Search results

An Attic Coaxial-Cable trap dipole for 10, 15, 20, 30, 40, and 80 meters

PDF article about a coaxial 1:1 balun, original concept by I4BBE using a quarter-wavelength and the three-quarter-wave adapting sections with the 50-Ohm coaxial cable by I0QM

This is a deviation from the wonderful antenna the Double Bazooka. The Vertical Bazooka, is made entirely from RG-8U coaxial cable.

This is a vertical multiband antenna made up of several aerial elements lambda/4 length, feeded with just a coaxial cable in French.

A very beginner's guide to coax cables. Characteristics, detailed comparison of typical coaxial cables, commonly used connectors, and a few words about SWR.

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.

This article describes how to make a quadrifilar helix (QFH) antenna easily, from inexpensive materials: uPVC plumbing pipe and RG-58U co-axial cable. A low-cost, easy-to-build Quadrifilar Helix (QFH) antenna for weather satellite reception using uPVC plumbing pipe and RG-58U coaxial cable. Unlike traditional designs requiring copper pipe and plumbing skills, this approach enables construction with basic tools and minimal technical expertise. The antenna's shorter, wider proportions favor higher elevation angles, reducing interference from horizon-level pager transmitters. Electrical connections are simplified at the antenna's apex, with the coaxial cable forming the radiating elements. Testing demonstrated consistent signal strength throughout satellite passes, proving effective weather satellite reception is achievable without precision engineering to sub-millimeter tolerances.

Here is a very simple 70cms dipole from Harald PD2HFE, which uses a single piece of RG-213 coaxial cable 34 cms in length.

Show diagrams, winding methods and tables of some 1:1 and 4:1 baluns for 1.8 - 30 MHz suitable for use up to 200W (400W peak) on systems using 50 or 75 ohm coaxial cable input where SWR should not exceed 1.6:1.

This page describes the design and construction materials W8WWV used to build a coaxial cable trap. A coaxial cable trap is a parallel resonant circuit that is usually inserted in an antenna element to enable multiband operation.

Notes on making the W2DU choke balun by placing several ferrite sleeves around a coaxial cable.

Coaxial Cable Dipole for 30 meters band by I2NDT with detailed pictures of his dipole antenna setup.

This multiband antenna 10-80 meters is a home made project by I1BAY. Has been used for SOTA activations with great results. Traps are done with coax cable turns, dimensions are in the attached schema.

This improved multiband trap dipole introduces a new trap design and a change in trap location. The antenna features double-coaxial-cable-wound traps having lower reactance and a higher quality factor (Q) than earlier coax-cable traps by W8NX

This project details three variants of a vertical half-wave antenna design for the 4-meter (70MHz) amateur radio band. The antennas use end-feeding with a parallel-tuned circuit for impedance matching to 50-ohm coaxial cable. The first variant uses suspended flexible wire for portable use, the second employs a fiberglass rod with internal wire for permanent outdoor installation, and the third utilizes aluminum tent poles for quick mobile deployment. Despite the narrow bandwidth of the matching circuit, this suits the narrow 4m FM allocation well. The design offers an effective omnidirectional radiation pattern and can be constructed with readily available materials.

manufactures and distributes HF, VHF, UHF and SHF equipment covering 10MHz. - 47.0GHz. Our products include: Wireless LAN / WAN Bidirectional Linear Amplifiers, Low Noise Preamplifiers - LNA's, RF Linear Amplifiers, Relays, Transverter Systems, Frequency Translation Systems, Downconverters, Antennas, Parabolic Dishes, Coaxial Cable, Relays, Antenna Switches, Microwave Test equipment, PC controlled Receivers, Microwave Linear Amplifiers including models for Telemetry, Wireless, and CDMA applications.

This article describes the construction of a Moxon rectangle antenna for the 70MHz (4-meter) amateur radio band. This compact two-element beam design features folded element ends, reducing its width to approximately 75% of a half-wavelength. The antenna was built using enamelled copper wire stretched over a lightweight fiberglass kite spar frame, with a direct coaxial cable feed connection. Initial testing showed a VSWR of around 1.3 with distinct nulls at 90 degrees when horizontally mounted. The author later tested vertical polarization and suggested that the antenna's compact size might allow for indoor loft installation.

Described here is a simple omni-directional, vertically-polarized dipole for two meters. Made from coaxial cable, it can be rolled up and stored in a small container

Coaxial cable loss in db per 100 ft.

The Bazooka-antenna was developed by the staff of M.I.T. for radar use. The original Bazooka used coaxial cable for the entire radiating elements.

