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This project describes the construction of a W3HH (T2FD) antenna for HF bands (3-30 MHz). While less efficient than a tuned dipole, it offers broad frequency coverage with a maximum SWR of 3.4 and reduces QRM (noise) significantly. On the 80-meter band, it shows slightly weaker signals than a dipole but with improved signal-to-noise ratio. The design includes non-inductive resistors, a 13:1 balun, and a "frog ladder" transmission line. Though not a high-performance antenna, it is compact and versatile, making it ideal for wide-band HF communication. Article in French

From March 2 to March 11, 2018, a Norwegian team operated as Z2LA from Zimbabwe, focusing on 160m through 10m bands using SSB and CW modes. The operation, described as "holiday style," aimed to provide contacts for DXers worldwide seeking a rare DXCC entity. Key equipment included a SUNSDR PRO II, an Elecraft KX3, and an Icom 706 MK2G as a spare radio, supported by two Juma 1000 amplifiers for robust signal output across the bands. Antenna systems were tailored for multi-band operation, featuring an Inv L for 160m and 80m, sloping dipoles for 30m/40m, and a _Hexbeam_ from SP7IDX Technology covering 20m to 10m. For improved reception, the team deployed a SAL 30, two reversible BEV antennas from remoteqth.com, and a BOG from K1FZ, enhancing their ability to hear weak signals. QSL information directs operators to Clublog for log search and M0OXO Charles for OQRS, explicitly requesting no bureau cards. The team comprised LA7THA Rune, LA7WCA Arne, and LA9VPA Thor, successfully making numerous contacts and contributing to the DX community's pursuit of _Zimbabwe_ as a DXCC entity.

This page provides guidance on designing an End-Fed Half-Wave (EFHW) or Random-Length antenna for amateur HF bands, such as 80 or 40 meters. The content explains how to optimize the antenna for multi-band use and match it to a 50-ohm system using an unun. Hams can generate radiation patterns, VSWR charts, and antenna current diagrams for their customized antenna designs. Understanding how antenna dimensions affect performance is essential for successful field operations. The page caters to ham radio operators looking to build efficient and effective HF antennas for their stations.

This article explores the nuanced design challenges of Band Pass Filters (BPF) in radio receivers, balancing low insertion loss, high stop band rejection, and narrow bandwidth. The focus is on the "Series-Trap, Shunt-C" topology, resonator count impact, and meticulous layout design for superior stop band performance across various frequency bands

The Butternut HF2V, originally a two-band vertical antenna for 80m and 40m, was enhanced by the user to include 30m and 20m bands for better digimode DX work during the solar minimum. The additions used components adapted from the HF6V and innovative methods for the 20m addition, either through a parallel vertical element or a lower-mounted independent element, minimizing band interaction. This modified four-band antenna now supports high power across popular HF bands using a single feedpoint.

Learn how to design a Hentenna antenna, a portable asymmetrical double-loop antenna ideal for amateur HF or VHF bands. This page provides details on constructing and optimizing the antenna for maximum performance in DX communications. Discover how altering the antenna's vertical feed section can adjust the VSWR resonant frequency and how changing the support pole's position can alter the beam direction. Originally developed by Japanese 6-meter operators, the 'Hentenna' offers a unique design that allows for horizontal polarization when vertically oriented. Explore radiation patterns, VSWR charts, and antenna currents diagrams to optimize your antenna's performance for long-distance contacts.

The Shrunken Quad antenna is a unique design that offers full-sized performance on the 10m and 15m bands while incorporating linear loading via a trap for operation on the 20m band. This design allows for effective communication in the HF spectrum, making it suitable for both casual operators and serious DXers. The quad configuration provides excellent gain and directivity, which is beneficial for contesting and long-distance contacts. Constructing the Shrunken Quad involves careful attention to dimensions and materials to ensure optimal performance. The antenna's compact nature makes it an excellent choice for limited space situations, allowing operators to enjoy the benefits of a quad without the need for extensive real estate. This project is ideal for amateur radio enthusiasts looking to enhance their station's capabilities with a versatile and efficient antenna system.

