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Although most Preselectors are designed with an internal T/R relay, theoretically enabling direct insertion between the transceiver and the antenna, there is a problem when running CW, especially when running full QSK. The switching time of the internal relay is too slow to follow full QSK. The best way to avoid this problem altogether is to insert the Preselector directly into the transceiver’s RX antenna line, thus avoiding entirely the need to switch the Preselector in and out.

A personal blog about amateur radio activities, including homebrew, bitx, ubitx, mcHF, JT65, FT8 and more digital communications.

G3KHZ, SM6CVX, G4EDG, DL6KVA + S21ED and S21TV will activate Bhola & St Martins island AS-140 AS-127

Scandinavian Amateur Radio Teleprinter Group

Operating on Airplane scattering. Scattering of radio signals by airplanes. An introduction to operating ariplane scattering, using aircraft to redirect RF that would otherwise be lost in space. Antenna Pointing, Doppler Shift/Digital Modes, using digital modes to operate airscatter.

For my SOTA activities, i recently bought a QRP transceiver QRP SW-3B, which is a three-band QRP CW only for 40/30/20 m. So, i needed an antenna that would allow to use these 3 bands in SOTA portable activity. Already having some experience with the EFHW antenna, i decided to build one for 40/30/20m.

Encrypted messages, fancy technology, spies use them all to communicate, but sometimes the best way to hide is in plain sight. Right now, broadcasting across the airwaves around the world, are automated, anonymous shortwave AM radio stations that most governments won't acknowledge even exist, much less explain

A document that will guide you on Coaxial-Cable trap optimization process to gain on global antenna performance and on increasing effective bandwidth.

The build was an experiment to see if a tube receiver could be stable enough to receive digital shortwave radio broadcasts. The tube acts as both an oscillator and mixer, so the receiver is a type of direct conversion receiver.

Heinrich Hertz was the first to send and receive radio waves.

A web site dedicated to HamNet in New Zealand

DXChrono Desktop presents a comprehensive suite of real-time amateur radio data, including NOAA solar indices, HF band conditions, and a worldwide _F5LEN tropo_ overlay for VHF openings. It integrates live spots from Telnet DX Cluster, PSK Reporter, and Reverse Beacon Network, displaying them on a dynamic 3D globe or 2D flat map. Additional features include aurora and MUF layers, QTH display with optional cities and grid/CQ/ITU layers, and dedicated support for SOTA and POTA activations. The software also offers a Watch List for callsign alerts and Sun/Moon Az/El widgets for satellite and EME operations. The application provides extensive contest and logging context through integration with _N1MM Logger+_ UDP, Cloudlog API, QRZ Logbook, and ADIF file support, allowing recent QSOs to be mapped directly. A Special Event mode is available for club stations, enhancing field day operations. DXChrono Desktop runs on Windows, macOS, Linux, and Raspberry Pi 4/5, requiring a 64-bit OS and at least 4 GB RAM for optimal performance, distinguishing it from simpler HamClock-style appliances.

How to set new squelch values on Baofeng HT Radios by using the CHIRP software. Make sure you save the original configuration before editing squelch levels. Edit at your own risk.

Icom PW-1 1kw Linear Amplifier described by WA0SXV

The K3NG Keyer is an open source Arduino based CW (Morse Code) keyer with a lot of features and flexibility, rivaling commercial keyers which often cost significantly more.

KB0OXD amateur radio blog

Hurricanes Katrina & Rita information from various sources. Compiled by KD5QEL Robin (New Orleans native) near Atlanta, GA. Not for chitchat--only for communications info.

Notes on using a modified R7100 with discrimator tap

The purpose of this blog is to help new hams and promote amateur radio

A cavity backed antenna is a practical slot antenna tipically used in microwave applications

I used a FT 240-43 for much more power, not needed but beter safe than sorry. 150 Watt continious, 300 Watt PEP SSB, 90 Watt Digimodes 10 Mhz, 18 Mhz, 24 Mhz Very easy to build design and a good antenna for people who don't have much space for big towers or long wires This design is from Hans - PE1RNU

Tektronix Frequency Counters pack the functionality of a frequency counter, meter and timer into one instrument.

