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The information in this article has come from many amateur sources, the most notable was from WA6TEY (sk 1985) Ray Frost, who was a pioneer of VHF Quad designs and one of the best Southern California Transmitter Hunters. Ray built hundreds two meter quads in single and paired configurations as well as his famous mobile radio direction finding quad.

A fractional bandwidth of up to 30:1 characterizes spiral antennas, making them highly effective across a very wide frequency range, often from 1 GHz to 30 GHz. The resource details two primary types: the **Log-Periodic Spiral Antenna** and the **Archimedean Spiral Antenna**, defining each with specific polar functions and illustrating their planar configurations. It explains that spiral antennas are typically circularly polarized, with a Half-Power Beamwidth (HPBW) of approximately 70-90 degrees, and a peak radiation direction perpendicular to the spiral plane. The content elaborates on critical design parameters affecting radiation, including the total length (outer radius) for lowest frequency, the flare rate ('a' constant) for optimal radiation versus capacitive behavior, the feed structure (often an infinite balun) for high-frequency operation, and the number of turns (typically 1.5 to 3 turns). It also discusses the theoretical impedance of 188 Ohms for Log-Periodic spirals, derived from Babinet's Principle, noting actual impedances are often 100-150 Ohms. The article presents a simple construction method for an Archimedean spiral, demonstrating VSWR and efficiency measurements. Measurements from a constructed spiral antenna show a VSWR that is fairly constant across the band, albeit with a mismatch loss of about 3 dB. The antenna efficiency remains around -5 dB (31.6%) across its operating range, indicating a decent wideband radiator despite opportunities for optimization.

The design and feeding of driven elements for VHF/UHF Yagi antennas , modeling, observations and some case studies by Graham Daubney F/G8MBI

The Remote Control Antenna Switch consists of two circuit boards. The control unit and the remotely controlled switch

Green that aluminum into something useful right in your own backyard by WB2CQM

A DIY guide to build your own compact multiband HF antenna based on the G3TXQ version using a 1:4 balun. This article includes the full part list and instructions to assembly, including the center plate.

The Gizmotchy high performance horizontal and vertical beam antenna for 2/6/10/11 meter bands

A page by 9A7PJT dedicated to HB9CV yagi antennas includes link to the HB9CV calculator program and some interesting plans

Useful tips for the use of automatic ATUs

This page allows you to calculate in the most accurate way high-Q inductor coils.

Delta 160-meter receiving antenna used at FO0AAA

The AE6AC 17-meter Moxon antenna project details the construction of a wire beam using readily available materials. This design utilizes four 16-foot fiberglass crappie poles for support, joined at the center with 3/4-inch Schedule 40 PVC pipe and "T" slip fittings. Wire segment lengths for 18.135 MHz were calculated using _Moxgen_ software by AC6LA, with specific dimensions provided in feet and inches for precise cutting. Key construction decisions include joining the crappie pole bases into a central hub and attaching the 16-gauge silver-plated copper wire to the pole ends. Dacron cord with a fisherman's knot secures the wire to the pole tips, while small wire loops at the corners maintain antenna shape. Plexiglas pieces serve as insulators for sections "A" and "C." The finished antenna, weighing less than 10 pounds, mounts on a fiberglass windsurfer mast and incorporates a 1:1 current mode ferrite bead balun. Performance measurements with an _MFJ-259B_ show an SWR better than 1.5:1 across the 17m band, with good front-to-back ratio and reported signal strength improvements of 2-4 S-units over vertical dipoles. Initial contacts included VK2AXB, ZF6GS, and KL1M.

Benefits in implementing a remote antenna switching system and a sample remote antenna switch project

An Unorthodox Antenna, originally by W3AWH is considered a multi-band antenna suitable for fixed location use and as an easily deployable portable antenna for events such as Field Days.

Antenna dimension, diagram and simulation of the ZX Antennen ZX 6-6 Yagi for VHF UHF by DF9CY

This calculator is designed to give the horizontal length of a particular dipole including Tees, antenna, or one side of it, for the frequency chosen. Enter the desired frequency and select the desired calculation from the drop box

The N3UJJ multi band cage dipole antenna project thay can fit a small property

This antenna is intended for the 20-meter Band. There are two Voltage Fed Helical Dipoles, made with 2 slinky that fed with phase shift in 90 degree

Measurements for building a full wave loop using wire

An home made slim jim antenna for 2 meters band by VU2TQC

Demonstrates the adaptation and construction of a 7-element DK7ZB Yagi antenna for the 4-meter band (70 MHz), utilizing components from a defunct 2-meter CUE DEE Yagi. The resource details the modifications made to the original DK7ZB design to fit the shorter CUE DEE boom length, specifically adjusting element lengths for 6mm rod elements while reusing existing mounting holes for the reflector and last director. It provides precise element lengths for the reflector, dipole (12mm aluminum tube), and five directors, along with a note on cutting elements for transport. The article includes a 4NEC2 simulation file for performance analysis and an SWR plot, confirming the antenna's electrical characteristics. It also specifies the calculation for the quarter-wavelength matching cable using SAT752F coaxial cable, resulting in a 909mm length. Practical application is shown with the finished antenna in operation at JO20XC, listing several activated Maidenhead squares such as JO56PA and JP40KS, validating its effectiveness for portable 70 MHz operations.

