, and its small turning radius of about 4.18 meters (13.54 feet), making it suitable for limited antenna space. Its lightweight construction and low wind load are also noted as significant advantages.

This resource details the construction of a portable antenna tripod designed for supporting small vertical antennas, utilizing readily available electrical metal tubing (EMT) or conduit. It outlines the necessary components, including a custom-fabricated _EARC tripod plate_, standard hardware, and a 10-foot section of 1/2-inch EMT cut into specific lengths for legs and a center support. The instructions cover assembly of the tripod plate, leg construction, and integration with a fiberglass fishing pole like the _Kwik Stix_ or _Shakespeare Wonderpole_ to support a vertical wire HF antenna. The project also describes an adaptation for using the tripod with 3/8x24 threaded mobile antennas such as _Hamsticks_ or _Buddisticks_, where the tripod structure itself contributes to the antenna's counterpoise system. A complete parts list is provided, along with ordering information for the specialized EARC tripod plate, which serves as a fundraiser for the Honolulu Emergency Amateur Radio Club. The document includes photos illustrating the assembled tripod and its use with a fiberglass pole.

Receive-only loop antennas have some nice response characteristics that make them ideal when used for reception of skywave signals.

Compiles a detailed calendar of RTTY contests, providing essential information for digital mode enthusiasts. It lists contest dates, links to official rules, and often includes historical results and records, enabling operators to plan their contesting schedule and review past performances. The resource covers a wide array of RTTY events, from major international contests like the _ARRL RTTY Roundup_ and _CQ WW RTTY_ to smaller, regional competitions. Operators can quickly identify upcoming RTTY contests, review specific rules for each event, and access historical data to gauge competition levels. For example, the site details the _BARTG RTTY Sprint_ and the _SARTG New Years_ contest, offering a centralized hub for RTTY contesting information. This resource is particularly useful for those aiming to improve their digital contesting skills or track their progress against established **records**.

Hams have been putting stations in their cars since the Twenties. Today, there is great satisfaction in facing the challenge of installing a transceiver in our small cars and pick-ups, using somewhat inefficient antennas

HFRadio.US is a woman-owned small business that specializes in products for the HF market. We have our own line of broadband HF antennas plus other specialized products primarily for the Motorola Micom series radios.

This project describes the construction of a real CW QRP keyer with a small microcontrolle

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

A multi band antenna for HF band capable to operate from 10 to 80 meters band depending on wire lenght loaded with a small inductance neat the feed end.

Makers of the worlds smallest automatic solid state HF amplifier Expert 1K-FA, Expert 2K-FA and Expert 1.3K-FA

An experimental antenna for HF reception. It consists of a single loop element mounted on the ground. It is stealthy, small, and quiet. EZ-NEC plots and on-air test results are included.

A home made magnetic loop for HF Bands. This small and compact loop is designed to support small power transmissions on HF bands, from 7 MHz to 21 MHz

This is a project aboout compact and portable a QRP antenna tuner for use in the HF ham radio bands from 3-30 MHz, even if it's a compact and efficient project this small antenna tuner will not match any possible load.

Amateur Packet Reporting System (APRS) operations often require compact, reliable solutions for transmitting position data, particularly for mobile or portable stations. This resource details the construction of the _Tiny Track-I_, a transmit-only APRS tracker designed for straightforward integration with a VHF radio and a Global Positioning System (GPS) receiver. It enables hams to broadcast their location without the complexity of a full-duplex TNC. The project outlines the printed circuit board (PCB) layout and schematic, based on an original design by N6BG, with a personal PCB drawing by SV1BSX. It includes specific component placement and notes an additional 10uF/10V capacitor (C5) for improved IC voltage decoupling, a modification not present in the original N6BG diagram. The unit connects to a computer or GPS via a DB9 female connector. This tracker is ideal for basic position reporting, offering a simple and effective way to participate in APRS networks. Its small footprint makes it suitable for vehicle installations or field deployments where space is limited, providing a **reliable 9600 baud** data stream for location updates.

A small, easy to build, copper tube magnetic loop antenna for the 2 meters band. In Italian

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.

Four or Five turn one meter loop antenna for 80 and 160 meter band. This home made receive only antena can be assembled in a small place.