Search results

The DXrobot, operational since 1999, offers a free, non-commercial service primarily for the VHF ham radio community. It specializes in automatic real-time E-skip warnings for **144 MHz** in both Europe and North America, delivered via email or SMS. Additionally, the system provides automatic aurora alerts for _50, 70, and 144 MHz_ openings through the same notification methods. Beyond real-time alerts, the DXrobot facilitates the reception of the latest DX-cluster spots via email, a feature useful for operators without immediate WWW or cluster access. The service also displays recent E-skip and aurora spots detected by the DXrobot on 50, 70, and 144 MHz, with updates every five minutes. Historical data includes lists of all DX spots from the previous day on 50, 70, and 144 MHz, updated daily. Key propagation data, such as MUF timeline, Solar X-rays, Geomagnetic Field, and Estimated Kp index, are also presented.

Also known as Magnetic Loop Antennas, by AA5TB. Excellent article on construction tips and tecniques of a Small Loop antenna

Display solar activity forecast for next 27 days, display A-index, Sunspot Numbers and Flux forecast including graphs for solar activity and geomagnetic forecast. All forecasts are updated daily.

Article about magnetic loops, construction notes and diagrams

The Coke Loop is a Small Magnetic Loop Antenna tuned by a trombone-style variable capacitor made with standard soda cans

The Antenna Rotator Controller is unique in that it senses, displays, and controls to the earth's true magnetic field. The compass sensor, mounted in a waterproof enclosure, is attached to the mast and sends its signal to a microcontroller

A well documented article on a small magnetic loop antenna for the 40 meters band

A small magnetic loop ready for a hand held walk and talk operation by PY1AHD

A page about a Magnetic loop antenna project for the 40 meters band, includes nice pictures and history of construction

Local and DX contacts from tight spaces, it works from 40 to 17 meters

Understanding high-frequency (HF) skywave propagation is crucial for amateur radio operators seeking to optimize long-distance communications. This resource details the fundamental principles of HF radio propagation, including the properties of electromagnetic waves, the characteristics of various HF bands, and distinct propagation modes such as skywave, ground wave, and line-of-sight. It places significant emphasis on the ionosphere's pivotal role in refracting HF waves, explaining how solar activity directly influences ionospheric conditions and, consequently, propagation paths. The resource integrates real-time monitoring capabilities, featuring dynamic charts and data from DX clusters, WSPRnet, and the Reverse Beacon Network, which allow users to track current band activity and propagation conditions globally. It also delves into advanced topics like Near Vertical Incidence Skywave (NVIS) and gray line propagation, providing insights into ionosonde data and various propagation prediction models. The site presents a detailed analysis of solar-terrestrial interactions, geomagnetic indices, and space weather phenomena, illustrating their direct impact on HF communication reliability. Practical tools and applications are highlighted, including real-time QSO planners, online Maximum Usable Frequency (MUF) maps, and alerts for solar flares or geomagnetic storms. The guide systematically breaks down complex concepts into accessible chapters, offering a structured approach to learning about ionospheric regions, diurnal and seasonal effects, and the interpretation of propagation indicators like foF2, MUF, and Lowest Usable Frequency (LUF). This makes it a robust reference for hams aiming to deepen their technical understanding and improve operational effectiveness.

DF9CY Active Magnetic Antenna project

Portable magnetic loop antennas - G4TPH Mag-loop antennas Reviewed in PW and RadCOM, Both QRP and QRO, Portable. The only Magloop on the market that is fully portable

The Crossed Field Antenna (CFA) is one of the applications of Correction of Maxwell's Equations which was used over 150 years ago which was proved these days that the Magnetic Field Source is only the Displacement Current not the Conduction Current . These Corrections was made by an Egyptian Doctor Engineer Fathi Kabbary , who reached the New Correct Theory which shows that the height and efficiency of the antenna doesn't depend on the wavelength

A magnetic loop antenna calculator made with an excel sheet that run also with open office, let you design mag loop antenna dimensions by AA5TB

An invisible magnetic loop antenna mounted under a table by PY1AHD

A QRP 900 grams hydraulic tuned small magnetic loop antenna by PY1AHD Alex.

A magnetic loop made just of wire. Suitable for portable usage and for QRP operations.

