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This is a group for discussing Yaesu's great VX-7R handheld amateur radio.

End-Fed Half-Wave Antennas (EFHWAs) are analyzed for their utility in portable QRP operations, emphasizing their simplicity, efficiency, and predictable radiation patterns compared to other portable antenna types. The discussion contrasts EFHWAs with vertical antennas, random length wires, and center-fed dipoles, highlighting the common pitfalls of each, such as ground system dependency for verticals and feedline issues for dipoles. The article details the electrical half-wavelength calculation using the formula L (Ft) = 468/F(MHz) and explains how EFHWAs can be resonant on harmonic frequencies, enabling multiband operation. Various deployment configurations are presented, including the inverted L, inverted Vee, sloping wire, and vertical setups, each with specific advantages for radiation angle and polarization. For instance, a vertical EFHWA offers a low angle of radiation suitable for DX contacts without requiring an extensive ground system. The resource also addresses the counterpoise requirements, suggesting a quarter-wavelength wire or connection to a metallic structure for decoupling. A schematic diagram for a simple parallel-tuned circuit tuner, based on the _Rainbow Bridge/Tuner_ design, is provided, detailing component values for 30 and 40 meters, including a 6 microhenry toroidal inductor and a 20-100 picofarad mica compression capacitor. The tuner's adjustment process for SWR matching is also outlined.

Calculate dimension for discone antennas online

This PDF document, authored by KT4QW in October 2004, details the construction and modeling of a dual-band, horizontally polarized hanging rectangular loop antenna for **10 and 17 meters**. The design, adapted from *The ARRL Handbook*, utilizes _NEC4WIN95_ software for scaling and optimization, targeting a 50 ohm feedpoint impedance. The resource includes a bill of materials, step-by-step construction instructions, and a discussion of the antenna's radiation characteristics. It presents NEC-generated elevation and azimuth patterns, comparing the loop's performance to a half-wave horizontal dipole at the same height and frequency. The 17-meter element is centered at 18.140 MHz for low SWR across the phone band, while the 10-meter element is centered at 28.500 MHz. Construction involves 14-gauge stranded copper wire and Schedule 40 PVC spreaders, with the total wire length calculated by the formula: Length in feet = 1005/MHz. The feedpoint impedance can be adjusted by modifying the rectangular aspect ratio. The document specifies hoisting the antenna to at least a half-wave above ground for testing. It notes that a balun was tested and found to have no measurable effect on SWR or radiation characteristics. A 2-meter scale model is presented to illustrate the physical design, and a "rotator" string is incorporated for directional adjustment up to 90 degrees.

A group for discussion of the Yaesu FT-857 and FT-857D radios.

Discuss here about hex-beam antennas

Features and specifications for discontinued yaesu ft-100d radio

The document discusses a two-element parasitic Delta-Loop array for the 40 meters band, aimed at radio amateurs interested in antenna projects. It provides detailed plans and instructions for building a homemade Delta-Loop antenna.

Explains the Federal Communications Commission (FCC) vanity call sign program, outlining the specific rules and procedures for amateur radio operators in the United States to obtain a personalized call sign. It details the eligibility requirements based on license class, the application process using FCC Form 605, and the various group formats (e.g., _1x2_, _2x1_, _2x2_) available to different license classes, such as Extra and Advanced. The resource clarifies the priority system for vanity call sign requests, including previous holders and close relatives, and discusses the typical processing times for applications. It also provides insights into how the FCC assigns available call signs and offers practical advice for increasing the likelihood of securing a desired call, referencing the _ARRL Letter_ for updates.

The K8ZT website provides a curated collection of amateur radio resources, encompassing software tools, informational articles, and external links relevant to various aspects of the hobby. It features utilities for _log analysis_, insights into QRP operations, and guidance on obtaining vanity callsigns. The site also includes sections dedicated to shack design principles and general ham radio information, reflecting a broad interest in practical station setup and operational enhancements. Specific software offerings are presented alongside discussions on their application, such as tools for analyzing contest logs to identify operational efficiencies or areas for improvement. The content often integrates personal experience with technical explanations, providing a practical perspective on topics like antenna selection for low-power operations or optimizing station workflow. The resource distinguishes itself by combining software recommendations with contextual information, aiding operators in making informed decisions about their station's technical and operational aspects.

