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Accurately determining an antenna's feedpoint impedance is crucial for optimal performance, especially when experimenting with new designs or making adjustments. While SWR meters provide basic information, a full complex impedance measurement reveals the resistive and reactive components, which are essential for proper matching. Modern antenna analyzers, like the _Palstar ZM30_ or MFJ259B, simplify this task, but measurements taken through a transmission line require careful interpretation due to impedance transformation. This resource details a calibration method to precisely account for the effects of the feedline. It explains how a transmission line can significantly alter the measured impedance, illustrating this phenomenon with a Smith Chart example where an 80m antenna's [22 + j6] Ohms feedpoint impedance transforms to [82 + j45] Ohms after a 10m line. The guide demonstrates using a transmission line calculator applet, such as the one by W9CF, to reverse this transformation. It outlines the process of calibrating a specific length of RG174 coax, showing how an initial 26ft estimate was refined to **25.85ft** to accurately predict a known 22 Ohm load, significantly improving accuracy over uncalibrated results.

Ham Radio Class On-Line. A complete On-Line Course for the Technician, General or Extra Class amateur radio license.

Bird Technologies supplier of RF products, like RF Meters, Bird 43, VNA, Spectrum analyzers, attenuators, transmitters combiners, dummyloads, terminators and replacement parts

Packet-Radio-Controller for amateur radio, CB and commercial applications. Data radios (transceivers), receivers and transmitters for high speed data communication Assemblies for satellite ground stations, special receivers and transmitters.

Key your transmitter from the tone output of a Morse Code generator program

Analyzing FCC amateur radio license issuance data, this resource presents monthly graphs and raw numerical statistics detailing the number of new and upgraded amateur radio licenses. The primary focus is on the impact of the Element 1 Morse Code test removal on HF privileges, specifically observing the transition rates from _Technician_ to _General_ and _Extra_ class licenses. Data is sourced from _QRZ Archives_ and processed using a custom Perl script to tally "Issued" licenses each month. The presented data, available in graphical, tabular, and raw XML formats, clearly illustrates the "spike" in General class upgrades following the rule change. It also highlights a consistent rise in new Technician licenses observed in March of both 2006 and 2007. While the dataset currently extends back to January 2006, providing a limited statistical snapshot for long-term Technician trends, it effectively captures the immediate climb in General class licenses.

Part 2 - Ten-Tec Jupiter CW copying and keyboard transmit

Iphone app for ncdxf IARU beacon monitoring, shows the currently transmitting beacon on each band, reception charts from the active monitoring stations, and latest solar flux A and K indices

Your source for weather radios, communication headsets, 14 channel radios, M&M groovy radios, smithsonian crystal radio and weather station kits, line restrictors, antennas,ham radio accessories, and battery products.

How to build a simple WSPR beacon using the Raspberry Pi for the transmitter

A Smith charting program. You can enter either discrete components or transmission lines, see the results on screen and/or generate Postscript output. Component values can be changed numerically or using scrollbars.

A compact antenna for 160 meters, suitable for hams tha want operate top band buh have a limited space

A radio's transmitting power can be concentrated along the horizon by use of a GAIN antenna. Although you may still be transmitting with four watts of power, your effective radiated powerwill be greatly increased. This table shows the effects of antenna gain on a transmitter with 4 watts of transmit power.

Presents a dedicated online callbook for Romanian amateur radio operators, compiling an extensive database of YO callsigns. It details information sourced from the _Agentia Nationala de Comunicatii_ (ANCOM) and user submissions, including callsigns, names, postal addresses, email contacts, and even photographs. The resource currently lists **10,768** YO callsigns, with **4,987** authorized by ANCOM, offering a centralized lookup for the Romanian amateur radio community. This platform also includes special event callsigns like _YR8D_, acknowledging their importance for QSL information sought by international DXers. It provides categorized lists of YO hams by county, a section for SWLs (radioamatori receptori), and a directory of YO radio clubs and associations. Users can submit updates or corrections via an online form, with validation typically processed quickly, often within minutes, ensuring the database remains current.

Displays amateur radio grid squares worked from third-party logging programs, providing a visual representation of contacts on a world map. This Windows application uses colors to differentiate up to four bands concurrently, calculating the total number of grid squares worked per band. It reads plain-text log files, including fixed-width, character-delimited, ADIF, and Cabrillo formats, dynamically updating the map as log files are saved during contests or general operation. Primarily targeting **VHF** and above operators, WorkedGrids aids in grid square collection for contesting and awards. The software offers a fixed-resolution continental viewpoint, zoom-in capabilities, and supports printing or copying the map to the clipboard. It operates on Windows 95 through Windows 11, requiring minimal CPU and RAM, and features a non-invasive installation. The program has undergone several updates, with version 7 released on March 3, 2024, addressing minor fixes and improving stability.