This page delves into the debate surrounding the End-Fed Half-Wave (EFHW) antenna, exploring whether it is truly a multiband antenna without the need for a tuner. The author investigates the claims and criticisms surrounding these popular antennas, discussing their resonance on various bands and their efficiency for DXCC achievements. The content is valuable for hams interested in understanding the capabilities of EFHW antennas and their performance across different HF bands, with a focus on practical usage and real-world results.

Robust PACKET, developed by Spezielle Communications Systeme GmbH & Co. KG (SCS), is an OFDM variant of the amateur PACKET mode specifically engineered for HF operation. This mode utilizes a 500 Hz bandwidth with 60 Hz carrier spacing, employing OFDM with 8 DBPSK or DQPSK carriers. It supports 200 bps using BPSK and 600 bps with DQPSK, with each subcarrier operating at a constant rate of 50 Bd. Robust PACKET leverages the AX-25 frame protocol for data transmission, similar to standard PACKET. Compared to traditional PACKET, Robust PACKET demonstrates enhanced resilience against multipath propagation and fading effects, critical for reliable HF communications. It also exhibits a more efficient spectral footprint, with sidebands extending only to 500 Hz, whereas 300 Bd FSK PACKET can produce sidebands up to 730 Hz. Operational frequencies for Robust PACKET include 3.61 MHz, 7.0473 MHz, 10.1473 MHz, and 14.1033 MHz, with specific regional frequencies also documented. Decoding software options for Robust PACKET include Wavecom W-Code and Wavecom W-Spectra. The mode is primarily supported by SCS's 'Tracker / DSP TNC' hardware.

Wavelog, a web-based amateur radio logbook application, launched in February 2024, represents a significant fork from the established Cloudlog platform, developed by a core team including DF2ET and DJ7NT. This open-source project focuses on delivering advancements in both stability and functionality, specifically tailored for the amateur radio community. The application allows users to manage their radio logs from diverse environments, including professional servers, standard web hosting, or even compact _Raspberry Pi_ setups. The platform distinguishes itself through its emphasis on simplicity, robust features, and versatile accessibility, enabling operators to log contacts from virtually any location. It supports various operating modes and data formats, providing a flexible solution for tracking QSOs and managing station activities. The project's development is driven by the collaborative spirit of the amateur radio community, prioritizing utility and user experience over commercial objectives. Key features include comprehensive logging capabilities, support for multiple bands and modes, and integration with common amateur radio data standards, ensuring broad utility for DXers and contesters.

This document outlines the construction of a homebrew Buddipole antenna variant, designed for portable use and emergency services. The antenna utilizes telescoping whips and loading coils, enhancing its versatility across various HF bands. Key components include fiberglass rods, brass fittings, and Anderson Power Pole connectors, ensuring robust electrical connections. The design emphasizes non-inductive materials to minimize interference, while practical assembly techniques, such as epoxy and heat shrink tubing, are employed for durability. This variant aims to improve upon traditional Buddipole designs, offering greater strength and functionality.

Stop EMI RFI Interference in Off Grid Solar PV Systems, in this article the author provides hints on tracking down the EMI or RFI source, shielding and grounding in order to eliminate interferences on the whole HF and VHF ham radio bands

A cost-effective alternative to the Optibeam OB10-3W, a high-performance but expensive tri-band Yagi antenna for the 20, 17, and 15-meter bands. The original Optibeam, featuring three full-size elements on each band, delivers strong forward gain and front-to-back ratio but comes with a high price tag. To address this, a custom design was developed, offering similar performance at a fraction of the cost. Using accessible materials and a simple 1:1 current balun, the homemade version proved highly effective, making it a practical solution.

