Search results

Diplexer is a passive device, a special filter circuit that seperates 2 different bands, not to be confused with the duplexer that usually separate 2 different frequencies on the same band.

How to build a slingshot antenna launcher. Slingshot antenna launchers are used to launch a line over a tree branch, so antennas can be suspended from high up trees

HB9MTN loop motor control software. For motor control, either Centronics, RS232 or USB ports can be used, for CAT-Control the RS232 or USB ports.

Otto engineering is comprised of two divisions otto controls and otto communications. otto controls designs and manufactures a full line of switches and grips used in heavy equipment, aerospace, marine, medical and other demanding applications. otto communications designs and manufactures audio accessories for two-way radios used in public safety, police, fire, retail, hospitality manufacturing and other markets.

This is an Android application used to remotely control several HAM radio Web SDR or any CAT enabled transceiver

Over two decades ago, the Kenwood TS-850S HF transceiver established itself as a robust performer, known for its excellent receiver and versatile operating features. This vintage rig, often found on the used market, continues to be a favorite among many amateur radio operators for its solid construction and reliable performance across the HF bands. Adrian's Yahoo! Group provided a dedicated forum for TS-850S owners to exchange insights, troubleshoot issues, and share modifications or operational tips. Such community-driven platforms were crucial for extending the operational life and maximizing the utility of classic transceivers, fostering a spirit of mutual aid among hams. Discussions frequently covered topics like DSP unit upgrades, common repair challenges, and optimizing the rig for contesting or DXing, reflecting the enduring interest in this particular Kenwood model.

Sherwood Engineering Inc. (SEI) offers a repository of technical presentations and white papers focused on optimizing amateur radio transceiver and receiver performance. Content includes detailed analyses of _roofing filters_, transmitted IMD, and receiver characteristics, with specific discussions on products like the Drake R-4C and Icom IC-781. Presentations from events such as Dayton Contest University (2008-2014) cover topics like "How To Optimize Rig Performance," "Transceiver Performance: 10 Years of Change," and "Choosing a Transceiver: Far from Simple." Additional white papers address HF mobile antenna efficiency, ground screen alternatives to buried radial systems, and common receiver problems with solutions. The site also provides historical product information for items like the SE-3 MK IV synchronous AM detector and various 455 kHz mechanical and crystal filters, though many products are no longer in production. Receiver test data and alignment tips for the R-4C are also available, offering insights into rig modifications and performance enhancements.

This type of filter can be used in a Mode J satellite station (uplink on 2m, downlink on 70cm) to reduce the problem of the uplink signal desensing the receiver

Here is a review of the 40 and 80 meter band Double Bazooka antennas as used on the HF shortwave bands.

Useful exercise sheet to learn morse code reception. In A4 format PDF File, it contains groups of 5 characters commonly used while learning morse code reception.

Delta 160-meter receiving antenna used at FO0AAA

Coaxial stub filters used at W7GJ

This voice-keyer-interface connects between a Yaesu FT1000MP and a PC's sound card & COM port. It can be used as a voice-keyer with Contest Voice Blaster and as a voice-keyer and CW-keyer with Writelog.

With this tool it is possible to create QSO maps overlay on Google maps there each QSO get a line from the home location to each DX location. An EDI logbook file is used as input. The creation will only use complete locator in the 6 characters format.

Explore this high-resolution ITU Zones Map, a critical reference resource for amateur radio operators, international broadcasters, and telecommunications engineers. Originally established by the International Telecommunication Union – Radiocommunication Sector (ITU-R) Broadcasting Services Division (1999), this chart accurately divides the globe into 90 specific CIRAF zones. This authoritative visual guide is indispensable for planning High Frequency (HF) radio propagation, scheduling international broadcasts, and verifying locations for radio contests and awards. Distinct from the 40 CQ Zones, the ITU zoning system provides the official administrative framework used for global frequency management. This digitally enhanced version ensures maximum clarity of zone boundaries and numbering (e.g., Zone 28 for Central Europe), making it an essential tool for technical accuracy in logbooks and station management. It serves as a trustworthy standard for educators, hobbyists, and industry professionals alike.

Welcome to the Amateur Television Directory, the source for finding sites related to Amateur Television and Ham Radio. Find out where Amateur Television is being used in your state or country.

The antenna was built to be used for shortwave listening with a Tecsun PL-660 radio receiver. Later it was used with Yaesu VX-6 handheld transceiver and with Yaesu FT-817ND for shortwave listening.