The document details the optimization and construction of the _Maria Maluca_ antenna, a compact 6-band (20m-6m) directional beam. It presents a comparative analysis of shortwave antenna principles, highlighting the efficiency gains achieved by using an open feeder line and tuner as a resonant unit, contrasting this with the losses associated with traps or capacitive loads in multiband antennas. The resource specifically revisits an older South American 2-element design for 10, 15, and 20 meters, applying modern NEC-based software to develop a six-band version. Performance data is meticulously tabulated, showing impedance, free space gain, gain at 12m height, elevation angle, and front-to-back (F/B) ratio for each band from 20m through 6m. For instance, on 15m, the antenna achieves 5.1 dBd free space gain and 13.72 dB F/B ratio. The construction section provides practical guidance on element assembly using aluminum pipes and hose clamps, detailing the use of a heavy-duty glass fiber reinforced polyamide rod for electrical separation and bending strength. It also specifies the use of 450-ohm _Wireman_ line CQ 552 for the transmission line. The document includes diagrams for rod fixing, an air-wound balun, and a vertical elevation diagram for the 15m band, illustrating its DX qualification. It also discusses the antenna's suitability for portable and expedition operations, noting its compact transport dimensions (max 1.50m length, 12 lb weight) and quick assembly time (under 15 minutes). The author, Dipl.Ing. Helmut Oeller, DC6NY, is identified as a source for material kits.

The article "Exploring the World of 10 Meter Beacons" by Ken Reitz, KS4ZR, provides an in-depth look at 10-meter beacon operations, focusing on their utility for propagation analysis. It details FCC Rules part 97.203 governing beacon stations, including license requirements, power limits (under 100 watts), and the specified band segment of 28.200-28.300 MHz for U.S. operations. The content highlights the diversity in beacon construction, from converted CB radios to home-brew QRP transmitters, and discusses the robust operating conditions these 24/7 stations endure. The resource presents several case studies of active 10-meter beacon operators like Ron Anderson KA0PSE/B, Domenic Bianco KC9GNK/B, and Bill Hays WJ5O/B, detailing their equipment, antenna setups, and typical signal report volumes. It also introduces the NCDXF/IARU International Beacon Project, which features 18 synchronized beacons worldwide transmitting on 28.200 MHz at varying power levels (100W, 10W, 1W, 100mW) to facilitate propagation testing. The article also covers the PropNet Project utilizing PSK31 on 28.131 MHz and the 250 Synchronized Propagation Beacon Project on 28.250 MHz. Practical advice for monitoring includes using the RST reporting method, understanding the impact of the solar cycle on 10-meter propagation, and tips for setting up a personal beacon, such as frequency selection and power output considerations. The IY4M Guglielmo Marconi Memorial Beacon Robot on 28.195 MHz is also mentioned for its automatic QSO mode. The article concludes with a list of other resources for 10-meter beacon information.

A quarter-wave vertical antenna design for HF operation offers a practical solution for radio amateurs seeking a compact and efficient multi-band radiator. This project details the construction of a 5-band HF vertical, drawing inspiration from established commercial products such as the _DX COMMANDER_ and the MV6. The design emphasizes ease of assembly and disassembly, making it suitable for portable operations or installations with limited space. The article provides insights into various construction methods and offers practical tips for building a robust yet lightweight antenna. It highlights the benefits of a vertical configuration for DX contacts, particularly on the lower HF bands, and discusses real-world performance observations. The antenna is designed to cover multiple HF bands, providing versatility for various operating scenarios. Operators can achieve significant DX results with this type of antenna, often comparable to more complex arrays, especially when deployed with an effective ground system. The project aims to empower hams to build a capable antenna without significant financial outlay.

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

The Discovery series of amplifiers are designed and built in the UK by Linear Amp UK Ltd, one of the world's leading amplifier manufacturers, specializing in high power RF tube amplifiers. The amplifiers use large GS31 or GS35 ceramic triode tubes. Band coverage 6m, 2m and 70 cms

