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An home made antenna switch with a Dummy Load selector. If you forget the radio is connected to the open or grounded side of the switch and you try to transmit, it is very easy to damage the finals of your transceiver.

A loop antenna for 80 and 40 meters band, the main loop is based by a crossed line using aluminium strip lines. The main loop diameter is 150 cm.

Sort of similar to the one of the 6m omni. Instead of using twin-lead, this design makes use of a more or less regular double bazooka antenna (coaxial dipole). Your attention shall be drawn to the available standart literature, such as Rothammel. In order to "compute" the dimension, Karl Rothammel mentioned that the total length of the dipole shall be 95% of the free-space wavelength. The short-circuit bridges (closing the folded dipole) are to be placed at a distance-fraction being equal to the velocity factor of the coax cable used, which will be 66% using RG-58 or RG174.

A modified Hairpin antenna for a wider bandwidth an mounted on a grounded metalic mast

Showcasing innovative RF solutions, Hofi Hochfrequenztechnik manufactures high-quality _antennas_ and RF switches. Their products, including the **versatower** and **fritzel** brands, cater to both casual operators and serious DXers. With a commitment to performance, Hofi's offerings enable operators to achieve optimal signal gain and reliability in various conditions. The company's expertise in antenna design ensures that users can effectively communicate across _HF_ bands, enhancing their overall operating experience. Whether setting up a new station or upgrading existing equipment, Hofi provides essential tools for successful ham radio operations.

You can shorten a vertical antenna by using a loading coil. This online calculator tells you how the amout of inductance your loading coil will need to have.

Founded in 1990, Nearson, Inc. has been providing our customers with exceptional value with the products and services we offer. VHF, UHF mobile radios, Cellular, PCS equipments as well as ISM band wireless data and WLAN applications.

This antenna is an off-center fed spiral dipole for 40 meters. The spiral dipole is very compact, making it well-suited for limited space (like an apartment patio), while the off-center feed gives the antenna some multiband capability.

When a broadcast antenna is to be placed on top of a building, there are special problems of feeding and grounding. The radiator is usually electrically short, that is, much less than one-quarter wavelength high.

The wire antenna described in this page provides much stronger signal strength while staying within the concept of a dummy load antenna.

Useful tips on building cobweb antennas. Since I've done so many posts on the Cobweb antennas I thought it best to separate them on a different page so that potential Cobweb builders can see all the posts together. Hopefully this will make planning and building easier.

Measuring noise fiugre on the W2IMU horn and the dual-dipole-feed

Times Technologies Vector Impedance Analyzer Review

The Magloop Antenna Calculator was developed to predict the characteritics of a small-loop (aka magloop) antenna, given physical dimensions entered via slider widgets. This magnetic loop antenna calculator works also on most mobile devices, adjusting sliders and calculating dimensions in real time.

A home made cobweb antenna project made with easy to find parts 2-14 AWG speaker cables which are cut to 1/2 wavelength for each band and junction box with 4:1 Balun

A home made magnetic loop for HF Bands. This small and compact loop is designed to support small power transmissions on HF bands, from 7 MHz to 21 MHz

An article describing basic concepts of antenna radiation, and in particular directional antennas like Yagi antennas or Quad antennas and how they determine the direction or signals.

Why build antennas out of copper and not aluminum or stainless steel. Selecting the best metals for antennas evaluating the conductivity factor.

A 70 cm yagi antenna design by YU7EF includes tables with antenna elements dimension and spacing. This UHF Yagi antenna plan provides a maximum gain of 17.93 db

Have you measured the SWR at the antenna?

Cubical Quad Antenna On-line Calculator helps on defining the size of each element and spreader. Simply give the resonating frequency and it will calculate size of each element.

The OCFD Off-Center-Fed Dipole Antenna is an excellent multiband antenna that is relatively simple to construct, yet gets quite decent performance.

Over 100 distinct RF connector types are available from AIR802, including popular UHF series PL-259 plugs and SO-239 sockets, designed for a wide array of coaxial cable dimensions. The company specializes in producing connectors compatible with common amateur radio cables like RG-8, RG-213, and RG-58, ensuring reliable signal integrity for antenna systems and shack interconnections. Their product line extends to various coaxial cable types and pre-made antenna cable assemblies, offering ready-to-deploy solutions for hams. AIR802 also provides custom cable assemblies and pigtails, catering to specific installation requirements for transceivers, tuners, and amplifiers. These pre-fabricated options simplify station setup, reducing the need for field termination of connectors. Michael Bryant is the contact for inquiries regarding their range of RF components, which are essential for building robust and efficient amateur radio stations.

An experimental antenna for HF reception. It consists of a single loop element mounted on the ground. It is stealthy, small, and quiet. EZ-NEC plots and on-air test results are included.

This is a standard calculation method that can help you while tuning dipole antennas, by adjusting wire lengths. This method can be used also when you need to add lenght to your wires, and can be additionally used to quarter waves vertical antennas

Constructing an End-Fed Half-Wave (EFHW) antenna offers a practical solution for HF operators seeking a multiband wire antenna without the need for extensive radial systems. This design typically employs a high-impedance transformer at the feed point, matching the antenna's inherent high impedance to a 50-ohm coaxial feedline. The article specifically details a 2012 approach, focusing on a transformer with a 49:1 turns ratio, which is a common configuration for EFHW antennas. The resource outlines the construction of a wire element cut for a half-wavelength on the lowest desired band, with specific coil arrangements enabling operation on harmonically related bands such as 40m, 20m, and 10m. It discusses the physical dimensions and winding details for the matching transformer, often utilizing a ferrite toroid core to achieve the necessary impedance transformation. The content provides insights into the operational principles and practical considerations for deploying such an antenna, including methods for tuning and optimizing performance across multiple amateur radio bands. While acknowledging that the presented information from 2012 may be superseded by newer insights, it serves as a foundational reference for understanding EFHW antenna theory and construction.