Ferrite rod antenna or aerial, a form of RF antenna that is widely used in RFID and transistor radio applications.

An online morse game that can be used both to learn receivind and trasmitting morse code

This scheme can be used to combine two antennas

Ideas and notes on designing a SO2R radio shack room. Includes lots of radio shack pictures used by K8ND as ideas to plan his new radio shack, with contesting in mind.

A simple portable VHF ground plane antenna project used for ARES activities

A selection of alphabets used, particularly by ham radio operators, to spell out words

80 to 6 meters, 2 KW, designed to be used at heights of only 25 to 45 feet, includes a twenty foot long vertical radiator

History of codes of the world, russian codes, visual codes, and al long collection of telegraph codes as used worlwide including the international morse code and the relative variations

New and used books on telegraphy, key collecting, antique radio and communication-related subjects, as well as vintage telegraph instruments

The County Hunting software, version **6.1**, is designed for amateur radio operators focused on USA-CA Award tracking and logging. This application supports _Windows_ environments and facilitates the import and export of ADIF files, enhancing QSL management by integrating electronic confirmations via LoTW and e-QSL. The software has been updated to align with the new award rules managed by MARAC, following the discontinuation of CQ magazine's involvement. Users can visualize QSLs post-scanning and benefit from enhanced ADIF import functionality. Version 5.4 introduced accelerated county searches via FCC databases, with filters for QSL confirmations and e-QSL enhancements. The software also includes a feature for backing up and restoring QSOs by LoTW confirmations. Visual County tools have been refined, offering improved map interactions and the addition of county flags. The software supports various digital modes including FT8, FT4, and SSTV, and includes functionality for PSK250 and 60m bands. The application is multilingual, with support for Italian, English, French, and Spanish, and provides automated updates and web-based county searches. DXZone Focus: County Hunting | ADIF | Windows | LoTW

Sleeve baluns are normally used at VHF and higher. As a general rule, they are not practical at HF. The balun can be inverted and used as a skirt to form part of the antenna element

The RasHAWK team has used a Raspberry Pi as the basis for a networked RF sensor capable of supporting spectrum monitoring, signal intercept and direction finding (DF) operations.

RS41 Tracker is a software running on Windows that it is able to decode telemetries generated by Vaisala RS41 radiosondes. Used with a FM radio receiver it allows to display radiosonde positions on a map.

A simple to build full length 20/40 dipole antenna to be used in inverted vee configuration

Interesting article by WY3A explaining benefits of operating CW

Protecting amateur radio equipment from transient overvoltages requires robust lightning and surge protection, which is the focus of Electronic Specialty Products. The company provides various devices, including coaxial lightning arrestors for antenna feedlines and surge protectors for AC power lines and data circuits. These devices are engineered to divert high-energy surges, such as those caused by direct or indirect lightning strikes, away from sensitive transceivers, amplifiers, and computer components, thereby preventing catastrophic damage. Key products include the _Coaxial Lightning Protector_ series, designed for various impedance levels and frequency ranges up to 3 GHz, and the _AC Line Surge Protector_ for shack power distribution. Effective deployment of these protection devices can significantly reduce the risk of equipment failure and ensure operational continuity during severe weather. For instance, a properly installed coaxial arrestor can handle peak currents of **20 kA**, while AC line protectors offer clamping voltages typically below 400V. Comparing different models reveals varying levels of insertion loss and return loss, with some coaxial units exhibiting less than 0.1 dB loss at 500 MHz, making them suitable for high-performance HF and VHF/UHF operations. Integrating these components into a comprehensive grounding system is crucial for achieving maximum protection against both common-mode and differential-mode surges.

List of scanner frequencies used in the US for emergency or inter-agency communications, allocated nationally.