Presents the design and construction of the OK2FJ Bigatas, a portable, automatically tuned vertical antenna covering 80 through 10 meters. It details two distinct control systems: one utilizing BCD band data from Yaesu FT-857/897 transceivers, and another employing voltage level sensing for the Yaesu FT-817. The resource provides specific instructions for building the antenna's radiating element, loading coil with switchable taps, and the control circuitry, emphasizing the use of readily available components. The article outlines the physical construction of the antenna, including the use of duralumin tubes for the radiator and a PVC tube for the coil form. It specifies coil winding details, tap points, and the integration of radial wires for ground plane operation. The control electronics section provides schematics and component lists for both the BCD decoder (using a 74LS42 IC) and the voltage comparator (using an _LM3914_ bargraph driver), enabling rapid, automatic band switching without the minute-long tuning delays common in other systems. Crucially, the antenna achieves rapid band changes, with typical SWR values centered on common operating segments, such as **3.7 MHz** for 80m SSB. It also discusses modifications for CW operation on 80m and the trade-offs between antenna efficiency and full-range automatic tuning on higher HF bands, where manual adjustment of radiator length is suggested for optimal performance on 15m, 12m, and 10m. The resource includes construction photos and a discussion of cable requirements for reliable operation.

This resource details the computer-optimized design of the _ZS6BKW_ multiband dipole, an evolution of the classic _G5RV_ antenna. It begins by referencing the original 1958 RSGB Bulletin article by Louis Varney G5RV, explaining the operational principles of the G5RV's flat-top and open-wire feedline on 20m and 40m, noting its impedance transformation characteristics for valve amplifiers of that era. The article then transitions to the rationale for optimizing the design for contemporary solid-state transceivers requiring a 50 Ohm match. The core of the project involves using computer modeling to determine optimal lengths for the flat-top and matching section, aiming for a VSWR of less than 2:1 on multiple HF bands. It discusses the process of calculating feedpoint impedance based on antenna length and frequency, referencing professional literature from Professor R.W.P. King at Harvard University. The analysis also considers the characteristic impedance (Z(O)) of the open-wire line, identifying a broad peak of adequate values between 275 and 400 Ohms. Specific design parameters for the improved ZS6BKW are presented, including a shorter flat-top and a longer matching section compared to the original G5RV, with a velocity factor of 0.85 for the 300 Ohm tape. The article confirms acceptable matches on 7, 14, 18, 24, and 28 MHz bands when erected horizontally at 13m, and also discusses performance in an inverted-V configuration, noting frequency shifts. The author, Brian Austin ZS6BKW, emphasizes the antenna's suitability for modern 50 Ohm coaxial cable without a balun.

The ICOM IC-7300 is a cutting-edge HF transceiver that has garnered significant attention since its release. This review, published by ARRL in QST, provides an in-depth analysis of its features, performance, and usability. The IC-7300 is known for its direct sampling technology, which enhances its sensitivity and selectivity, making it a favorite among amateur radio operators. The review covers various aspects, including the user interface, audio quality, and overall operational capabilities, providing valuable insights for both new and experienced hams. In addition to its technical specifications, the review discusses the IC-7300's performance in real-world scenarios, such as DXing and contesting. It highlights the transceiver's ability to handle weak signals and its versatility across different modes. The review serves as a helpful guide for those considering the IC-7300 for their station, offering a balanced perspective on its strengths and potential drawbacks. Overall, this review is an essential resource for anyone interested in the ICOM IC-7300 and its place in the amateur radio landscape.

Amateur Television (ATV) operations, particularly within the Arizona region, require dedicated resources for technical information, operational guidance, and community engagement. This club provides a focal point for hams interested in transmitting and receiving video signals on amateur bands. Members engage in local ATV repeaters, participate in technical discussions, and share knowledge on video modulation schemes, antenna designs, and station configurations. The club supports activities ranging from local simplex contacts to wider area repeater usage, fostering skill development in this specialized mode. The organization maintains a roster of club officers and offers membership opportunities to local amateurs. It also curates offsite links to other ATV resources, expanding the knowledge base available to its members and the broader amateur community. The club's emphasis on ATV helps propagate interest and technical expertise in a mode that combines traditional RF engineering with video technology.

Page on amplification topics. From vacuum tubes to various components, discussion on stability and arcin causes.

Home made discone antenna used with RTLSDR dongle

The U.S. Amateur Radio Callsign Lookup service, hosted by the University of Arkansas at Little Rock (UALR), offers a direct interface for querying the FCC's amateur radio license database. This resource is specifically designed for rapid retrieval of licensee information, including callsign, name, address, license class, and expiration date, all critical data points for QSLing and contact verification. The underlying database is refreshed daily, ensuring that the presented information reflects the most current FCC licensing records available. This service distinguishes itself by its direct reliance on official FCC data, processed and maintained by a university institution, which lends a degree of authoritative accuracy to its lookups. Users can input a specific callsign to instantly access detailed license particulars, facilitating efficient station identification and record-keeping for DXers and contesters alike. The daily update cycle minimizes discrepancies often found in less frequently synchronized callbook services. The UALR callsign lookup functions as a straightforward, no-frills utility, prioritizing data integrity and accessibility for the amateur radio community. Its operational simplicity and consistent data refresh schedule make it a reliable reference for verifying U.S. amateur radio licenses.

