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Constructing a 2.4 GHz high-gain _cantenna_ for wireless networks is detailed, providing a practical approach to extending WiFi range. The author, WB8ERJ, shares insights into building these devices, noting their application in amateur radio for projects like Hinternet or HSMM (High-Speed Multimedia) networks. The article outlines the necessary components and steps, emphasizing the DIY aspect for hams interested in digital modes and local area networking. The resource explains how to determine the correct probe placement within the can, a critical dimension for optimal performance at 2.4 GHz. It references specific measurements, such as the 1.25-inch distance from the can's bottom, derived from calculations for the 2.4 GHz band. This precision ensures the antenna functions effectively for its intended purpose of signal amplification. Readers gain actionable knowledge for fabricating a functional antenna from common materials, suitable for experimentation or practical deployment in a ham shack or field environment. The focus remains on the hands-on construction and the measurable results of improved signal strength.

2-Element parasitic Yagis for the Shortwave-Bands 10-12-15-17-20-30m. The antennas are feeded with the DK7ZB-match. A quarter-wave choke of coax is grounded at the socket.

HF UHF/VHFAntennas, dipoles, accessories and rotators

Online Yaesu FT-817 transceiver (receive only over the Net) using R.A.T.S. control software and MS Netmeeting for program access and audio. Asia's first online receiver, first online FT-817, and worlds first full-featured online receiver (operates just like a desktop radio including audio encoding time of less than 1 second). Operating from a flat in Kowloon, Hong Kong. Open to all.

For radio amateurs considering homebrew antenna projects, this resource details several designs from WE6W, an experienced operator. It covers the construction and characteristics of a _160 Meter QRP Loop Antenna_ optimized for high voltage, along with standard and folded variations of the double bazooka antenna. The site also presents a unique Field Day antenna design and instructions for building a Sterba Curtain, a directional array known for its gain. Each design includes practical insights from the author's building experience. The author provides comparative data, such as the performance of a standard bazooka against a traditional dipole, offering real-world context for antenna selection. The Sterba Curtain section includes notes on its beamwidth and gain, crucial parameters for directional operation. These designs are suitable for hams looking to experiment with cost-effective, high-performance antennas for various bands and operating scenarios, from QRP on 160m to directional DXing with a Sterba Curtain, which can offer significant forward gain, often exceeding **10 dB**.

All these plans use the DK7ZB match

A JavaScript to calculate the dimensions for a seven element Yagi-Uda Antenna

2 meters band HB9CV antenna

RadioRaft decodes 10 different ARQ modes, 8 different FEC modes, Packet, Baudot, CW... It works with a Hamcomm interface or a radiomodem. RadioRaft offers automatic detection of modes, speeds and shift. It comes with a frequencymeter/baudmeter included, it has signal frequency tracking and a bit by bit display mode. Very easy to use. practical and fast.

The HB9CV-Beam is a 2-Element-Yagi with two driven elements and was introduced by Rudolf Baumgartner, HB9CV in the 1950ies. This beam antenna is a coax-feeded version of the ZL-Special construction by DK7ZB for 2m, 6m and 10m

Javascript for calculating the lengths of tubing to be used for the construction of a Super J-Pole in a collinear design

A gamma match example

A switchable antenna for 80/160 meters by IK1ZOY. A new version of a 1/4L 80 m. dipole modified for use in 160 m. band. using it's own coaxial cable feeder to wrap a coil.

Examines the operational differences between **quad** and **Yagi** antenna designs, focusing on their respective performance characteristics for amateur radio applications. The document highlights key metrics such as forward gain, front-to-back ratio, and bandwidth, which are crucial for effective DXing and contesting. It discusses how element configuration, boom length, and material choices impact the efficiency and radiation patterns of each antenna type across various HF bands. Practical considerations for antenna builders are addressed, including structural integrity, wind loading, and overall weight, particularly when using fiberglass spreaders for quads. The resource also covers precipitation static reduction in quads due to their closed-loop design and their ability to operate efficiently at lower elevations compared to Yagis. It provides insights into dual-polarization feed systems for quads, offering independent vertical and horizontal feed points for enhanced operational flexibility.

AirNav Selcal Decoder enables you to decode in realtime Aviation HF Selcal transmissions. It only needs an HF airband receiver and your Sound Card. No special hardware needed. With AirNav Selcal Decoder you do not need any other hardware decoding system. Just your PC and the Sound Card.

Ferrite Toroidal Cores, Magnetic Properties of Ferrite Materials, EMI - RFI Suppression Design Considerations, Ferrite Beads, Ferrites for RFI Ferrite Cores for RFI Suppression by CWS ByteMark

Windows contest logging software with multiple functions like antenna rotor control, dx cluster, cat control, voice and cw keying, supports many data modes, qrz lookup, pirint qsl and labels, mapping and more. Donationware software.