During radio's early days, high frequencies were under 30 MHz due to technical limitations. As understanding grew, components improved, allowing for higher frequencies like VHF and UHF up to 3 GHz. The HF band's long wavelengths provide unique propagation challenges influenced by solar activity. VHF and UHF bands face diffraction and reflection issues but offer diverse applications, from amateur radio to 5G and GPS technologies.

The Beverage on Ground (BOG) antenna offers ham radio operators a compact alternative to traditional Beverage antennas, requiring less space and fewer support structures. This implementation, optimized for 1.8-7 MHz bands, describes ideal parameters: lengths of 60-90 meters, height of 2-10 cm above ground, and specific load resistances based on configuration. The article details experimental methods for determining optimal load resistance and presents matching systems to convert BOG impedance to 50 ohms. While less effective than classic 200-300 meter Beverages, the BOG provides directional reception in limited space, though performance varies with ground conditions and weather changes.

DX Data provides a unified view of real-time DX spots, aggregating data from **DXSpider**, the **Reverse Beacon Network (RBN)**, and PSK Reporter. This online service offers advanced filtering capabilities, allowing amateur radio operators to refine spot displays by DXCC entity, band, mode, CQ zone, and continent. It addresses the challenge of sifting through numerous DX spots by presenting a consolidated stream, enabling DXers to efficiently identify active stations across various bands and modes. The platform integrates with Club Log, which assists in fine-tuning band-entity combinations based on a user's logging history, thereby reducing irrelevant spot noise. Key features include DX email alerts, PSK Reporter tracking, and a custom watchlist for monitoring specific stations or regions. The service also incorporates a live news feed from DX World, providing current information relevant to the DXing community. This design aims to streamline the DX spotting process, offering a responsive interface for identifying operating opportunities.

The small receiving loop (SRL) is a versatile and efficient antenna that can be simply built from common materials. It is designed for reception on the MF and HF bands and may be put in a variety of shapes and sizes. Despite its unusual installation, the porch loop in this case operated admirably, producing several DX spots on the 40m band. The SRL can be a great option for people looking to boost their reception on the MF and LF bands.

Discover how to easily listen to amateur radio bands with insights from Frank SWL, an experienced radio enthusiast. This guide covers essential tips for tuning into frequencies between 10 meters and 160 meters using modern tools like Web SDR and Kiwi SDR. Learn about identifying callsigns, understanding Q codes, and optimizing your antenna setup for better reception. Whether you're a beginner or an experienced listener, this article provides practical advice for enhancing your radio listening experience in 2025.

This presentation offers a beginner's guide to digital communication modes in Ham Radio, specifically PSK31 and RTTY. It covers the basics like what data modes are and the equipment needed (radio, computer, interface). It explains the technical details like PSK vs. RTTY, AFSK vs. FSK, and data transmission processes. The presentation also provides instructions on software setup, live testing procedures, and where to find data transmissions on different bands. Finally, it covers communication styles and etiquette for data QSOs.

OH2BH will be active on all bands up to April 17 2020

Effective suppression of harmonics and parasitic radiation from HF transmitters is crucial, especially with the increasing sensitivity of VHF/UHF radio channels to interference. This project details a hybrid low-pass filter (LPF) designed to operate across the HF bands up to 51 MHz, making it suitable for 6-meter band operations while providing deep VHF/UHF suppression. The design addresses the challenge of modern interference landscapes, where even microvolt-level signals can disrupt wireless sensors and other simple VHF/UHF receivers. The filter utilizes a single elliptic link, combining high cutoff steepness with robust suppression in the hundreds of megahertz range. A key feature is the use of only two standard capacitor values, simplifying construction and component sourcing. The article provides a detailed schematic, performance characteristics, and _RFSim99_ model file, demonstrating a reflection coefficient S11 below 0.017 (VSWR < 1.03) across 1-51 MHz, ensuring minimal degradation to the antenna system. Construction notes include coil winding specifications and capacitor selection guidance, with recommendations for _FR-4_ assembly. Two capacitor sets are presented, with the first variant recommended for its lower RF current demands, keeping currents below 3 A at 1 kW passing power at 51 MHz. Fine-tuning involves adjusting frameless coils, with considerations for capacitor tolerance and high-frequency capacitance measurement accuracy.

open890 is a web-based UI for the Kenwood TS-890S amateur radio, and features good usability, clean design, and high-speed bandscope/audio scope displays, among other features not available either on the radio itself, or in the ARCP remote control software. It is currently only designed to interface with the TS-890 via a LAN (or wifi) connection, and not a USB/serial connection. It may work with the TS-990, as the command set is very similar, but is currently untested.