A comprehensive collection of DX information consisting of news, audio files, station profiles, equipment articles, discussion forum, DXpedition reports and logs for mediumwave, shortwave and FM DXers.

Demonstrates the construction of two distinct wideband RF preamplifiers, detailing their component requirements and performance characteristics. The first design leverages monolithic microwave integrated circuits (MMICs) such as the MAR-6, MAR-8, or PGA103, offering a broad frequency response from DC to 2 GHz with a gain of 22.5 dB at 100 MHz and a noise figure typically below 3 dB. This MMIC-based amplifier incorporates protection against power supply transients and features a 50 Ohm input/output impedance, operating from an 8-20 volt supply with low current drain. The second preamplifier design utilizes a BSX-20 transistor, providing amplification across the 14 MHz to 550 MHz range. This simpler, more economical build achieves an average gain of 12 dB at 145 MHz and a noise figure of approximately 1.1 dB. It operates from a 7-15 volt battery supply with a current draw of 6 mA. Both projects emphasize critical construction techniques, such as maintaining short RF connections, ensuring 50 Ohm impedance paths, and mounting the circuit within a shielded enclosure to optimize performance and minimize noise. The resource also discusses phantom power options for antenna-mounted preamplifiers and precautions for use with transceivers, including output protection diodes and static bleeders.

Coax is a very important part of a satellite station. It is almost as important as the antennas you choose. This article discusses choosing coaxial cables for satellite communication, emphasizing factors like line loss. It compares types such as RG-8, RG-58, Belden 9913/9913F, LMR-400, and hardline, highlighting their impact on signal preservation.

Constructing a functional spectrum analyzer for the 0-100 MHz range presents a significant challenge for radio amateurs, often requiring specialized components and careful calibration. This project details a homebrew spectrum analyzer design utilizing common integrated circuits like the _SA605D_ FM receiver IC and _MAR-6_ MMIC amplifiers, aiming for a cost-effective solution. The design incorporates a low-pass filter, RF amplification, a voltage-controlled oscillator (VCO) for downconversion, and multiple IF stages at 150 MHz and 10.7 MHz, with a resolution bandwidth (RBW) of 15 kHz. Critical components such as the _SBL-1_ mixer and varicap diodes are specified, alongside instructions for winding inductors and tuning filters. The analyzer's performance is discussed in terms of input level limitations, specifically the 1dB-compression point and third-order intercept point, to ensure accurate measurements and prevent component damage. The _SA605D_'s logarithmic Received Signal Strength Indicator (RSSI) output serves as the detector, driving the Y-input of an oscilloscope, while a _TL084_ op-amp generates the sweep signal for the X-input. Potential enhancements include adding a step attenuator, improving front-end filtering, and implementing switchable IF filters for variable RBW, allowing for greater versatility in analyzing RF signals.

The Deutscher Amateur-Radio-Club (DARC) e.V. serves as the largest association for radio amateurs in Germany and Europe, structured into 24 districts and approximately 960 local chapters nationwide. Its core mission involves fostering amateur radio and establishing favorable conditions for the Amateur Radio Service. The DARC actively participates in international affairs as a member of the **International Amateur Radio Union (IARU)**, ensuring German interests are represented on a global scale. Recent activities include the announcement of the FUNK.TAG in Kassel for April 25, 2026, and the HAMCamp at **HAM RADIO** in Friedrichshafen from June 26-28, 2026, offering discounted participation for young operators up to 27 years old. The club also supports special events, such as a short-term award and special callsign DB15ØWG to commemorate the 150th anniversary of the Weimar–Gera railway line, active from April 1 to June 30. Regular updates, like the Deutschland-Rundspruch 11/2026, cover topics from the status of 70 MHz band permissions to satellite deployments like Ten-Koh 2, and contest results such as the WWA YL event. Propagation forecasts, including Kp indices and solar flux values, are provided by Hartmut Büttig, DL1VDL, offering insights into HF conditions and Gray-Line DX opportunities. The DARC also reports on district elections and space-related events like the Bochumer Weltraumtag, highlighting the diverse engagement of its members.

