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The page provides detailed information on the G5RV antenna, its feeder arrangement, and efficient operation on HF bands from 3.5 to 28 MHz. It includes dimensions for installation in limited spaces, variations for different bands, and impedance matching details.

Concentric Open Loop Antenna Fed Off-Centre similar to the cobwebb antenna but resonating on 20-17-15-10 meters band

This multiband wire antenna it is an off centre fed dipole, with 10 feet of vertical radiator, needs no tuner on 40m, 20m and 10m and works fine on all bands above 40m with a tuner, and even below 40m on 60m, and 80m.

Multi-band centre-fed antenna capable of very efficient operation on all HF bands, specifically designed with dimensions which allow it to be installed in gardens and other open spaces which accommodate a reasonably-straight run of 31.1m (102 ft) for the flat-top standard model.

All about Spy Numbers Stations, which send coded messages to agents. Includes schedules and frequencies of stations.

Easy to setup dipole antenna for 4 meters band by Tony Hawker G4CJZ

The AZIMUTH program plots a world map in either azimuth (beam heading) or Mercator projections. If you specify your home location in latitude and longitude, the azimuth projection is centred on your location. The Azimuth map program can display Maidenhead grids - this is useful for 6m, 2m, and UHF DX communication display. Various features of the map are: Azimuth or Mercator projections , Maidenhead grid display, Simple map zooming, Print maps with adequate resolution up to one meter sized map

William Hepburn's Daily Tropospheric Ducting Forecast.

The half wave dipole antenna is a simple and practical antenna model that consists of a half wavelength long centre fed conductor.

Connecting centre fed antennas, dipoles, yagis, rhombics, loops to coaxial cable, unless care is taken, it is not difficult to end up with feeder radiation resulting in power loss and the radiation characteristics changes

Centre fed half wave dipoles make great, simple and effective antennas for the HF bands. Sometimes however, the centre feed is not ideal. This great project will improve the overall antenna performance.

An off centre fed dipole, with 10 feet of vertical radiator. It needs no tuner on 40m, 20m and 10m by M0UKD

Navtex Maritime Safety Information Broadcast Channels

Located in the centre of the UK with good grade aluminium,

This antenna can gets you on the air on 14MHz, and it has a useable frequency range. The VSWR is almost perfect at the centre-frequency abd the design uses no expensive components.

Frequencies and location of every meteo radiosonde launching centres in Europe. Equipments, antennas, history, SondeMonitor and BalloonTrack tutorials

The Dilawri Cardiovascular Institute (DCI) is a prominent Canadian organization dedicated to advancing cardiovascular health through cutting-edge research, equitable patient care, and medical innovation. It integrates 16 core centers, including specialized units like the Centre for AI, Data Science, and Imaging, and the Centre for Heart Rhythm, to bridge research findings directly into clinical practice. Their mission emphasizes providing world-class cardiac care accessible to all patients, regardless of their geographic location, by employing disruptive innovation and creative strategies to reach individuals faster. The institute focuses on a team-based approach, ensuring patients receive the correct therapy at the optimal time for long-term well-being. DCI's commitment extends to continuous growth through education, pushing boundaries beyond standard care, and fostering a respectful, inclusive environment for both staff and patients. They lead industry collaborations to shape the detection, treatment, and management of heart disease.

This design has the following advantages low-cost components, Easy to set-up - nothing to adjust, no metalwork required, and only four soldered joints!

The Guernsey Amateur Radio Society (GARS) provides a central hub for amateur radio operators in the Bailiwick of Guernsey, offering resources like a local _GU Callbook_ and specific notes tailored for visiting operators. The society maintains an active presence, holding regular meetings on Friday evenings from 7:30 to 9:00 PM in a unique World War II bunker located within the grounds of the Beau Sejour Leisure Centre. Beyond in-person gatherings, GARS facilitates on-air activity with a 2-meter net operating on 145.525 MHz every Tuesday night at 8:00 PM. Additionally, a DMR net is hosted on Thursday nights at 8:00 PM via the _GB7GY_ repeater, catering to digital mode enthusiasts. These nets provide opportunities for local members and visitors to connect and exchange information. Phil Cooper, GU0SUP, serves as a key contact for the society, managing inquiries and web content. The club's location is precisely described as being down a concrete staircase to the left of the road when approaching the Concourse entrance, making it straightforward for newcomers to find their way to the club's distinctive meeting place.