Operating on the HF and VHF bands, the URE WebCluster serves as a real-time DX spotting network for amateur radio operators. It aggregates DX spots from various sources, presenting them with detailed information such as DX callsign, frequency, mode, and spotter details. The platform integrates essential propagation data, including current solar indices like _K-index_ and _A-index_, alongside visual propagation maps, which are crucial for planning long-distance contacts. Users can submit new DX spots, contributing to the collective intelligence of the amateur radio community, and filter existing spots by band, mode, or callsign, enhancing operational efficiency. This resource enables operators to monitor band openings and identify active DX stations, significantly aiding in _DXCC_ pursuit and contest operations. The integration of solar-terrestrial data directly within the cluster interface allows for immediate correlation between propagation conditions and observed DX activity, a feature not universally present in all web clusters. By providing both raw spot data and contextual propagation information, the URE WebCluster offers a practical tool for real-time decision-making during operating sessions, allowing hams to quickly adapt to changing band conditions and target specific _DX_ entities.

RUssian DXpedition Team is glad to annonce a trip to Kindom of Eswatini (Swaziland).Active on HF Bands 7-22 October 2021

A blog post about experimenting AI on writing blog post and creating pictures. This page includes also a youtube video by VE4VR experimenting ChatGPT over ham radio bands.

This website explains signal variations on a local radio net by tracking the foF2, a measure of ionosphere's ability to reflect radio waves. The website shows daily foF2 variations and how it affects Near Vertical Incidence Skywave (NVIS) propagation for local nets. It also considers D-layer absorption affecting lower bands and F2 MUF distance for long-distance communication. Additionally, the website tracks foEs for E-layer propagation and an EPI index for predicting Es chances.

This page offers a tool for hams to design vertical antennas for portable use on different HF/VHF/UHF bands. Vertical antennas provide omni-directional transmission and reception, making them ideal for DX contacts. By adjusting the antenna's dimensions and viewing radiation patterns and VSWR charts, hams can optimize performance in various terrains. The tool also accounts for the impact of sloping ground on elevation radiation patterns. Perfect for hams looking to enhance their portable radio setups and improve long-distance communication.

This project details the development of a modular direct conversion (DC) receiver designed for experimental flexibility in amateur radio and HF signal listening. The mainframe integrates a diplexer, DBM, and AF amplifier, supporting interchangeable local oscillator and antenna filtering setups. A tunable passive HF preselector complements QRP Labs bandpass filters for enhanced signal reception. Utilizing a NanoVNA for precise tuning, the receiver achieves improved signal-to-noise ratios across amateur and non-amateur bands, making it a versatile platform for further RF experimentation.

FT-240 toroids measurements. The data was measured using well-calibrated HP instrumentation. All plots have been adjusted to a frequency range of 1-100 MHz on the horizontal axis and a resistance/impedance range of 10-1,000 ohms on the vertical axis. This adjustment facilitates comparison among different materials and aids in determining their suitability for use on the HF ham bands.

Demonstrates the capabilities of DXtreme Monitor Log 14, a specialized software application designed for radio spectrum monitoring and logging. The resource details its core functionality, which includes logging stations across various bands and supporting multiple transmission modes such as AM, CW, FM, LSB, USB, and RTTY. It highlights features like the ability to select country formats for new databases and the **Schedule Checker** tool, which assists users in identifying broadcast stations for monitoring. The software facilitates tracking **Maidenhead grid squares**, particularly useful for VHF and UHF monitoring activities. It also supports QSL management and offers tools for efficient contact logging, catering to both amateur radio operators and shortwave listeners. Specific information includes its version number, Monitor Log 14, and its utility for DXers and other radio enthusiasts in managing their monitoring experiences and logging contacts effectively.