Mailing list for people who own or are interested the various Realistic DX series radios from Radio Shack/Tandy. The DX-160 and DX-302 are frequenty discussed.

This page displays a 404 error, indicating the original content describing a simple _RS232 interface_ circuit is unavailable. The circuit was reportedly designed for older Kenwood transceivers and featured in chapter 22 of the _ARRL Handbook_. It likely involved basic electronic components for level shifting and signal conditioning between a computer's serial port and the radio's control interface. The intended project would have detailed the construction of a hardware interface, enabling CAT control for specific Kenwood models. Such interfaces typically convert TTL or CMOS logic levels from the radio to the +/-12V levels required by RS232, often utilizing ICs like the MAX232 or discrete transistor circuits. While the specific schematics and bill of materials are absent due to the page error, the context suggests a DIY electronics project for enhancing legacy amateur radio station functionality through computer control.

Demonstrates practical solutions for reducing **Radio Frequency Interference (RFI)** in amateur radio operating environments, specifically addressing issues with PC monitors, receivers, and transceivers. The resource compiles advice from experienced operators regarding the selection and application of ferrite cores, including split cores and toroidal cores. It details specific material types like **43, 73, 75, and 77 ferrite**, outlining their effective frequency ranges for RFI suppression, such as 43 material for 30-400 MHz and 77 material for 2-30 MHz. The content provides part numbers for various ferrite products from manufacturers like Fair-Rite Products Corp, distributed by Amidon, and discusses their impedance characteristics across different HF bands. It compares the performance of various ferrite materials at frequencies like 4 MHz, noting that 75 material offers 27 ohms, 73 material 17 ohms, and 43 material just under 10 ohms. Additionally, it touches upon the use of bypass capacitors in conjunction with ferrites to create low-pass filters, emphasizing the importance of identifying common-mode versus differential-mode RFI paths for effective mitigation.

Alfa Tango DX is a premier resource for operators on the 11 meters band, providing a searchable database that includes news, cluster information, and discussion boards. This platform serves as a hub for DXers and contesters, offering valuable insights into activations, dx-peditions, contests, and meetings worldwide. The site features a variety of resources, including event calendars, award programs, and tools for logging contacts. Members can access exclusive content and participate in contests like the AT Women's Day Contest and the Eleven World Wide Contest. With a focus on community engagement, Alfa Tango DX fosters connections among operators and promotes the spirit of amateur radio. Whether you are a seasoned DXer or a newcomer to the 11m band, Alfa Tango DX provides essential information and support for enhancing your amateur radio experience. From QSL services to event participation, this resource is designed to meet the needs of all operators interested in the 11 meters band.

This resource details the conversion of an 80m elevated vertical antenna to include 160m operation, focusing on a relay-switched design over a trap-based approach. It presents specific feedpoint impedance values, such as **32 ohms** for 80m and **14 ohms** for 160m, and discusses the challenges of SWR drift encountered with the prior trap system during RTTY contesting. The article thoroughly explains the design choices for elevated radials, referencing _N6LF QEX data_ to debunk common myths regarding radial length and height, demonstrating that non-resonant radials can offer superior current uniformity. The construction section provides practical insights into building the vertical, including guying strategies, material selection from scrap pipe, and weatherproofing the relay assembly. It highlights the use of a common mode choke for the relay switching line, measuring approximately 5K ohms on both 160m and 80m, and details the L/C matching network's role in achieving a 50-ohm match at the end of a 300-foot RG-11 run. The author describes a precise VNA-based radial trimming procedure, achieving resonant values within a 3 KHz range. The content emphasizes the practical application of theoretical antenna principles, particularly concerning the interaction between the vertical element, cap hats, and the matching network. It offers a candid assessment of component selection, such as using junkbox parts and acknowledging the need for future upgrades to static drain resistors. The article serves as a comprehensive case study for advanced antenna builders tackling multi-band vertical designs.

This group has been created to promote discussion relating to the EH Antenna. There should be many with experience with the EH Antenna, so don't be shy about asking questions on construction and efficiency.