Operating an amateur radio station often involves community engagement, and the Anne Arundel Amateur Radio Club (AARC) exemplifies this with a focus on public service and emergency communications. The club maintains repeaters, provides an Elmer program for new hams, and conducts training and testing sessions, fostering skill development across various age groups and experience levels. Members participate in activities ranging from contesting to kit building, promoting technical proficiency and camaraderie within the local ham radio community. The AARC hosts regular meetings on the first and third Thursday evenings, creating opportunities for fellowship and knowledge exchange. Their commitment extends to programs designed for kids, YLs, OMs, and both new and experienced operators, ensuring a broad appeal. This club's structure supports continuous learning and practical application of amateur radio principles, aligning with the core values of the hobby. Their emphasis on emergency preparedness highlights a critical aspect of amateur radio's public service mission.

How Vacuum Tubes Really Work. Vacuum tubes rely on hot cathodes emitting electrons and a plate attracting them to create current. A grid in between controls the current flow, enabling amplification. This article explores the nitty-gritty of how it works, including how cathode type, temperature, and electrode spacing affect the process. It explains the physics behind electron emission, space charge, and amplification factor, offering a deeper understanding than the basic principles.

ARRL's Logbook of the World (LoTW) system is a repository of log records submitted by users from around the world. When both participants in a QSO submit matching QSO records to LoTW, the result is a QSL that can be used for ARRL award credit.

RFAC Solutions specializes in providing a range of RF components, including various connector types, cable assemblies, attenuators, and filters. Their product line features common connector standards such as SMA, BNC, TNC, N-Type, MCX, and MMCX, essential for reliable RF signal paths in amateur radio and commercial applications. The company also offers high-power VHF amplifiers, catering to needs for signal boosting in specific frequency ranges. Their offerings extend to dust caps and adapters, which are crucial for maintaining the integrity and versatility of RF systems. The focus on supplying components from South Korea suggests a commitment to specific manufacturing standards and supply chain practices. This resource details a vendor's product scope, useful for hams sourcing specific parts for shack builds or antenna projects. Jeff is listed as a contact for inquiries.

The International DX Association is an amateur radio organization dedicated to working DX and making DX possible. Promotes and supports DX operations in countries that have limited or no amateur radio activity. Support is usually to DXpeditions to rare DXCC entities. Provides DX news and QSL routes on 14.236 MHz at 2330z.

This short dipole antenna has been described by Nadisha, 4S7NR and may be of interest to anyone wishing to get on 80M (3.5MHz) that have limited space available.

Radio frequency systems require robust protection against transient voltage events, which can severely damage sensitive equipment. This resource details a range of **RF surge protection** devices, including models with DC Pass, DC Block, Bias T, and Ultra Low PIM characteristics, designed to safeguard critical infrastructure. It also presents various RF filtering solutions and interconnect components, emphasizing their role in maintaining signal integrity and operational continuity across diverse applications. The site provides information on products engineered for both RF and data line protection, highlighting their utility in preventing downtime and equipment loss. Specific product categories encompass coaxial protectors, grounding items, and fiber optic solutions, indicating a broad scope of application from amateur radio installations to industrial and telecommunications networks. Furthermore, the resource mentions the availability of NOM-certified products and offers same-day shipping for many items, underscoring a commitment to rapid deployment and compliance with industry standards.

The NCDXF/IARU International Beacon Project operates a worldwide network of 18 high-frequency radio beacons, continuously transmitting on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. These beacons, initially launched in 1979 with a single station and expanded to the current 18-beacon system in 1995, provide reliable signals for both amateur and commercial users to assess current **ionospheric propagation** conditions. The system's design, construction, and operation are managed by volunteers, covering hardware and shipping costs. The resource details the evolution of the beacon network, including the transition from Kenwood TS-50s transmitters to Icom IC-7200 radios with a new controller design implemented in 2015. It explains how listening for these 100-watt signals, transmitted to vertical antennas, allows operators to determine band openings and optimal propagation paths globally. The content also references three QST articles providing historical context and technical specifics of the beacon project. Practical information includes methods for identifying transmitting beacons via a schedule or specialized software like FAROS and Skimmer, which integrates with the **Reverse Beacon Network** for automated monitoring.