Benefits of stacking two HF antennas vertically

_AT Auto_ is an automatic antenna tuner designed for amateur radio enthusiasts seeking efficient and reliable tuning solutions. This device automates the tuning process, allowing operators to focus on communication rather than manual adjustments. The tuner is compatible with a range of transceivers, enhancing its versatility in different shack setups. Its design incorporates advanced circuitry to ensure optimal performance across various bands. The _AT Auto_ tuner is particularly useful for those operating in HF bands, providing seamless transitions between frequencies. Its integration capabilities with other shack automation products make it a valuable component for modern amateur radio stations. The tuner supports multiple modes, including _SSB_ and _CW_, catering to diverse operating preferences. Its robust construction and user-friendly interface contribute to its appeal among both seasoned operators and those new to the hobby. Kessler Engineering's focus on innovation and quality is evident in the _AT Auto_'s design. The tuner is part of a broader product line that includes shack automation solutions, reflecting the company's commitment to enhancing amateur radio operations. Despite the website redesign, the tuner remains a key offering in their product portfolio.

A fand dipole antenna home made for the 7,14,50 MHz. This article descbribes how to homebrew the antenna, hot to setup and some SWR measurements.

This Guide helps you to build the 1:2 BalUn 600 Watts DIY kit step by step. If a delta-loop or quad-loop antenna is powered with a coax cable from the transceiver it is necessary to use a 1:2 BalUn. This 1:2 BalUn uses a symmetrical 1:2 impedance transformer.

An experimento of a 40 meter delta loop antenna both in horizontal and vertical polarization and several elevation angles with interesting notes about the effect of the radial field under the antenna.

Modifying an MFJ-259B Antenna Analyzer to operate on 630 meters

Article descrive the different types including coax and open-wire feeder and waveguide.

Arduino-based Automatic Amateur Radio Antenna Tuner

The video delves into the fascinating science behind antennas, which are crucial for receiving and transmitting electromagnetic waves. It explains how antennas convert electric signals into electromagnetic waves for transmission, and how they operate through the oscillation of positive and negative charges in dipole arrangements. Practical antenna implementations, such as dipole antennas for TV reception and Yagi-Uda antennas with reflectors and directors, are also discussed alongside modern dish TV antennas with parabolic reflectors for signal processing. It's a comprehensive overview of how antennas work and their significance in communication technology.

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.

A comparison of commercial 4m verticals by by Ian Hogan G6TGO

Modified 80cm Offset Dish for 2.4 GHz Satellite Reception. This 50-ohm impedance antenna allows, when connected to 2.4GHz preamplifier and downconverter, to receive Amateur satellites with 2.4GHz transponders such as AO-40.

Maker of small and compact multiband QRP UltraLight Magnetic Loop Antennas and UnUn transformer for end-fed multiband antennas

A simple portable dipole antenna for the 40 meter band using a total lenght of 18 meter. It can be used for 80 to 10 meters coverage using a antenna tuner.

Active Receiving Antennas, designed for reception of shortwave, mediumwave and longwave signals and VHF/UHF signals

This article is about two excellent small helical antennas for the two meters band. With performance close to that of full sized antennas, these small helical antennas are low in profile but high in efficiency.

Active antennas can be very useful, in particular they can help reduce local electrical noise by allowing the antenna to be installed in a corner of the garden well away from house wiring. The original PA0RDT antenna uses a very small patch for the antenna and relies on the antenna being installed quite high.

K2KW notes on verticals antennas

If your antenna is fixed in one direction, you will notice that your antenna works perfectly only during fall and spring.

Available worldwide can be used as Arduino Shield or plug it in to you PC , or with a bluetooth adapter connect to Android. With a highly optimized software, KAI200 brings you: a. Antenna analyzer form 1 up to 200 Mhz; b. WSPR transmiter (set up by serial terminal); c. Square Wave Signal generator KAI200 is all you need for your radio whatever it is Yaesu, Icom, Kenwood or Drake and DIY projects.

Specialist UK manufacturer of high performance compact HF antennas

Quads beams consist of 2 1 wavelength (approximately) loops, ordinarily arranged so that one is the driven element and the other is the reflector. In this project author explains how to build a two element Quad Antenna for the 28 MHz.

TLV80 is model of a Top Loaded Vertical Antenna is doing a good job for DX on 80 m band. A version for 80m-30m is provided.

One of the featured products, the V350 CAMP, is a multiband vertical antenna covering 6 to 80 meters, priced at R$ 799,90, demonstrating the range of ready-to-use solutions available. The inventory includes various antenna types such as **HF**, **VHF**, and **UHF** designs, along with dual-band options like the J-Pole Dual V/UHF for R$ 235,00. For those building their own arrays, the store stocks essential components like element holders, clamps, junction boxes, and aluminum plates, alongside specialized items such as the KIT Isolador Central Dipolo - 01DX for R$ 99,90. The shop also provides a comprehensive selection of installation hardware, including diverse antenna mounts, PTT supports, and various coaxial cables like RG58 and RG213, with prices up to R$ 849,90 for RG213. Connectors such as UHF male PL259 and various adapters are readily available, ensuring compatibility for different setups. Additionally, specialized items like side handles for popular transceivers such as the FT857/891 and IC7300 are offered, catering to specific equipment needs. Beyond antennas, the store supplies practical accessories like transport bags, 12V power cables for transceivers, and even branded merchandise like the Antena Kit mug. Rodrigo Gonçalves, PP5BT, manages the operation from Blumenau, SC, Brazil, providing direct contact via WhatsApp at +55 47 9.9985.0155.