Rob Conklin N4WGY delivered an informative presentation on Hexagonal Beam antennas (Hex Beams), detailing their construction, performance, and benefits over traditional multiband Yagi antennas. He highlighted their cost-effectiveness, lower wind loading, lightweight design, and multi-band capabilities without requiring traps. Conklin also discussed the improved G3TXQ design, which offers better SWR performance across ham bands. The presentation included practical construction tips, resource recommendations, and demonstrations of performance analysis tools, making it a valuable resource for both novice and experienced antenna builders.

The POCKET TUNER V1.1 is a highly compact HF T-Match antenna tuner designed for QRPp and QRP portable operations. With a credit card-sized form factor, it is tailored for low-power setups, supporting HF bands from 10m to 40m. The tuner features a unique design using rotary switches for precise capacitor adjustments, allowing tuning in small increments. Its inductance selection is optimized for various bands, ensuring efficient performance. Equipped with a resistive tuning indicator, it protects the transmitter by reducing SWR during adjustments. This versatile and portable tuner is ideal for field operations, enabling efficient antenna matching for low-power rigs.

This page provides information on how to design an Off-Center-Fed Dipole (OCFD) antenna, suitable for amateur HF bands like 80 meters or 40 meters. The antenna design allows for VSWR minima on multiple bands, making it a good choice for multi-band use. Learn how to create an OCFD antenna in either flat-top or inverted-Vee form using a single support. The page also offers tools to generate radiation patterns, VSWR charts, and antenna current diagrams for your specific antenna design, helping hams understand performance factors. Ideal for ham radio operators looking to build their own effective antennas.

This document serves as a thorough guide to amateur radio nets throughout Australia and includes some international (DX) nets. It outlines key information like frequencies, schedules, and the people responsible for managing these nets. Among the nets covered are Ron's 10 A.M. net, the Australian Travellers Net, and several others, each operating on different bands and regions. Additionally, it offers technical details about repeaters, such as frequency, offset, and CTCSS tones where applicable. Any updates are clearly marked, and further details are included for linked repeater systems and network connections.

This page provides information on solar conditions and their impact on ham radio propagation, specifically focusing on the HF bands. A daily graph show the predicted solar flux and Kp Indexes

This **PDF report** documents a _maritime mobile_ DXpedition operating from the _Southern Ocean_ near Antarctica, detailing antenna deployment strategies on a sailing vessel. It addresses power management systems for remote operations and propagation characteristics specific to polar regions on **20m and 40m** bands. Operational strategies include managing high-density pileups using split frequency operation and maintaining signal integrity during periods of high aurora activity. Equipment considerations cover specific transceiver models like the Icom IC-7300, antenna types optimized for marine vessel installation, and battery power systems for extended periods without shore power. The resource also examines the use of satellite communication for real-time log uploads and QSL confirmation from remote locations, and discusses mitigating signal degradation from ice accumulation on antennas. DXZone Focus: PDF report | Maritime Mobile DXpedition | Polar Propagation | Split Frequency Operation

Operating amateur radio repeaters involves understanding frequency offsets, CTCSS tones, and the basic signal flow through a repeater system. This resource details the fundamental concepts of repeater operation, including the distinction between input and output frequencies, the role of **CTCSS (Continuous Tone-Coded Squelch System)** for access, and the typical frequency bands utilized for local communication. It clarifies terms such as "simplex" versus "duplex" operation and provides a diagram illustrating the signal path from a handheld transceiver to a repeater and back to another station, emphasizing the range extension repeaters offer. The article further explains practical aspects like identifying a repeater's offset (e.g., +600 kHz for 2-meter band) and the necessity of programming the correct tone. It compares the operational benefits of using repeaters for local communication over direct simplex contacts, highlighting how repeaters overcome line-of-sight limitations. The content is structured to assist new licensees in confidently making their first repeater contacts, providing a foundational understanding of how these critical infrastructure components facilitate wider area coverage for VHF/UHF amateur radio.

