Search results

Demonstrates the construction of a 144 MHz turnstile antenna, detailing its design for omnidirectional, horizontally polarized VHF operation. The resource outlines the physical dimensions and materials required, including specific lengths for the radiating elements and the use of _RG-58_ coaxial cable for phasing. It covers the assembly process, emphasizing the critical spacing and connection points to achieve the desired radiation pattern and impedance matching for the _2-meter band_. The article presents measured _SWR_ performance across the 144-146 MHz segment, showing a low SWR of 1.2:1 at 144.5 MHz, which is suitable for general VHF use. It compares the turnstile's performance to a 9-element Yagi, noting the turnstile's advantage in providing consistent signal strength from all directions without requiring a rotator. Practical application for local FM simplex and repeater operations is implied, offering a simple yet effective antenna solution for fixed or portable stations.

About longwire antennas, technically to be a true longwire an antenna needs to be at least one wavelength long, but common use of the term by Hams is for any random wire length that is end fed.

A nice loop antenna project for 28 MHz with schematic diagram, construction details and a complete video instruction

A 40 meter NVIS beam antenna by W4NVK

A Unique VHF Antenna with gain over a J-Pole Jose I. Calderon, DU1ANV

A project of a 5 Antennas Relay Switch Box, all Switches & Relays have both contacts wired in parallel to improve reliability of operation, to prevent static build up, when an antenna is not in use the feeder coax is grounded.

Optimizing performances of the end-fed antennas QRP quarterly article

All types of Military Antennas, Law Enforcement Antennas, Mobile Radio Antennas, GPS Antennas, Satellite Antennas, WLAN/Wi-Fi/WiMax Antennas, Cell Phones, TV, HDTV Antennas available and sold

A 915 MHz four bay j-pole antenna plan

17-Element Very High Frequency/Ultra High Frequency Log Period Dipole Array

Deploying robust antenna infrastructure for both fixed and portable operations often requires specialized support structures capable of withstanding environmental stresses while providing optimal radiating element placement. SMC offers a range of solutions, including pneumatic masts and push-up masts, designed to facilitate rapid deployment and reliable long-term support for various antenna types. Their product line encompasses antenna mounts, poles, and complete antenna systems, addressing the critical need for stable and efficient RF communication. The company's offerings extend to HF antennas, including dipoles and _NVIS_ (Near Vertical Incidence Skywave) antennas, which are crucial for short-range regional communications on bands like 80m and 40m. These systems are engineered for durability and performance, ensuring signal integrity across diverse operating conditions. With over **65 years** of experience, SMC has established itself as a global manufacturer in this niche. Their product portfolio also includes antenna support towers, catering to more permanent installations requiring significant height and load capacity for multiple arrays.

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

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

An excellently presented article on the design and construction of a medium wave DX Antenna

A delta loop antenna for the 4 meter band by GW7AAV

Build an effective dipole antenna that needs much less space by adding two loading coils. This online calculator tells you how.

A simple coax dipole antenna for 144 MHz by 9A7PJT

A novel approach to contruction of a gamma match.

Iulian Rosu YO3DAC / VA3IUL wire ham radio antenna panoramic with sample drawings

US Antenna manufacturer offering base and mobile antennas for 2 meter, 1.25 meter and 70 cm Amateur Radio GMRS and MURS Citizens Band Radio VHF and UHF Business Band Radio HF, VHF and UHF Scanning

High Gain Wi-fi Helical Antenna by AB9IL

The resource presents a detailed schematic for constructing a dual-band vertical antenna, specifically designed for operation on the 2-meter and 70-centimeter amateur radio bands. It illustrates the physical layout, critical dimensions, and component placement necessary for successful replication. Key elements such as the radiating elements, phasing sections, and feed point are clearly depicted, providing a visual guide for radio amateurs undertaking a homebrew antenna project. The diagram specifies the lengths for the VHF and UHF sections, indicating how these elements are integrated to achieve dual-band functionality from a single coaxial feedline. It also implies the use of common materials readily available to most experimenters, focusing on simplicity and effectiveness in its design. The visual format of a GIF image ensures direct access to the construction details without requiring extensive textual interpretation. This schematic serves as a practical reference for hams interested in building a compact, efficient vertical antenna for local and regional FM communications, offering a proven design for immediate implementation.