IC7100BKT is a free program to control the Icom IC-7100 transceiver for MS Windows, available in free version with limited functions and full donationware version.

Maker of QRP Kits, QRP CW receiver and transmitters, audio CW Filters, antenna tuners, dummy loads, and morse code practice oscillator

One another useful Table for the HAM's practice.

Details the Northern Amateur Relay Council of California (NARCC) as the regional coordinating body for amateur radio repeaters operating on the 10-meter band and above. It outlines NARCC's function in managing frequency allocations to minimize interference and ensure efficient spectrum use across Northern California. The resource specifies that NARCC operates in cooperation with the FCC and ARRL, indicating its recognized authority within the amateur radio community. The organization's role centers on repeater coordination, a critical aspect of VHF/UHF operations where multiple stations share limited frequency segments. It highlights the support received from local amateur radio operators, underscoring a community-driven approach to spectrum management. The site serves as a primary reference for hams seeking to establish or operate repeaters within the designated service area. NARCC's activities directly impact the operational landscape for _VHF_ and _UHF_ enthusiasts, providing essential guidelines and coordinated frequencies. This ensures orderly communication and prevents conflicts, particularly in densely populated areas of Northern California.

TurboLog is a station management and logging program designed for amateur radio operators, providing robust database and logging functionalities. It features fully integrated support for controlling typical radio station equipment, including transceivers, packet radio TNCs, Morse and voice keyers, and digital mode terminals. The software also incorporates antenna switching capabilities and acoustic alerting, streamlining station operations for DXing and contesting. The program's utility extends to award tracking for entities like DXCC and IOTA, alongside comprehensive callbook and ham database integration. It supports log import and export, QSL label generation, and includes TNC drivers for packet radio. The trial version allows users to evaluate its extensive features before commitment, making it a versatile tool for managing complex amateur radio station configurations and operational data.

For amateur radio operators engaged in **radio direction finding** (RDF) and **transmitter hunting** (T-hunting) activities, this resource provides a catalog of printed circuit boards (PCBs) for constructing various DF and foxhunt-related projects. The offerings include PCBs for 80-meter fox transmitters and receivers, UHF fox transmitters with audio recording capabilities, and several designs for general-purpose radio direction finders. Specific projects like the "Simple 80M ATX-80 Transmitter" and the "N0GSG DSP Radio Direction Finder" are listed, along with attenuator boxes and specialized components for Doppler DF systems. The catalog details PCBs for projects published in prominent amateur radio magazines such as *73's*, *CQ*, *QST*, and *PE*, indicating their origin and design pedigree. For instance, the "Montreal Fox Controller" is sourced from the *Homing-In* column by Joe Moell, K0OV. The resource also lists components for advanced Doppler DF systems, including main boards, LED display boards, and antenna switch boards, with options for programmed PIC microcontrollers. Pricing for each PCB is provided, allowing hams to acquire the necessary components for their DIY RDF endeavors.

40 meters band 5 watts transmitter, uses a 6L6 with a 6X5 rectifier and a 0D3 voltage regulator tube on the screen.

Optimizing a G5RV or ZS6BKW multiband wire antenna for HF operation often involves addressing common SWR issues and understanding feedline characteristics. This resource chronicles the construction and performance evaluation of a G5RV, initially built for 80m, 40m, 15m, and 10m bands, by a newly licensed Foundation operator. The author details the selection of materials, including 3.5 mm stainless steel wire for the doublet arms and enameled copper wire for the open-wire feeder, and the initial decision to omit a balun based on common online information. The narrative highlights the initial disappointing performance, characterized by high receive noise and poor signal reports on 80 meters, despite the transceiver's internal ATU achieving a 1:1 match. This led to experimentation with a coax current balun and further research into G5RV myths, such as SWR claims and the necessity of a balun. The author then describes modifying the antenna to the ZS6BKW configuration, which involves specific changes to the doublet and feedline lengths, and integrating a 1:1 current balun wound on a ferrite toroid. The modifications resulted in improved reception and transmit performance across the bands.

DXPocketâ„¢ is a fast, stable, low-traffic, and easy-to-use DX Cluster program for Android-powered smartphones and devices. DXPocket monitors the DX Spots and Announcements available on the Internet at DX Summit web site and presents the information in a sortable grid format. With a few taps you can find a required station in the Cluster, obtain DXCC information of selected DX, send DX Spot or Announcement.