How to build a to 1 balun by N1HFX

Comprehensive listing of all known current HF beacons from IARU Region 1 HF beacon coordinator

Pictures of 2.4 Ghz antennas, JN1GKZ S-band homemade antennas

The _Morgain_ antenna for 40/80 meters is a straightforward and cost-effective wire antenna design, requiring careful tuning for optimal performance across two bands with low SWR. Construction involves creating 12 cm PVC spacers with three holes for wire insertion, along with larger terminals for anchoring and connector housing, which should be sealed with silicone. The provided measurements detail the specific lengths for the antenna elements, crucial for achieving resonance on both 40m and 80m bands. Tuning the Morgain antenna necessitates fabricating four wire segments with pins to temporarily connect and adjust the bridging points symmetrically for both 40m and 80m. This iterative process, though time-consuming, ensures the antenna functions effectively for decades once the precise connection points are soldered and protected. The design emphasizes ease of construction and long-term stability, making it a practical solution for hams seeking a dual-band wire antenna.

The Yaesu VL-1000 Quadra HF Linear amplifier

This rugged antenna, an omnidirectional collinear, is capable of surviving harsh environments. It's a good choice for repeater installations and can be top, or side mounted to the tower by WA6SVT

Even if using a tuner this multiband antenna will let you operate from 160 to 10 meters. If you could only put up one antenna, this would be it. Project by N0KHQ.

Understanding antenna gain is crucial for optimizing an amateur radio station's performance, particularly when evaluating shortened or compromised antenna designs. This resource provides a simplified explanation of antenna gain, focusing on the concept of _capture area_ to demystify the often-complex mathematical formulas found in antenna theory texts. It contrasts full-size dipoles with shortened versions, illustrating how physical length directly impacts an antenna's ability to intercept or radiate RF energy. The article presents practical examples, such as a 20m dipole with **0 dB/d** gain and a shortened 20m antenna exhibiting **-6 dB** less gain due to reduced capture area. It further details the significant efficiency losses in various shortened ground plane antennas for 40m and 160m, showing how a 40m center-loaded ground plane might only radiate **7%** of input power. These comparisons highlight the trade-offs involved in using physically small antennas and underscore the importance of minimizing coil losses for effective operation.

IRAQ War Military HF freqs, Aero HF frequencies and Shortwave Broadcast schedules of interest

This antenna modification is for the IEEE 802.11b networking protocol that operates at 2.4 GHz. It can be scaled easily to the 5 GHz frequency used by IEEE 802.11a by simply scaling the dimensions on the feed can and the excitation antenna to 2.4/5 = 48% of the dimensions shown above.

Many Icom IC-746's suffer from intermittent or non-functioning LCD backlights. Here how it can be solved

NS6T's Azimuthal Map generator provides a web form for creating custom azimuthal projections centered on a user-specified QTH. Users can input their location using latitude/longitude coordinates, a Maidenhead grid square (e.g., IO91um), or a city name, with support for both US and international locations. The system processes these inputs to render a map displaying true bearings from the specified origin. Output customization includes options for distance, with a recommendation for 17500 kilometers and 8.5" x 11" paper size for integration with PSTRotator software. The generated PDF can be zoomed and clipped for use as a .jpg file in PSTRotator/Maps directories. The tool also offers an experimental color azimuthal map variant. City data for non-US locations is sourced from The World Gazetteer. The resource encourages user feedback and problem reports via comments on the associated blog, aiming for continuous improvement of the mapping utility.

Home of the ultimate Ham Radio QSL Label Program! Quick QSL for DOS, featuring great color, dot matrix, laser, and inkjet printer support, a user-friendly interface,

AirLink Express is a user friendly digital mode software package for the Amateur Radio Operator. The software is compatible with Microsoft Windows XP and Microsoft Windows Vista. It offers PSK, MFSK and RTTY digital modes with logging and macro capabilities. If you have ever used the Digipan software you will be immediately familiar with Airlink Express. The user interface is almost identical by Alex Krist, KR1ST

2m SSB/CW-12.5 Ohm Yagis with extrem high gain and small bandwidth. These Yagis were constructed as ultra-light, portable Yagis with extrem high gain. They have small bandwidth and are working from 144,0-144,8MHz with good SWR.

Harv's Hamshack Hack. A remaster of the KNOPPIX distro for Amateur Radio Operators (Hams) who have no prior experience with Linux. Provides a complete OS, software for hobby, web, and word tasks. All contained in an .iso file ready to burn to CD.

SM0DTK's 40-meter Moxon antenna project details the construction and deployment of a wire Moxon rectangle, specifically dimensioned for the 7 MHz band. The resource outlines the use of a _Moxon Rectangle Generator_ for calculating wire lengths and the fabrication of plexiglass supports for corners and the feeding point. It describes the practical challenges of elevating the antenna to approximately **14 meters** using an aluminum tube and fiberglass rod, emphasizing the adjustment process for achieving the correct rectangular shape. The article presents comparative results against a 60-meter long-wire and a full-size 40-meter ground plane antenna. The Moxon demonstrated significant directional gain towards the west, facilitating DX contacts in the Caribbean with **100 watts**, while simultaneously reducing QRM from strong eastern European stations. The SWR was reported as perfect without the need for an antenna tuner, validating the design's effectiveness for targeted signal enhancement and interference mitigation.

a Javascript for calculating the lengths of tubing to be used for the construction of a Super J-Pole.