29 May to 4 June 2010, WFF comprehensive expedition in Kazakhstan-Zhetisu-2010 WFF expedition on national parks and wildlife reserve of Almaty oblast- Zhetisu-2010

But it is only a couple of dB, The Effect Of Insertion Loss On Transmitted Power (dB to percentual loss) Original Information Provided by Neil McKie WA6KLA

Windows log software for the popular RD contest, usually held in Australia in mid August.

Afghanistan 2011 DX Pedition

Covers the WB2JKJ Educom HF Net, which operates on 7.238 MHz and 21.395 MHz. This resource highlights the activities of The Radio Club of Junior High School 22 NYC, Inc., a non-profit organization established in 1980. The club's mission, "Education Thru Communication" (EDUCOM), focuses on integrating amateur radio into schools across the nation as a teaching theme. WB2JKJ, Joe Fairclough, founded and presides over this club, which is recognized as NYC's largest ham radio club. The site also provides access to the "APPLE SLICE NewsletterCurrent Edition" and information on how to support the organization. It includes a scrapbook section and contact details for further engagement. The content was last updated on May 5, 2023, reflecting recent activity.

The document delineates the operational framework for the Auxiliary Communications Service (ACS) and the Amateur Radio Emergency Service (ARES), specifically detailing their integration into the National Incident Management System (NIMS) for emergency communications. It explains NIMS as a standardized, comprehensive national approach to incident management, emphasizing its applicability across all jurisdictional levels and functional disciplines to enhance coordination among responding agencies. The resource highlights that ACS/ARES operates within this NIMS structure for all events, emergencies, and disasters, aligning with federal requirements for emergency preparedness grants. Specific sections address the dual management structures typical in emergency response: an administrative management structure for day-to-day operations and an emergency management structure activated during specific disasters. It illustrates how ARES provides the administrative framework, while the ACS emergency management structure adopts the NIMS/Incident Command System (ICS) model when activated by entities like the Ventura County Office of Emergency Services. The content further breaks down the ARES organizational hierarchy from national ARRL divisions down to local Ventura County districts and areas, identifying roles such as Section Emergency Coordinator (SEC) and District Emergency Coordinator (DEC). Each of the eight Ventura County administrative areas, such as Simi and Thousand Oaks, is shown to have its own Emergency Coordinator and specific communication plans, all coordinated under a broader District Emergency Communications Plan.

Over 500 different types of high-performance electronic cables are manufactured by Alpha Wire, catering to demanding industrial and commercial applications. Their product lines include the robust _XTRA GUARD_ series, designed for harsh environments, and a range of flexible coaxial cables optimized for signal integrity. These cables are critical components in amateur radio shacks, industrial control systems, and data communication networks, ensuring reliable power and signal transmission. The company provides extensive technical resources, including detailed product specifications, application notes, and RoHS certificates, accessible through their online resource center. Hams often utilize their wire and cable products for antenna construction, station wiring, and various DIY projects requiring durable and reliable conductors. Alpha Wire also offers tools like size guides and competitor cross-references, simplifying product selection. They emphasize continuous uptime solutions, reflecting their focus on quality and durability.

FP/KV1J July 2014 DXpedition to Miquelon

Grupo de radio emissao mensageiros da Paz

This morse key and buzzer design only requires parts that one may already have or are easy to find on the web. There is nothing critical except that the contacts must meet when the key is depressed.

This page describes an update to a project for a Power and SWR Meter for ham radio operators. The update includes a more powerful microcontroller, increased sampling rate, and improved display options. It explains how to use the new components and provides detailed instructions for building the updated meter. The page also offers alternative display options and includes the full source code for the firmware. Overall, this update enhances the functionality and performance of the Power and SWR Meter project, making it more versatile and user-friendly for hams looking to measure RF power and SWR in their radio setups.