Demonstrates the operational status and reception reports for the SK6RUD/SA6RR QRPP beacons, which transmit on 478.9 kHz, 1995 kHz, 10.131 MHz, and 40.673 MHz. These beacons utilize extremely low power, with the 630-meter beacon operating at approximately 0.1 watt ERP into an L-antenna, showcasing the potential for long-distance contacts under favorable propagation conditions. The site details the specific frequencies and antenna types employed, such as a vertical at 500 kHz and a 1/4 vertical for higher bands. The resource compiles over 10,530 reception reports from amateur radio operators worldwide, logging details such as date, time, band, RST signal report, locator, distance, and receiver setup. Notable long-distance reports include a 500 kHz reception by AA1A-Dave from 5832 km in 2008 and a 10.133 MHz reception by ZL2FT-Jason from 17680 km in 2010, illustrating the global reach of these low-power transmissions. Each log entry provides specific equipment used by the reporting station, including transceivers like the Yaesu FT817, ICOM IC-7300, and various antenna configurations such as coaxial mag loops, inverted Ls, and end-fed wires. The primary objective of the SK6RUD beacons is to challenge conventional notions of power requirements for effective two-way communication, proving that contacts over significant distances are achievable with minimal output. The site also includes a submission form for new reception reports, fostering community engagement and continuous data collection on propagation phenomena across different bands. The detailed logs offer practical insights into real-world propagation characteristics and the efficacy of QRPP operations.

The TMB-1 is an RF amplifier unit / receiving accessory that can be used with a low-impedance broadband loop, a high-impedance terminated loop (such as a Pennant, Flag, or Kaz Delta), and whip (telescoping rod) antennas.

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

PetitTrack is a satellite tracker for the Sharp Zaurus SL-5x00 Linux PDAs. PetitTrack is based on the keplerian propagator algorithm used in kd2bd's Predict software.

Showcasing a range of precision-engineered Morse code paddles, UR5CDX emphasizes craftsmanship in both dual and single paddle designs. Each key, such as the _Eridan MX_ or _CT 73 MB_, is engineered for optimal performance, catering specifically to the needs of CW operators. The paddles are not merely tools; they reflect the artistry inherent in ham radio equipment, with options for personalization like _Callsign engraving_ and _3D nameplate_ tags. The commitment to quality is evident in the materials used and the precision of the mechanics, ensuring reliable operation during contests or casual QSOs. Yury, UR5CDX, also engages with the community, sharing insights on the manufacturing process and the impact of current events on production timelines, fostering camaraderie among operators who appreciate the nuances of Morse code communication.

This resource, originally intended to detail the technical specifications of the **Clover** digital communications mode, currently presents a "Page not found" error. The _Clover_ mode was designed for conveying 8-bit digital data over narrow-band high-frequency radio channels, offering robust performance under challenging propagation conditions. Its design focused on efficient data transfer and error correction, making it suitable for amateur radio operators seeking reliable digital links. The absence of the page prevents analysis of specific technical parameters, such as modulation schemes, data rates, or error correction codes that would have been presented. Historically, Clover offered significant advantages in throughput and reliability compared to earlier digital modes over HF, often achieving higher effective data rates than modes like PACTOR or AMTOR under similar signal-to-noise ratios. Without the content, a direct comparison of its performance metrics or practical application scenarios is not possible.

An effective multiband HF Vertical antenna, used as remote station antenna. Pictures and review of this vertical HF antenna by VK5SW

Virtual Serial Ports Emulator for Windows. Virtual Serial Ports Emulator tool (and VSPE API) is free on 32 bit platform and can be used with no charge for any purpose. No registration or activation key is required.

This almost trivial circuit may be used to charge a pair of AA or AAA sized rechargeable battery cells from sunlight.

Used test equipment, used electronic test equipment, refurbished test equipment and other pre-owned electronic test and measurement equipment to buy or rent.

Tips on winding wire coils used as inductive loads, traps, band-pass filters, are implemented in a number of amateur radio projects especially antenna projects

Improving measurement accuracy when low-power analyzers are used.

This is another alternative home-brew center connector for a dipole. The parts used are common PVC accesories found at the home supply store.

For radio amateurs seeking to identify or verify callsigns from Bosnia and Herzegovina, an online callbook service offers a direct search utility. This resource focuses exclusively on the _T9_ prefix, allowing users to input a specific callsign and query a dedicated database. It serves as a historical reference for contacts made prior to its last update. The utility provides a straightforward interface for callsign lookups, presenting results based on data compiled up to _July 31, 2000_. While the information is static and not current, it remains useful for confirming older contacts or for historical research within the amateur radio community. The service is maintained by _Boris Knezovic, T93Y_, offering a focused resource for this specific geographic region.

The Pecker is a software application that emulates an existing hardware amplifier tuning aid operated in SSB mode as apposed to CW or AM. As such no carrier is used by G7EIX

Discussion at eham about wire size used in wire antennas, and how it affects the gain of the antenna