FDLog, a Python-based freeware application, addresses the challenge of synchronized logging for multi-station Field Day operations. It facilitates real-time data sharing across a wireless network, enabling operators to monitor band status and active transmitters at a glance. The software's input system is optimized for minimal keystrokes, streamlining the logging process during intense contest periods. Key features include database synchronization over a wireless network, ensuring all connected computers maintain identical log data. FDLog also incorporates a time synchronization function, designed to keep client programs within a second of a designated master machine, mitigating issues previously encountered with NTP. This internal clock sync can be optionally disabled if not required by the operating setup. Developed initially on Windows 2000, FDLog has demonstrated compatibility with _Linux_ and _macOS_ environments, though some font rendering issues may occur on the latter. The program assists in preparing the ARRL Field Day entry form, simplifying the submission of contest results. User feedback and ARRL rule changes drive ongoing development, with a discussion list available for community support and input.

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.

Discussion on how properly drive and tune athe Ameritron AL-811 power amplifier

The page discusses Axial-Mode Helical Antennas, focusing on turning helical antennas over perfect ground and modeling helices in NEC-2 for optimized design. It covers topics such as high-gain performance, broadband, impedance matching, radiation pattern, feedline, balun, near field, far field, and DIY applications.

Yahoo groups discussing Yaesu FT-950

Examines the historical landscape of "boat anchor" amateur radio equipment manufacturers, focusing on the technical innovations and market dynamics that shaped the industry from the pre-WWII era through the transition to SSB. It details the origins and key product lines of prominent U.S. companies like _Collins Radio Company_, _Central Electronics_, and _Barker & Williamson_, highlighting their contributions to receiver and transmitter design. The resource contrasts early AM technology with the advent of SSB, explaining the circuit changes required in receivers and the complete rethinking needed for transmitters. It discusses the impact of military contracts on company survival and the eventual shift towards smaller, self-contained transceivers. Specific examples, such as the _Collins R-390/URR_ receiver and the _Central Electronics 100V/200V_ broadband transmitters, illustrate the engineering prowess and design philosophies of the era, offering insights into their operational characteristics and enduring appeal among collectors.

Presents the design and performance of a 4-element wire Yagi antenna for the 40-meter band, building upon VE3VN's earlier 3-element switchable wire Yagi. The resource details the antenna's evolution, highlighting the transition from a 3-element to a 4-element configuration and the resulting improvements in gain and front-to-back ratio. It provides specific insights into the antenna's construction and expected operational characteristics. VE3VN shares insights from field results, noting the antenna's performance on 40 meters. The discussion includes the antenna's pattern and matching characteristics, crucial for any DXer or contester looking to optimize their signal on this popular HF band. The author's experience with the previous 3-element design informs the enhancements made to this 4-element iteration. The article includes a visual representation of the antenna's current view, offering a practical perspective on its physical layout. It serves as a valuable reference for hams considering a directional wire antenna for 7 MHz operations, demonstrating a practical approach to achieving enhanced directivity and gain.

The 11-meter band, often associated with Citizens Band (CB) radio, presents unique challenges and opportunities for long-distance communication, particularly for operators interested in DXing. This group facilitates discussions and information exchange among enthusiasts who operate on this frequency, often utilizing single-sideband (SSB) modulation for improved range and signal clarity compared to traditional AM CB operations. The community provides a platform for members to share experiences, technical insights, and propagation reports relevant to 27 MHz operations. Members engage in discussions covering various aspects of 11-meter DX, including antenna configurations, transceiver modifications, and operating techniques to maximize signal propagation across continents. The forum serves as a central hub for coordinating contacts, sharing QSL information, and celebrating successful long-haul QSOs. Specific topics often include optimizing power output, reducing noise, and understanding solar cycle effects on 27 MHz. The group's activities extend to organizing virtual gatherings and promoting ethical operating practices within the 11-meter DX community. It supports both seasoned operators and those new to the band, fostering a collaborative environment for exploring the capabilities of CB radio beyond local communications.

This resource, "Transistor Audio Preamplifier Circuits," offers comprehensive design guidelines for constructing **bipolar transistor** audio preamplifiers. It delves into critical aspects such as quiescent current setting, voltage gain calculation, and the impact of various component choices on circuit performance. The content provides several _schematic diagrams_ illustrating different preamplifier configurations, including single-stage common emitter and two-stage designs, alongside explanations of their operational characteristics and practical implementation considerations. The analysis extends to frequency response, noise performance, and distortion, providing insights into optimizing these parameters for specific audio applications. The resource presents calculated gain figures for various stages, demonstrating how to achieve desired amplification levels. It also discusses the importance of proper power supply decoupling and input/output impedance matching, crucial for integrating these preamplifiers into larger audio systems or ham radio transceivers. The practical application of these designs is evident in their suitability for microphone preamplifiers or general-purpose audio amplification.