Hidden transmitter hunting, often called fox hunting or Amateur Radio Direction Finding (_ARDF_), presents a unique challenge for radio amateurs. This resource details the _PicCon_ controller, a specialized device designed to automate the transmission of signals for such events. It integrates with a standard radio transceiver, functioning similarly to a packet radio TNC, by controlling the Push-To-Talk (PTT) line and injecting audio tones or modulated CW Morse code into the microphone input. The _PicCon_ unit is field-programmable using DTMF tones received via the radio, storing all settings in EEPROM for power-off retention. Its compact design and low power consumption (a few milliamps from a 7-35VDC source) make it suitable for remote deployment. An onboard LED indicates operational status, and a push-button allows manual start/stop of transmissions without DTMF. Typically supplied as a kit, _PicCon_ includes a PCB, components, and a comprehensive manual (available in HTML, RTF, and PDF formats). The kit provides a six-conductor interface cable, but users must supply radio and power plugs due to varied configurations. Byon, _N6BG_, developed this controller, which is available from the Byonics website.

Presents a curated collection of newsletters dedicated to _Earth-Moon-Earth_ (EME) communications, primarily focusing on the 432 MHz band and higher microwave frequencies. The resource details various EME DX experiences and news contributions from operators like K2UYH (W6/PA0ZN), offering insights into successful moonbounce contacts and operational strategies. It serves as an archive of specialized content for those engaged in or interested in extreme weak-signal propagation via the moon. The newsletters provide practical information on achieving EME contacts, often including details on station setups, antenna arrays, and signal reports from challenging DX. For instance, operators might report achieving contacts over **750,000 km** round trip, demonstrating the feasibility of long-distance communication on UHF and microwave bands. The content differentiates itself by concentrating on the unique technical and operational aspects of EME, which contrasts significantly with terrestrial DXing, providing a specialized knowledge base for advanced amateur radio operators.

Emits daily 24 hour shortwave radio broadcast from Spain and targets international listeners who wish to find out about Spain and also Spaniards living abroad, who wish to keep abreast of news at home.

Demonstrates a practical online tool for locating amateur radio operators by geographic area, specifically using US ZIP codes. This utility allows users to input at least three digits of a desired ZIP code to retrieve a list of active licensees. Search results can be sorted by _call sign_, name, license expiration date, or ZIP code, providing flexibility in data organization. The service offers two primary output formats: direct display in a web browser, which omits address details for privacy, or export to a tab-delimited file, which includes full address information suitable for import into spreadsheet or database applications like _Excel_. This lookup service proves useful for local club organizers seeking to identify potential members within their service area or for hams planning local nets or events. The ability to export data with address details facilitates direct mailings for club newsletters or event announcements, while the browser view maintains privacy for casual lookups. The tool's design prioritizes ease of use, requiring minimal input to generate relevant local amateur radio contact information.

Presents a QRP AM/CW transmitter project specifically designed for the 10-meter band, utilizing a crystal oscillator and a collector-modulated AM oscillator. The design employs a 2N2219(A) transistor in a Colpitts configuration, generating 100 to 350 mW of RF output power depending on the 9-18 Volt supply voltage and modulation depth. Frequency stability is maintained by a 28 MHz crystal, with fine-tuning possible via a Ct1 trimmer capacitor for approximately 1 kHz adjustment. The resource details the RF oscillator stage, implemented with a 2N2219 NPN transistor, emphasizing frequency stability and low power dissipation. It also covers the amplitude modulation stage, managed by a 2N2905 PNP transistor, which impresses audio information onto the carrier. Selective components (C3, C4, C7, C5) enhance voice frequencies within a +/- 5 kHz bandwidth, and modulation depth is controlled by R2 and R3. The project includes a 3-element L-type narrow bandpass filter (Ct3, L3, C10) to suppress harmonics and ensure a clean output signal. The project provides a complete schematic diagram, a comprehensive parts list including specific capacitor, resistor, and inductor values, and construction notes for the coils (L1, L2, L3). It also offers practical advice on enclosure requirements, suggesting an all-metal case or a PVC box with graphite paint for RF shielding. Operational parameters such as current draw (27mA@9V to 45mA@16V) and input impedance (50 Ohms) are specified, alongside guidance on antenna matching and the importance of a valid amateur radio license for 10-meter band operation.