An RSGB article on end-fed wire antennas and the W3EDP alternative.

Optimization tests of the W3EDP multi-band HF wire antenna a popular aerial among QRP enthusiasts because it is light weight and cheap.

A homebrewed antenna for 2m handheld radios by TB1BIG

Helix antenna online calculator with match calculator

The rhombic antenna is often claimed to be an exceptionally good antenna with very high gain. Modelling rhombic antennas

Raising large Yagi antennas can be a challenging project. A trolley system will make the job a lot easier

This antenna is designed to be mounted off the side of a tower. Works on 136-153 Mhz range but also on 70 cm band

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

SWR (standing wave ratio), is a measurement of how efficiently your antenna system will radiate the power available from your radio. In simple terms, your radio would like to radiate all of its power, but can only do so if the other components cooperate

Memorandum on the Beverage Wave Antenna for Reception of Frequencies in the 550 - 1500 Kilocycle Band", FCC Report 9.2.1, by Benjamin Wolf and Adolph Andersen

The G7FEK Multi-Band Nested Marconi Antenna, a small, efficient all-band antenna.

Configurations of the vertical antenna arrays used at 6Y2A

The page provides a project for an helical dipole for the 40 meters band, resonating on 7 MHz, created by PY1ZFK based on a design by DL8VO. It includes detailed instructions on building the antenna.

Constructing the QE19 Antenna Launcher

A switchable Magnetic Transformer for Transmitting for various impedances

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

This is a plan for a 10 elements yagi antenna for 50 mhz

This handy and cheap portable dipole can be folded and backpacked, carried in use, and adjusted to a very wide range of frequencies by KV5R

How to build a slingshot antenna launcher. Slingshot antenna launchers are used to launch a line over a tree branch, so antennas can be suspended from high up trees

Home made WiFi 11dBi, wide band antenna by T. Marshall

The ZS6BKW multiband antenna, an optimized variant of the classic G5RV, features a 102-foot (31.1 m) horizontal span and a 39.1-foot ladder line matching section. This design, derived by G0GSF (formerly ZS6BKW) in the early 1980s using computer programs and _Smith charts_, aims for improved SWR across multiple HF bands compared to its predecessor. Construction details specify Wireman 554 ladder line and #14 AWG THHN copper wire for the radiators, with precise instructions for determining the velocity factor (VF) of the ladder line using an antenna analyzer or dip meter, ensuring accurate physical length for the matching section. The radiator length is electrically 1.35 wavelengths for the 20-meter band, requiring careful trimming during tuning. Field measurements with an _AIM-4170C_ analyzer by KI4PMI and NC4FB demonstrated good SWR curves and bandwidth on 6, 10, 12, 17, 20, and 40 meters. The antenna was deemed unusable on 15 and 30 meters due to very high SWR, but an LDG AT-100PRO autotuner successfully brought 6 and 80 meters into tune. Contacts were made on 80, 40, 20, and 17 meters, including a **17-meter** contact to Spain. EZNEC models for 80-6 meters are provided, along with an AutoEZ model by AC6LA, which predicted good SWR for 80-10 meters. W5DXP's modifications for an all-band HF ZS6BKW are also referenced.

A multi-band portable vertical antenna can be built with relatively ordinary components obtained from the local hardware store, including replaceable loading coils

The antenna is a VHF side is a 2m moxon, tuned on 145.825 MHz. The driven element of the moxon couples to a driven element for a 5 element 70cms Yagi, tuned on 436.5 MHz.

An online J-Pole antenna calculator that need just to input the frequency and calculates in inch size of each element

This modification will allow the use of separate receive and transmit antennas on the Kenwood TS-850S/AT.

Experiments with spiral dipole antennas. Includes two spiral antenna designs for 20 and 40 meters band by KN9B

Inspired by Milan OK7GU, the goal is to build an universal antenna controller - for different types of rotor, different motor, encoder

Italian web site describing a project for a 2 meters home made halo antenna