Excellent poster representing the electromagnetic spectrum from 31.2 mHz to 6.52 EHz, PDF file poster designed by Anthony Tekatch

Excel spreadsheet that help calculating dimensions of a high efficiency magnetic loop antenna for HF bands. Giving in input the loop perimeter, loop diameter and loop conductor will calculate electric characteristics, bandwidth, and efficiency

This magnetic loop is 78cm diameter, with the smaller Hertz loop for tuning. Feeding is by gamma match.

Antenne Cadre Project by F5NGZ, description by F5TZA in french

This receive only loop covers a frequency range of about 5 MHz to 22 MHz and is built from readily available parts.

This article describes a loop usable from 7 - 21 mHz, using half inch copper tube 3 feet in circumference

A german documento on magnetic loop antennas

An impedance transformer (9:1) to feed a high impedance long wire (~450 ohm), down to a 50 ohm unbalanced coaxial input.

Compact and efficient magnetic loop antenna that cover from 40 to 10 meters project by G8ODE published by RSARS

A figure-8 double loop antenna

Bill Rinker, W6OAV, handcrafted this compact magnetic HF loop from copper and pvc plumbing supplies, a 12 volt motor, and some teflon sheets. He's had great reports with it.

The Coaxman by Clear Signal Products, Inc. features a complete Wireman line of coaxial cable and antenna wire. Antenna wire, baluns, coax connectors, insulators, ladder line, magnet wire, rope.

The Pocket Loop is a small magnetic loop antenna designed for a carry anywhere operation, it disassembles in 33 centimeters pieces that can be carried even on an attach handbag.

March Paddle by K4QU

A 500-watt mobile antenna project details the conversion of an old 10m hamstick into a highly efficient, multiband "bugstick" for HF operation. The core modification involves replacing the original coil with 25 turns of 6 turns-per-inch, 1.5-inch diameter coil stock, fabricated from #14 wire. This design, intended for a 3-magnet mount on a vehicle cab, achieves resonance on multiple bands by shorting out specific turns on the coil, similar to a **bugcatcher** antenna. Measurements taken with an MFJ-259 analyzer on a GMC pickup show 0 turns shorted for 20 meters (14.2 MHz), 10 turns for 17 meters, 16 turns for 15 meters, 19 turns for 12 meters, and 23 turns for 10 meters. The construction emphasizes using UV-resistant tie-wraps and #14 solid wire with crimp lugs for robust RF connections, bypassing the fiberglass rod for current flow. A bonus section details a 40-meter version, utilizing 48 turns of 8 TPI, 2-inch diameter coil stock.

A light and portable magnetic loop antenna with improved bandwidth and performance by HB9MTN

A magnetic loop antenna using a 28\" bicycle rim for six meter band

picture and dimensions of a coax loop antenna centered at 51.490 MHz

RADIOING eEngineer RFI EMI information

A magnetic loop antenna for 7 Mhz by ZL1BJQ

If you have space constraint at your QTH for a HF antenna, you can try contructing this HF magnetic loop antenna for 40-20 meters bands

Although a magnetic loop antenna(aka small loop antenna) is very compact, its efficiency is close to a half-wavelength dipole if carefully built.

Drawing and plan for an HF magnetic loop antenna

Magnetic Loop antenna for broadcasts band reception

This max size magnetic loop antenna for 14 MHz with a totall circumference of 6m is designed to attach to a wall

A magnetic longwire unun with a T130-2 Iron Powder core by M0UKD

A homebrew Magmount for 2m antenna

Comparison of performance between an indoor random wire versus a magnetic loop using psk31

This ia a home built Magnetic loop antenna which was used by G3BGR, indoors on 7,10 and 14Mhz. The basic idea was in Radcom 1986

Detection and recording of Schumann resonances and other electromagnetic phenomena at frequencies below 50 Hz By Hans Michlmayr

VK3YE magnetic loop antenna plan that cover 7 Mhz to 20 Mhz and shortening loop can work on 21 Mhz.

A complete guide to magnetic loop antenna construction, with analysis of multi-turn and single-turn magneti loops, and and insight on choosing the optimal capacitor, or homebrewing your own butterfly capacitor