A review of the Alpha 87-A power amplifier by WD0M

Yamuna Cable Accessories Pvt. Ltd. specializes in the development, manufacturing, and marketing of power cable accessories, including a comprehensive range of cable jointing kits and components. The product line encompasses _Heat Shrink_ and _Cold Shrink_ cable joints, heat shrinkable tubing, pre-moulded slip-on joints, resin pour, and Tapex systems, all designed for applications up to 66 kV. The company highlights its ISO 9001-2015 certification, signifying adherence to international quality management standards in its manufacturing processes. The resource details specific product categories such as end caps, insulation piercing connectors, copper mesh, fireproof coatings, tubing and components, lugs and ferrules, and safety products. It also features specialized items like _Elbow Connectors_ rated for 25 kV-250, 400, and 630 amps, and various types of tinned copper braid used for grounding and electrical shielding. The site provides an overview of their manufacturing capabilities and global presence across 40+ countries. Established in 1973, Yamuna Densons has over four decades of experience in the industry, positioning itself as a significant designer, manufacturer, and supplier of insulators, tabs, and cable jointing systems in India. The company emphasizes its role as a leading exporter of these products, serving both domestic and international clients.

A homemade simple and inexpensive portable antenna support, handy for quick trips to the field and other portable operations

With over 1700 members CARMA is the largest scanner club in the USA. We support all facets of public safety and promote responsible radio monitoring.

This page is devoted to the state of Maryland. It contains links for Trunktracker information and conventional data, along with amateur radio sites

Radio Shack Pro-97 Handheld Scanner Troubleshooting and Support

SARTG RTTY contest new year and WW-RTTY rules and results

A large collection of electronic components symbols in spanis

Time Mapper UHD is a versatile mapping and time visualization program offering multi-satellite viewing with frequency display and unique country-pairs for PskReporter data. It features live feeds from logging programs and can plot ADIF files. Ideal for schools, offices, or amateur radio stations, it provides customizable 4K or HD world clock displays with over 60 map layers, including ham radio zones and natural features. The program supports various time functions and can import logs for detailed analysis. It runs on Windows 10 or 11 and offers a 30-day free trial.

CQ World Wide 160-Meter Contest rules, results records and log official web site.

I wanted to mount an amateur radio antenna on my truck that was more permanent than the magnetic mount on I already had, but I had a few specific design requirements for the project.

TJ2TT log online and QSL request

Personal web site of VE2WPT Nick from Montreal Canada

Experiments on vertical antennas for HF bands.

On the field comparison among C-Pole antenna, an EFHW vertical antenna and an Inverter V dipole antenna. Test is done using two identical WSPRLite beacons that transmit with 200mW on the WSPR frequency and analyzing spotted results.

A windows program to learn Morse code and doing QSO in CW. The training course contains 39 Lessons based on Koch method. It can sends only letters, only numbers, only punctuation

Determining the characteristic impedance (Z) of an unknown coaxial cable, a common challenge for many radio amateurs, can be resolved with a straightforward method. The impedance of a coaxial cable is derived from its inductance and capacitance, and importantly, these values are independent of the cable's length or the operating frequency. This means that measuring a random length of cable, such as 20 meters, provides sufficient data for calculation. The core of this technique involves an LC-meter to obtain the inductance (L) in microHenries (uH) and capacitance (C) in microFarads (uF). The impedance is then calculated using the formula Z = L/C. For instance, a measurement yielding L=1.2uH and C=450pF (0.00045 uF) results in an impedance of 51.6 Ohms, closely matching **RG-58** specifications. Similarly, a TV coaxial cable with L=1.8uH and C=320pF (0.00032 uF) calculates to 75 Ohms. While the accuracy of this method, depending on the LC-meter's tolerance, is approximately 10%, it proves sufficiently precise for practical determination of unknown coaxial cable impedance, as noted by Makis, SV1BSX, who credits Cliff, K7RR, for the formula's dissemination.