This simple antenna is capable of remarkable results on 160, 80 and 40 metres. Forming a triangle from around 50 feet of satellite TV coaxial cable, the top of the triangle can be as low as 15 feet, and the lower side just high enough to prevent a passer by hanging themselves

A coaxial cable tuneable magnetic loop antenna for 7MHz. This experimental antenna does not require a tuning capacitor

This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

OE1MWW monopole antenna made with common RG 58 or RG 213 coaxial cable

N0KHQ Moxon rectangle for 17 meters, constructed from RG-58 coaxial cable

RF Choke to prevent hf currents on the feedline. This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

The Moxon Rectangle is growing in popularity as a compact 2-element array that approaches a full-size 2-element in gain but with a far superior front-to-back ratio and a direct match for the standard 50-Ohm coaxial cable.

The page describes the construction of a simple omnidirectional, vertically-polarised dipole antenna for two metres using coaxial cable. It can be used indoors or outdoors, with no extravagant gain claims. The project is low-cost and can be completed in about 20 minutes.

This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

A table with Loss in DB/100m , Max power in Watts, Diameter in mm , Velocity factor (VF) expecially in VHF UHF and Microwave

Data and telecom connectors, coaxial cables, smart card connectors and wireless cable products

Coax is a very important part of a satellite station. It is almost as important as the antennas you choose. This article discusses choosing coaxial cables for satellite communication, emphasizing factors like line loss. It compares types such as RG-8, RG-58, Belden 9913/9913F, LMR-400, and hardline, highlighting their impact on signal preservation.

Coaxial cables attenuation chart

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.

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

Based on original G2BCX design this J-Pole antenna for the six meter band is made with a homemade ribbon cable. The antenna shown in this article includes a coaxial cable choke feed to remove RF currents from flowing on the outer of the cable.

A balun is a MUST for dipoles or similar antennas when they are feed with coaxial cables. Many hams connect the center conductor of the coaxial cable to one side of the dipole, and the shield to the other. Wrong!

The document provides a comprehensive overview of baluns, which are devices used to connect balanced loads, like dipole antennas, to unbalanced inputs, such as coaxial cables. It covers various types of baluns, including voltage and current baluns, and their design, construction, and testing. The text discusses the importance of baluns in preventing RF currents on coax shields and their applications in Ham radio setups. It also includes practical advice on selecting and using baluns based on antenna impedance and power ratings, along with detailed performance evaluations and construction tips for different balun configurations.

Calculate power loss depending on coax cable you use

Improper grounding or earthing system can cause several unwanted RF interferences (RFI) to television sets, broadcast receivers, hi-fi sets and telephone sets. In this Article the author explain how to setup a proper radio shack grounding using coaxial cable and ceramic disc capacitor

G3TXQ study on coaxial cable demonstrate that it can reduce an element's length by something approaching the Velocity Factor of the cable

Manufactures and sells coaxial connectors, coaxial adapters, coaxial cables, attenuators, directional couplers, fiber optic connectors, fiber optic adapters, fiber optic cables, coaxial switches, terminators, twinax connectors and cables and tools.

Dodgy plans to make Archimedean spiral antenna for RTLSDR software defined radio receiver. Made of two equal lengths of coaxial cable seems to be the easiest circularly polarized antenna to make that will cover a broad range of the rtlsdr dongles E4000 tuners

5D-FB,8D-FB,10D-FB cables offer very low attenuation comparable to that of famous Andrews' Heliax and 8D-FB is almost half that of standard RG-213 for an equivalent diameter!

A trap on the coaxial cable, also known as choke, helps to eliminate the sneaking of the reflected RF- energy to the shack. The trap can be made from the coaxial cable that feeds the antenna

In this article the author describes some new designs of ferrite loaded chokes for suppressing unwanted common mode currents at HF applied to feed lines like choke baluns, but also in the shack, applied to various coaxial, mains and data cables

Notes on using RG-174 Coaxial Cable at Medium and Lower HF Frequencies by John Bryant and Bill Bowers

A simple coax cable tester built based on the KG0ZZ project.

This web article by VK3BLG details the construction of an experimental 70cm (432 MHz) circularly polarized patch antenna, intended for satellite communication. The resource provides dimensions, feed point specifications, and impedance matching considerations for a single patch element, with discussion extending to array configurations for circular polarization. Construction involves a copper patch element on a dielectric substrate, fed via a coaxial cable. The design is based on information derived from AO-40 satellite antenna specifications, focusing on achieving circular polarization for satellite reception. The article includes specific dimensions for the patch and feed points, along with impedance values. Validation is implied through on-air satellite reception reports, with initial signal reports of **1 S-point above noise** for AO-40 beacons using a grid reflector, improving to **3-4 S-points above noise** with a 2-turn helical feed. The author references a _NanoVNA_ for impedance measurements and discusses the relationship between slot and dipole antennas in the context of patch design. DXZone Focus: Web Article | 70cm Patch Antenna | On-Air Satellite Reception | Circular Polarization