Demonstrates the construction and measurement of a single-turn HF receiving loop antenna, built from common materials like electrical conduit and lamp cord. The resource details the physical dimensions, including a 4-meter circumference, and calculates the theoretical inductance at approximately _6.4 uH_. It outlines a method for determining resonant frequencies across the 4-17 MHz range using a _C Jig_ and a _VR-500 receiver_, coupling the loop with a ferrite ring. The article also discusses the impact of receiver coupling on the loop's Q factor, noting a degradation in sharpness due to the transformer's reflected impedance. Analyzes the observed resonant frequency patterns, highlighting an unexpected rise in the loop's effective inductance at higher frequencies, particularly above 13 MHz. While some increase is attributed to distributed capacitance, the rate of rise suggests further investigation. The experimental setup provides practical insights into the challenges of maintaining high Q in simple receiving loops and offers a comparative reference for other homebrew antenna projects, such as those by _VK2TPM_.

The Vee Beam antenna project presents a versatile solution for hams, enabling operation across all eight High Frequency bands (80m to 10m) with significant gain on 20m to 10m. This easy-to-construct antenna utilizes two long wires at an angle, enhancing directional performance and minimizing ground losses. With a low visual profile, it is discreet and effective for various applications. The design allows for optimal leg lengths and included angles, ensuring robust performance while maintaining simplicity in construction and operation. The V Beam antenna is an aerial that you can use on all eight High Frequency amateur bands (80, 40, 30, 20, 17, 15, 12 and 10m) with an antenna tuner, and which gives significant gain on the five bands from 20 to 10 meters band.

A discone antenna plan and pictures with renderings designe mainly for RTLSDR usage

This article presents a technical investigation into spurious emissions from the Yaesu FT-847 transceiver when operating on the 70MHz (4-meter) band. The author discovered significant problems with both factory "UK spec" and modified units. Spectrum analysis revealed that when transmitting at 70.2MHz, the radio produces numerous spurious signals, with the most prominent emission at 45.6MHz measuring only 3dB below the fundamental frequency. The study also documents poor power efficiency on 4m (10.3% at 30W output) compared to 6m operation (23.5% at 30W). Tests verified that jumper configurations had no effect on filter selection. The author warns that using these radios on 4m may violate license conditions due to excessive spurious emissions.

news and views from the UK about the course of CB in the U.K. and Europe.

The document provides a detailed guide on modifying an inverted-L antenna to include the 160 meters band. This enhancement allows amateur radio operators to utilize the lower frequency effectively, which is crucial for long-distance communication, especially during the night. The inverted-L design is popular due to its compact size and ease of installation, making it suitable for various environments. By adding top band capabilities, operators can engage in DXing and contesting on 160m, expanding their operational range and opportunities. The guide includes practical tips and considerations for construction, ensuring that the antenna maintains its performance across the extended frequency range. It discusses the necessary adjustments and materials required for the modification, along with potential challenges and solutions. Whether you are a seasoned operator or a beginner, this project can enhance your station's capabilities, allowing for more versatile operations and improved signal quality on the 160m band.

Frank Donavan, W3LPL , discusses beverages on the CQ-Contest reflector. This is a reprint of Frank's message.

Demonstrates the design principles and performance characteristics of **corner reflector antennas**, emphasizing their high gain and directional properties. It covers critical design factors such as the corner angle and the spacing between the radiating dipole and the reflector vertex. The resource explains how reducing the corner angle increases gain but lowers feed impedance, making matching more challenging. Practical angles of 90 degrees or 60 degrees are discussed, with 90 degrees offering easier impedance matching despite slightly lower gain. Details key design considerations, including reflector side length exceeding two wavelengths and reflector width greater than one wavelength for a half-wave radiator. It specifies reflector construction using wire netting, sheet metal, or parallel metal spines spaced less than 0.1 wavelength. The article provides a table with general dimensions for UHF and VHF bands, noting typical impedance values of 50 to 75 ohms and expected SWR of 1.7:1 on the lower band edge. Adjustable radiator-to-vertex spacing is highlighted as crucial for final tuning.