The Central States VHF Society, Inc. (CSVHFS) is a not-for-profit organization chartered in the state of Missouri. It was begun in the mid-1960s to foster amateur radio operation on the bands above 50 MHz.

This page provides instructions for unlocking additional frequency bands on your IC-7610 transceiver to access the 60m band. The step-by-step guide is useful for hams looking to expand their operating capabilities and communicate on this popular band. By following these instructions, you can ensure that your transceiver is set up correctly to operate within the regulations of the 60m band.

An FT-817 ceased transmission on the VHF 2m band, despite the other HF, UHF, and 50 MHz bands operating correctly. Suspecting an excess of input signal during FT-8 mode transmission, they conducted measurements with an oscilloscope, revealing a burnt-out PIN diode, identified as D3003, type HSU277, on the PA unit board. Following the replacement of this surface-mounted diode, their FT-817 resumed operation on the 144 MHz band.

High Frequency (HF) radio propagation, particularly the phenomenon of "Skip," which enables long-distance radio contacts, is thoroughly explained for newcomers to the amateur radio hobby. The article begins by defining essential terms such as _radio signal_, atmosphere, troposphere, stratosphere, mesosphere, thermosphere, exosphere, and aurora, setting a foundational understanding for subsequent discussions. A significant portion of the content focuses on the ionosphere, identifying it as the primary driver of HF propagation. Its structure, including the D, E (E1, E2, E3), and F (F1, F2) layers, is detailed, along with how solar radiation influences these layers to refract radio waves back to Earth. The concept of "The band is opened!" is introduced, specifically noting refraction around **21 MHz**. The guide also touches upon ground waves, space waves, and temperature inversions affecting VHF/UHF propagation, contrasting them with the dynamic nature of ionospheric HF propagation. Factors like antenna polarization, takeoff angle, and the sun's solar cycle are mentioned as critical influences on signal path, with examples like 80-meter band propagation after sunset and 40-meter/20-meter bands offering near-constant propagation.

This project involved designing a 7-pole Chebychev broadcast band filter to address severe interference issues caused by a new horizontal loop antenna on the KN-Q7A transceiver. The interference overwhelmed the transceiver’s front end, so a custom filter with a 3.5 MHz cutoff was built using silver mica capacitors and type 6 T130 toroidal cores. Encased in a diecast box with SO239 sockets, the filter blocks strong signals from the broadcast band, achieving over 100 dB attenuation. Tested up to 100W, it reduces interference effectively while maintaining low insertion loss across HF bands.

This article from the July 1976 issue of Radio REF discusses the trend of large antennas for ham radio operators on the low bands. It specifically focuses on a Yagi 2 element antenna for the 80m band, detailing its construction and functionality. The author explains how the antenna can be switched between directing signals towards the West or East using a switch at the station. The article also provides technical details on the lengths of the director and reflector elements, and how they impact the antenna's performance. A useful resource for hams looking to build or understand Yagi antennas for the 80m band.

Ham radio communication in the VHF and UHF bands, which was previously dominated by analog Frequency Modulation (FM), is increasingly incorporating Digital Voice (DV) modes. DV transceivers digitize audio and offer benefits like as signal integrity, encoded caller ID, and bandwidth savings. Today D-STAR, DMR and Yaesu System Fusion (YSF) are popular DV formats, each with its own set of features but mainly incompatible with the others. Internet access with Voice Over Internet Protocol (VoIP) expands DV communication worldwide. Repeaters and personal hotspots expand DV capabilities, enabling seamless worldwide connections. However, implementing DV frequently necessitates learning new technologies and negotiating network complexity.

