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The AB2RA bowtie 80 meter antenna includes also a 40 meter dipole

Operating magnetic loop antennas requires careful consideration of RF safety, particularly regarding near-field magnetic field intensity. This resource presents calculations for magnetic field strength (H-field) at various distances from a magnetic loop, emphasizing that the H-field is significantly higher than the E-field in the near-field region due to the inductive nature of the radiating element. It provides specific formulas and examples for determining safe operating distances based on power levels and loop dimensions, crucial for compliance with RF exposure limits. The analysis compares calculated H-field values against FCC and ICNIRP maximum permissible exposure (MPE) limits for controlled and uncontrolled environments. It demonstrates that even at QRP power levels (e.g., 5W), the H-field can exceed MPE limits within a few feet of the antenna, necessitating greater separation distances than often assumed for electric field considerations. The practical application of these calculations helps amateur radio operators configure their stations to ensure personnel safety and regulatory compliance when deploying compact, high-Q magnetic loop antennas.

Spipral antenna principle by a concept of Bill Petlowany, K6NO. Tak Antennas are based on this principle, using spirals as dipole linear wires.

iPhone Software to practice taking your Ham Radio Exam

MP3 and Wav files of some stations recorded on HF anc VHF bands by K9MU

Modifications for the Kenwood TS-870S

Constructing a Compact Low Cost Sprinkler Valve Antenna Launcher

A project to homebrew a Lightning Detector

How to repair a FT1000MP front end, damaged from too much neighbouring RF during contesting

Over 45 years of dedicated work by Robert Sherwood, NC0B, culminated in a wealth of technical insights, particularly concerning **receiver performance** and the intricacies of transceiver design. The site provides access to numerous presentations from events like Dayton Contest University and W4DXCC, covering topics such as optimizing rig performance, the evolution of lab testing, and the impact of roofing filters on transmitted IMD and receiver characteristics. These resources offer detailed analyses and practical advice for serious operators and contesters. While product manufacturing, including the SE-3 MK IV synchronous detector and various Drake R-4C accessories like roofing filters and cooling kits, has ceased, the legacy of technical documentation remains. The site details specific products like the Icom IC-781 and R-9000, and offers insights into 455 kHz mechanical and crystal filters, along with DSP protection strategies. Crucially, the site features extensive receiver test data, allowing radio amateurs to compare the performance of various transceivers. This data, often presented in white papers and slide shows, includes detailed measurements and explanations of key performance metrics, serving as a valuable reference for understanding and selecting high-performance HF gear.

CLOVER-2000 is a faster version of CLOVER (about four times faster) that uses eight tone pulses, each of which is 250 Hz wide, spaced at 250-Hz centers, contained within a 2 kHz bandwidth between 500 and 2,500 Hz

Double T Bar Vertical antenna are vertical antenna with cross bars on the top and bottom. These crossbars provide capacitance loading thus reducing the size of the antenna

GAP Titan DX 10 15 20 40 meter performance tests by AA3RL

This antenna article is geared towards new Hams and antenna builders looking for a very inexpensive 6 band antenna that can be efficiently fed with 50 ohm coax without a tune

A simple project for an effective home made band pass filter, designed for the portable field day usage

PACTOR-III is a software upgrade for existing PACTOR-II modems that provides a new data transmission mode for improved speed and robustness. PACTOR-III is not a new modem or hardware device. Most current PACTOR-II modems are upgradeable to use PACTOR-III via a software update since PACTOR-II firmware accommodates the new PACTOR-III software

This resource examines the appropriate use of /M (mobile) and /P (portable) suffixes in amateur radio callsigns, specifically within the context of the UK Amateur Radio Licence. It addresses common ambiguities and challenges in determining operational status, such as operating from a summit or while walking. The discussion references the licence version in force before February 21, 2024, noting that while current regulations recommend but do not specify suffix use, the prior definitions remain relevant for understanding common practice. The content dissects key sections of the licence, including "Notes to the licence" (d)(i-iii) which outlines /A, /P, and /M usage based on location, and "Temporary Location" (jj) which defines /P operations. It also clarifies "Mobile" (17(1)(x)) as operating in or on a vehicle, on a pedestrian, or on a vessel on inland waters. The author provides examples and recommendations for choosing between /M and /P when both might apply, such as when operating from a parked car with a deployed mast or using a handheld on a summit. Historical notes from M1MAJ, G8ADD, and G6MZX are included, tracing the evolution of suffix rules from pre-BR68 days to the 1977 licence version. These historical perspectives highlight how past regulations have influenced current interpretations and persistent myths regarding /M usage. The resource emphasizes making an informed choice based on the licence and communicating the station's operational circumstances clearly.