The Ontario Science Centre Amateur Radio Club (OSCARC) provides volunteer support to the Amateur Radio (ham radio) demonstration station at the Ontario Science Centre in Toronto, Canada.

The club is based in State College, Centre County, Pennsylvania, the geographic center of the Commonwealth, in the middle of the Allegheny Mountains.

A multi-band off centre fed dipole, designed to operate on all bands from 40m (7MHz) to 6m (50MHz). Author claims it will operate on 40, 30, 20, 17, 15, 12 and 10m without an ATU (SWR <3:1) plus 6m with an ATU.

VLF Time Signal Stations, Station List Compiled by William Hepburn, LWCA

Blog post by Adrian M0NWK showing how to calculate the latitude and longitude at the centre of a Maidenhead locator using basic maths.

The areas noted in the forecast have the necessary atmospheric conditions to produce tropospheric bending of VHF, UHF and/or microwave radio waves. Tropospheric bending extends the range of radio & TV stations well beyond their normal limit and thus increases interference amongst stations as well.

These frequencies have been adopted into the bandplans of each IARU region to be a focus for emergency communications in their areas. They are not absolute frequencies but instead are centres of activity and emergency communications may be found around 20kHz from these centres. Some countries may maintain other emergency frequencies in their own bandplans due to local requirements, QRM etc

The _G3TSO_ Mobile Antenna Page details construction and tuning methods for mobile antennas operating across **10 to 160 metres**. The content describes a Hustler-based design, optimized for RF performance and vehicle speeds, featuring centre loading. For optimal operation on various bands, the loading coil placement requires clearance from the vehicle body. Antenna resonance is critical for efficient mobile operation. A mobile antenna's base impedance may be as low as 27 ohms, requiring specific matching to achieve maximum radiation, as a minimum SWR at the transmitter does not always indicate resonance or maximum output. Tuning involves physical adjustment of antenna length to achieve resonance at the operating frequency. The _G3TSO_ page outlines a tuning procedure utilizing a low-power signal source and a field strength meter to identify maximum radiation before impedance matching. Loading coil placement, either at the base, center, or top of the antenna, influences radiation efficiency and mechanical stability for mobile installations. Centre-loaded whips, such as the Hustler design, offer a compromise between efficiency and stability, often for single-band operation. Helically wound antennas, including those for **28 MHz**, may present base impedances around 17 ohms, resulting in a 3:1 SWR at resonance. Low resistance grounding at the antenna base is also specified for optimizing performance and minimizing RFI during mobile operation. DXZone Focus: Mobile | Any | Antenna Tuning | HF

Originally designed by John Kraus, W8JK in about 1940, this antenna has some interesting properties. The W8JK antenna is 2 (Two) centre-fed double-dipole fed by a pair of anti-phase signals. Small size, simple antenna, offer nice performance but need a tuner. Tested in this project from 30m to 6m bands

Learn how to construct a balanced Antenna Tuning Unit (ATU) for your ham radio equipment. Follow the instructions provided by Bengt, SM6APQ, to create a variable capacitor insulated from the ground for additional safety. Discover how to set up the ATU for the 20 to 10m band with proper spacing between coils. Use low power when adjusting the ATU for lowest SWR. Avoid using switches and opt for banana plugs for flexible connections. Visit the Creative Science Centre website for more information and resources on ATU construction.

The resource details HF time broadcast stations, categorizing them into "Standard Frequency & Time Signal Broadcast" and "Time Signal Broadcast" types. Standard Frequency & Time Signal Broadcasts, like those on **2.5 MHz** and **5 MHz**, originate from official time observatories and offer continuous standard frequencies, time signals, and often voice announcements, potentially including meteorological data. These stations operate in the SW band. Time Signal Broadcasts also provide continuous time signals, typically with voice announcements, but without the strict observatory origin requirement. The list includes specific frequencies such as 3.33 MHz, 4.996 MHz, 7.85 MHz, 9.996 MHz, 14.67 MHz, 14.996 MHz, 15.006 MHz, and 20 MHz, alongside the primary standard frequencies. Each entry specifies the station's ID time, call sign, geographic coordinates, and operational notes, including languages like _English_, Chinese, Portuguese, Korean, and Spanish. Some entries also indicate decommissioning dates, such as the station on 3.33 MHz scheduled for 2026-06-22.

TARC meets normally the 3rd Thursday of each month except July and August at the Edithvale Community Centre in North York. All visitors are welcome. See more info on the web site.