2 Meter Slim Jim Antenna Using 300 Ohm Twinlead

The essentials of the parabolic reflector or dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links.

An efficient monoband end-fed half wave for 10m, 20m or any other HF band

This PDF document details the construction of a **70 MHz** Big Wheel antenna, a horizontally polarized omnidirectional array. The design utilizes three full-wave loops, each approximately **2160 mm** in diameter, arranged in a triangular configuration. The resource provides mechanical dimensions for the antenna elements and a comprehensive bill of materials, specifying component quantities and types, such as M8 stainless steel bolts, 15x15x1.5 mm square aluminum tubing for spacers, and 8 mm aluminum rod for the arcs. The central hub is constructed from two 160x160x8 mm aluminum plates, with four 40 mm long polyamide insulators supporting the radiating elements. The feed system incorporates a 50 mm diameter aluminum pipe for mounting and a matching stub constructed from a 120x20x2 mm aluminum sheet, connected via M8x10 mm bolts. The resource includes a diagram illustrating the mechanical dimensions and assembly points, including the N-connector fixing point and the center conductor attachment. The project was published on May 25, 2011, by Peter OE5MPL and Rudi OE5VRL. DXZone Focus: PDF | 70 MHz Big Wheel | Mechanical Dimensions | **2160 mm** loop diameter

Antennas for restricted lots, apartments and indoor antennas by VK3YE

Antenna designs that K5TR have collected from various sources.

A Home made QRP tuner for 10-40 meters

Understanding Baluns. This article explores some simple antenna system configurations and the effect of key system components, connections and dimensions on feed line common mode current.

Using patch antenna for amateur radio reception of the 13cm band with a sample 2.4 GHz LHCP patch antenna by K3TZ

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

A New Way to build a 1/4 Wave Ground Plane Antenna

The antenna was built to be used for shortwave listening with a Tecsun PL-660 radio receiver. Later it was used with Yaesu VX-6 handheld transceiver and with Yaesu FT-817ND for shortwave listening.

The document titled 'Extending the Range of Your Handheld' by WG7S is a guide on how to extend the range of your handheld VHF UHF transceiver by using an external antenna. It provides information on comparing popular models, selecting the right antenna, and resources for amateur radio antennas.

Building Eggbeater II Omni low Earth orbit satellite Antennas for 70cm by ZR6AIC

Presentation by AC8GY on classic G5RV Antennas and other horizontal dipoles, the popular G5RV, ZS6BKW, dipole fan, Alpha-Delta DX-CC and a trap dipole are modeled in EZNEC and compared.

The RoadTrek design presents some unique challenges to us hams. Here an example of a VHF and HF antenna installation on a VAN

Construction and analysis of a low cost omnidirectional horizontally polarized antenna for 144 MHz, including notes on halo antenna stacking

Antenna dealer, antenna masts, towers, mounts, antenna rotators, steppir and optibeam inrad dealer

A 10 elements quagi antenna for the 900 MHz band

Testing SWR on your antenna and getting the best performance from your investment by L.D. Blake, VE3VDC

A small antenna tuner for 14 MHz

Russian Quad antenna manufacturer

Ferrite rod antenna or aerial, a form of RF antenna that is widely used in RFID and transistor radio applications.

An online javascript calculator for cubical quad antennas, simply input the resonating frequency to calculcate up to a five element quad antenna. This quad antenna calculator let you determine the total length of each element and spacing among elements.

Only 2x 10ft wide, performance similar to full-size dipole, covers whole band with SWR better than 1:1.2.

A homemade 10 element Yagi Beam Antenna for 50 Mhz by Rod Mackintosh, a NBS Yagi on a 13.2 metre boom.

A home made dipole antenna for 10m, 6m, 4m bands made with two sections of 450 and 300 Ohm ladder lines, cut to achieve acceptable SWRs on all bands

Ever need a way to estimate the amount of wire to add to or remove from a center-fed wire dipole antenna to achieve resonance at a desired frequency? This article help to determine correct wire lenght.

An interesting article on loading short vertical monopole antennas, representing six different methods. Base loading, Center Loading, Top Loading, Continuous loading, half and half loading and capacitive top loading.