Alternate means of raising your tower with readily available boat and engine hoists. Examples of working tower hoists with links to manufacturers.

This circuit came out of some work done for two antenna analysers

Quick and Dirty CW Netiquette

Hams have been putting stations in their cars since the Twenties. Today, there is great satisfaction in facing the challenge of installing a transceiver in our small cars and pick-ups, using somewhat inefficient antennas

Codec2 is an open source low bit rate speech codec designed for communications quality speech at 2400 bit/s and below. Applications include low bandwidth HF/VHF digital radio and VOIP trunking.

The fan dipole antenna as an alternative to the paralled dipole antenna, to achieve a larger bandwidth and a better tuning by decreasing elenment influences.A project based on the W6HDG original concept.

This online WebSDR is located near Corinne, Utah, has coverage on all U.S. amateur HF, MF and LF bands, 2 meters, the bottom 1 MHz of 6 meters, and several shortwave broadcast bands.

An RF Field Strenght meter project by the Shefford & District Amateur Radio Society

Here's a tale of early '70s vacuum tubes, mainly from the viewpoint of amateur radio.

An home made HF mobile multiband antenna inspired by the KM4IE HF 20 dollars antenna or the Texas Bugcatcher can work 75 to 15 meters band with an acceptable SWR.

Kingston Amateur Radio Club Articles Dave Lawrence, VA3ORP

A fully equipped amateur radio mobile radio shack by VE6AB

Building the MFJ Cub QRP transceiver kit for 20 meters band by G4ILO

The ATV User's Group is a subgroup of the Auckland VHF Group, Club call ZL1BQ, compromising of persons interested in the transmission and reception of Amateur Television

The project is an AVR ATMega328P based AX-25 1200 AFSK Digital Repeater, suitable for APRS digipeating

How to receive JT-65 signals using a cheap RTL-SDR dongle with the 820T2 tuner chip

In the VLF portion of the spectrum it is easy to listen to the emissions created by the Earth itself. These emissions are generated by many different mechanisms and are often beautiful to listen to. Coverage on LF and MF frequencies

This simple 30m QRSS beacon is built entirely out of junkbox parts, the only component purchased specifically for this project was the 10,140kHz crystal.

A Portable 100 watt radio station setup composed by a 706MKII transceiver, Z-100 antenna tuner and power supply by N1GY

Site dedicated to amateur radio astronomy, providing information on Earth-Moon-Earth (EME) communication, the Search for Extra-Terrestrial Intelligence

Free programming software for the Yaesu VX-7 and VX-7R.

Stop common-mode current when transmitting with an end-fed antenna. Unbalanced antennas are very prone to currents on the outside of the coax.

A home made field strength meter wit detailed pictures and schematic diagram by W4ZT

PropNetPSK is a PSK (Phase Shift Keying) program capable of receiving multiple signals (2 - 16) at one time for the exclusive use to decode a properly formatted PropNetPSK beacon signal. If you are looking for a Keyboard to Keyboard type of program, this will not fit your bill.

ACARS decoder app for the iPad, iPhone, and iPad Touch

The Amateur Radio Association of Bahrain (ARAB) was established in 1970 to support the amateur radio community within Bahrain, operating under the **A92C** callsign. This organization provided a central point for local hams, fostering activities and representing their interests for several decades. Its historical presence is noted, even though it is no longer active. Unfortunately, due to unforeseen circumstances, ARAB ceased its operations. However, a new amateur radio society has since been formed in Bahrain, continuing the tradition of supporting local hams. Interested individuals can contact Fawaz, **A92AA**, for details regarding membership and the new society's activities, ensuring continued amateur radio presence in the region.

Technical specification by Universal Radio

Ionospheric Data Archived at NGDC

Extending frequency to FT-290R for transverter use

Throughput improvement for the FT726R - Tapr PSK modem

A 4 elements Yagi-Uda antenna for 144.3 MHz plan with dimensions and yagimax dimension calculation

Presents the construction of a 2-meter **Skeleton Slot Yagi** stack, detailing the design process and practical considerations for VHF operation. The author shares insights from building and testing this antenna, emphasizing its performance characteristics for local and extended range contacts. The project outlines the specific dimensions and materials used, providing a clear path for other radio amateurs to replicate or adapt the design for their own stations. The resource covers the unique aspects of the Skeleton Slot radiator, explaining how its geometry contributes to gain and pattern control. It includes discussions on impedance matching and feedline considerations crucial for optimizing power transfer and minimizing SWR. The article draws on real-world testing, offering practical results that validate the theoretical design. This project serves as a valuable reference for those interested in custom VHF antenna solutions.