A switchable Magnetic Transformer for Transmitting for various impedances

The ZS6BKW multiband antenna, an optimized variant of the classic G5RV, features a 102-foot (31.1 m) horizontal span and a 39.1-foot ladder line matching section. This design, derived by G0GSF (formerly ZS6BKW) in the early 1980s using computer programs and _Smith charts_, aims for improved SWR across multiple HF bands compared to its predecessor. Construction details specify Wireman 554 ladder line and #14 AWG THHN copper wire for the radiators, with precise instructions for determining the velocity factor (VF) of the ladder line using an antenna analyzer or dip meter, ensuring accurate physical length for the matching section. The radiator length is electrically 1.35 wavelengths for the 20-meter band, requiring careful trimming during tuning. Field measurements with an _AIM-4170C_ analyzer by KI4PMI and NC4FB demonstrated good SWR curves and bandwidth on 6, 10, 12, 17, 20, and 40 meters. The antenna was deemed unusable on 15 and 30 meters due to very high SWR, but an LDG AT-100PRO autotuner successfully brought 6 and 80 meters into tune. Contacts were made on 80, 40, 20, and 17 meters, including a **17-meter** contact to Spain. EZNEC models for 80-6 meters are provided, along with an AutoEZ model by AC6LA, which predicted good SWR for 80-10 meters. W5DXP's modifications for an all-band HF ZS6BKW are also referenced.

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

Deutschen Amateur Radio Club Awards

Live DX spots are presented through a _web cluster_ interface, utilizing both a world map and a Google Maps display for visualizing amateur radio propagation. The system provides real-time spotting data, enabling operators to track active stations globally. Users can observe current band conditions and station activity, which is crucial for optimizing contact strategies across various amateur bands. The platform's utility extends to contest operations and general DXing, offering a visual representation of where stations are being heard. While the primary function is DX spotting, the site also includes technical articles, such as instructions for interlocking two Flex Radios for single-transmitter compliance in contests, and a guide for constructing a simple **5KW** 1:1 balun for **160m/80m** dipoles using RG400 cable. This combination of live data and practical technical content supports both operational awareness and station improvement.

This modification will allow the use of separate receive and transmit antennas on the Kenwood TS-850S/AT.

The Micro24 is a ultra compact microsize QRP SSB transceiver for the 20 meters amateur radio band. This transceiver is so small that it fits into one hand.

A free radio station that is transmitting world wide on several shortwave frequency 's with loads of pirate and freeradio information.

Operating on the 2200m band (135.7-137.8 kHz) often presents challenges for amateur radio transceivers, which typically exhibit poor receiver performance at these very low frequencies. This project addresses the issue by providing a design for a dedicated 137 kHz antenna preamplifier, specifically tailored to improve signal reception for radios such as the _Yaesu FT-817_. The preamplifier circuit utilizes a low-noise FET input stage, crucial for minimizing self-generated noise and maximizing the signal-to-noise ratio from weak LF signals. The design includes a detailed schematic, component values, and construction notes, enabling homebrewers to build a functional unit. The goal is to achieve significant gain, making the faint signals on 2200m more discernible and improving overall band usability. Key design considerations include impedance matching to typical antenna systems and ensuring stable operation across the narrow LF segment. The circuit aims for a **low noise figure** and sufficient amplification to overcome the inherent limitations of general-purpose HF transceivers when operating below **200 kHz**.

Antique Radio Tubes Sell antique radio tubes, over a thousand different radio tubes in stock

A very efficient 80 meter Counterpoise antenna designed to reduce ground losses from inadequate radial systems beneath inverted L antennas, a project by DM2GM and DM4IM based on the original K2AV antenna concept.

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

The Elecraft K2 transceiver requires specific modifications for optimal soundcard digital mode operation, particularly for PSK31. The original article, circa 2001, details initial challenges with manual PTT and speech compression settings. A key modification involves adding headphone audio and a compression disable signal to the K2's microphone jack, utilizing pins 4 and 5. The **COMP0** signal, active low, is shorted to ground via a non-inverting open collector switch circuit, comprising two resistors and two transistors, mounted on the SSB board near U3. This circuit provides effective control of an analog signal line with good noise immunity. The switchbox itself repurposes a computer COM port switch, using only two of its original connectors and four of the nine poles. It integrates a microphone preamplifier, a PTT circuit built with 'flying leads' construction, and RCA jacks for soundcard connections. A trimpot adjusts the audio drive to the K2. The central DB9 connector links to the K2's mic connector via a shielded RS232 serial cable, ensuring proper grounding and signal routing. An external footswitch PTT jack is also included. Further enhancements include a **noise-canceling microphone** preamp based on a QST December 2000 article, adapted for Heil mic elements. This preamp, built with pseudo-Manhattan style construction, provides a gain of approximately 2 by changing emitter resistors (R9 and R16) from 680 ohms to 330 ohms. A 10-ohm series resistor and 47 µF capacitor on the +5V supply mitigate noise spikes.