A full-wave delta loop antenna, approximately 141 feet in total wire length for the 40-meter band, offers a low angle of radiation, which is highly advantageous for DX operations. This design, optimized for both 30m and 40m, leverages a specific circumference calculation of 1005/F, ensuring resonance on both bands through a simple switching mechanism. The antenna's configuration enhances long-distance communication, making it a practical choice for hams with limited space. The resource details the construction process, including the use of a _Ceramic Knife Switch_ for band selection and an _RG-11_ matching section to achieve optimal impedance. It outlines the precise loop lengths required for each band, along with tuning secrets to ensure efficient operation. Requiring a minimum height of 12 feet, this antenna can be supported by a single mast or tree limb, making it suitable for suburban installations where stealth or space constraints are a factor.

DK4MJ's blog details numerous POTA activations and outdoor amateur radio operations, predominantly from Germany. The content focuses on practical experiences in the field, often involving portable setups and antenna deployments for various bands. Articles frequently describe specific station configurations, power sources, and operational challenges encountered during activations. Many entries include photographs of the operating environment and equipment, such as _portable antennas_ and transceivers, providing visual context to the operational narratives. The blog serves as a personal log of amateur radio adventures, sharing insights into effective portable operating techniques and station optimization for remote locations. Regular updates cover recent activations and related amateur radio topics.

The International DX Amateur Radio Club provides a structured environment for amateur radio operators interested in long-distance communication. The club offers a variety of awards, including the DX Countries Award, DX United States Award, and DX Continents Award, among others. These awards recognize achievements in contacting stations across different geographical areas, such as Europe, Africa, South America, and Asia. The club also supplies resources like DX Spots, Grey Line Map, and Solar Data to assist operators in optimizing their communication strategies. The DX Code of Conduct emphasizes disciplined operating practices. Operators are encouraged to listen carefully before transmitting and ensure they have correctly identified the DX station's call sign. The guidelines advise against interfering with ongoing communications and stress the importance of patience, such as waiting for the DX station to complete a contact before calling. Operators are reminded to send their full call sign and avoid continuous calling, maintaining respect for fellow operators to foster a cooperative amateur radio community. DXZone Technical Profile: DX Awards | DX Code of Conduct | Grey Line Map

This is a theoretical look at propagation on 630-Meters and 2200-Meters using ray tracing software. It expands on the brief discussion in the ARRL Handbooks. The Earth's magnetic field affects 630-Meter and 2200-Meter band propagation. Lower ionization reduces absorption, aiding low-frequency propagation. Differences exist between bands, limited daytime sky-wave propagation. Sunrise/sunset show promise, yet mechanisms are unclear. Ducting possible at night in specific conditions. Negative ions enhance propagation. Inefficient antennas and high man-made noise are anticipated. Groundwave propagation is significant on 2200-Meters.

Antenna project for a home made quagi antenna for UHF Bands, 432 MHz. This projects is done using some aluminium bar rods and includes design and pictures of the project

Single Sideband (SSB) operation requires careful attention to the relationship between a radio's displayed frequency (suppressed carrier) and the actual 3 kHz wide audio signal. This resource clarifies how Upper Sideband (USB) and Lower Sideband (LSB) signals occupy spectrum above or below the indicated frequency, respectively. It provides practical examples for General Class operators on the **20m** and **40m** bands, such as setting a VFO to 14.226 MHz for USB on 20m or 7.178 MHz for LSB on 40m, to maintain a safe margin from band edges. The resource emphasizes the critical importance of staying within allocated band limits to prevent out-of-band emissions, particularly when operating close to band edges. It includes relevant excerpts from **FCC Regulation Part 97**, specifically section 97.307, which details emission standards, necessary bandwidth, and spurious emission attenuation requirements. The text explains that unused sidebands are considered spurious emissions and notes that modern HF equipment typically exceeds the 43 dB spurious emission reduction standard, often achieving 60 dB or more.