Maintenance and repair of a Cushcraft R5 vertical antenna

Aviation Radio Service by FCC

Antenna Gain Explained delves into the fundamental principles behind antenna gain, a concept that often perplexes even seasoned RF engineers. The author, Marc, clarifies that antennas do not generate power but rather focus existing RF energy into desired directions, effectively reshaping the radiation pattern. He defines key terms such as _decibel (dB)_, _Antenna Gain_, and _Radiation Pattern_, emphasizing the distinction between dBD (referenced to a ½-wavelength dipole) and dBi (referenced to an imaginary isotropic antenna), noting that dBi figures are 2.14dB higher. The discussion illustrates how a standard ½-wavelength dipole's "doughnut" radiation pattern can be flattened into a "pancake" to achieve gains of 3dB, 6dB, or even 9dB by concentrating energy horizontally. Marc also explains how reflectors and directors are employed in directional antennas to further intensify radiation in a specific direction, potentially achieving gains as high as 20dB, albeit with a narrower effective angle. The concept of _Front-Back Ratio_ is introduced for directional antennas, detailing how some energy inevitably radiates to the rear due to diffraction, even with solid reflectors.

Automatic SWR meter and semi-automatic tuning unit by F1FRV

We specialize in restoring family heirlooms, Grandma's and Grandpa's old radio, Mom and Dad's special set, and the radios you enjoyed as a child!

Description of PSK31, mailing list, frequency for QSO

A small and inexpensive measurement device designed to determine antenna performance across the amateur bands through use of automatically collected SWR readings

2-Element parasitic Yagis for the Shortwave-Bands 10m-30m

Examines the rationale behind L. B. Cebik, W4RNL's, consistent use of dBi for specifying antenna gain in his modeling work, contrasting it with the common practice of using dBd. The article meticulously defines decibels as relative power measurements and introduces the theoretical _isotropic radiator_ as the baseline for dBi, highlighting its utility as an unchanging constant for universal antenna comparison. It details how maximum gain in dBi allows for straightforward numerical comparisons between antennas, while also emphasizing the importance of considering other factors like horizontal beamwidth, vertical beamwidth, and elevation angle of maximum radiation for a complete performance picture. The resource then critically analyzes the concept of dBd, categorizing it into _dBd-I_ (ideal dipole), _dBd-RM_ (real modeled dipole), and _dBd-RR_ (real range dipole), exposing the ambiguities and inconsistencies inherent in these varied definitions. W4RNL argues that the lack of standardized protocols for dBd measurements, particularly in real-world test ranges, makes direct comparisons problematic without extensive supplementary data on test conditions and comparison antennas. He illustrates how these complexities often obscure rather than clarify antenna performance. Ultimately, the article advocates for dBi as the more robust and unambiguous standard for antenna modelers, especially when comparing diverse antenna types where a dipole is not a relevant benchmark. It acknowledges that range testers may continue to use dBd-RR due to practical limitations, but stresses the critical need for detailed test protocols to ensure meaningful results. The discussion underscores the ongoing challenge of correlating real-world antenna measurements with theoretical modeling.

adsbScope is a freeware Windows application designed for processing _ADS-B_ (Automatic Dependent Surveillance-Broadcast) frames received from a compatible decoder. It identifies aircraft, calculates their real-time positions, and presents flight parameters in both alphanumeric tables and a graphical display. The software interfaces via a virtual COM port, receiving raw frames to provide detailed situational awareness, including a global coordinate grid, continental coastlines, over 4,000 **airport** locations, and major cities. Users can overlay OpenStreetMap tiles and view world state boundaries, with each tracked aircraft rendered with labels showing altitude, speed, heading, squawk code, and flight identifiers. When paired with the adsbPIC-decoder, adsbScope enables advanced hardware control, allowing users to toggle data filters for specific frames like DF17/18/19, adjust analog signal thresholds for reception fine-tuning, and manage system resets or bootloader activation directly from the PC. This functionality provides a customizable toolkit for hobbyist radar listeners, offering a robust alternative to commercial tools for processing aircraft data. The software displays up to **1090 MHz** transponder data and can track aircraft up to 250 nautical miles.

A Short Back Fire antenna improved for Wireless-LAN applications

Photographs and QSL of Louis Varney father of G5RV antenna

One common challenge for radio amateurs involves interpreting antenna gain specifications, which are often presented using various units like dBi or dBd. This article clarifies the distinctions between isotropic, dipole, and effective radiated power (ERP) gain measurements, providing a foundational understanding for selecting appropriate antennas. It details how dBi references an isotropic radiator, dBd compares to a half-wave dipole, and ERP integrates transmitter power with antenna gain. Understanding these gain metrics is crucial for accurately assessing an antenna's directional characteristics and overall efficiency in a specific operating environment. The resource explains how to convert between dBi and dBd, noting that 0 dBd equals 2.15 dBi. It also touches upon the practical implications of these values in real-world antenna performance, helping operators make informed decisions about their station's radiating system.

How repair the traps, and then homebrew the rest of the antenna, including the matching box

design by Brian Williams, GW0GHF