Search results

An homemade portable vertical antenna with a trap near the mid point of the main element. The trap is made with 42mm diameter PVC pipe with 9 turns of wire on it

A vertical antenna for the top band, made with a 26m fiberglass spiderpole by DJ0IP

An homebrewed dipole antenna for 14MHz

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.

Fiberglass and bamboo poles poles, pole mounts

Building coils for a portable dipole using a novel method of winding coils with weedeater cord! By K4MMG

The idea of using a low mount dipole, enhanced with reflector wires directly beneath the dipole, on the ground, appears to be a very good approach to creating an NVI specific antenna for local HF operation.

German article on the multiband dipole by DG0KW. This antenna can be configured for several bands and can work in 3 or 4 bands mode. Can be used in restricted space lots.

JJ0DRC's HF multi-band delta loop antenna project, initially conceived during the waning peak of Cycle 23, addresses the common challenge of achieving effective DX operation from a small residential lot in Japan. Dissatisfied with a ground plane antenna's performance in SSB pile-ups, the author sought a beam-like solution without a tower, drawing inspiration from a JJ1VKL article in CQ Ham Radio Sep. 2000. The antenna, constructed in October 2000, employs two 7.2-meter fishing rods (37% carbon fiber, reinforced with cyano-acrylate glue and aluminum tape) and 1mm enameled wire, fed by an Icom AH-4 external antenna tuner. While the exact beam pattern remains unmeasured, JJ0DRC observed a significantly higher callback rate compared to dipole antennas, particularly on higher bands. The system's circumference length of 15-20m is crucial for maintaining a good beam pattern across HF bands, though performance on lower bands like 80m, 40m, and 30m becomes less directional as the length deviates from a full wavelength. Ongoing maintenance addressed degradation issues, including aluminum tape cracking and wire breakage at connection points due to strong winds (often exceeding 10-15m/s in winter). The author reinforced rod connections with IRECTOR PIPE SYSTEM components and INSU-ROCK ties, and improved wire attachment methods using Cremona rope and epoxy bond to enhance durability.

Design your owm HF shiortened dipole. Includes a diagram of a lumped-constant loaded dipole antenna that is intended to fit in available space, rather than requiring a full 1/2 wavelength, at a specified frequency

This doubet antenna is a half wave dipole antenna easy to build, in french

This resource details the computer-optimized design of the _ZS6BKW_ multiband dipole, an evolution of the classic _G5RV_ antenna. It begins by referencing the original 1958 RSGB Bulletin article by Louis Varney G5RV, explaining the operational principles of the G5RV's flat-top and open-wire feedline on 20m and 40m, noting its impedance transformation characteristics for valve amplifiers of that era. The article then transitions to the rationale for optimizing the design for contemporary solid-state transceivers requiring a 50 Ohm match. The core of the project involves using computer modeling to determine optimal lengths for the flat-top and matching section, aiming for a VSWR of less than 2:1 on multiple HF bands. It discusses the process of calculating feedpoint impedance based on antenna length and frequency, referencing professional literature from Professor R.W.P. King at Harvard University. The analysis also considers the characteristic impedance (Z(O)) of the open-wire line, identifying a broad peak of adequate values between 275 and 400 Ohms. Specific design parameters for the improved ZS6BKW are presented, including a shorter flat-top and a longer matching section compared to the original G5RV, with a velocity factor of 0.85 for the 300 Ohm tape. The article confirms acceptable matches on 7, 14, 18, 24, and 28 MHz bands when erected horizontally at 13m, and also discusses performance in an inverted-V configuration, noting frequency shifts. The author, Brian Austin ZS6BKW, emphasizes the antenna's suitability for modern 50 Ohm coaxial cable without a balun.

The I0JXX is an italian company that offers market their projects, also sells electronic products of high quality, both for Ham, both Broadcast and their accessories. VHF Antennas, mosfet power amplifiers, filters, insulators, power dividers, telescopic poles, antenna masts

The Fan dipole antenna offer a easy to setup and efficient HF multiband antenna that does not require tuners or antenna switches, diagram by YC8PVU.

A 40 80 dipole antenna design by WA6ESC PDF File

Ham Radio 20 / 40 meter short Coax Trap dipole antenna designed with the coax trap design calculator program

Build yourself a postage stamp 40 meter wire dipole antenna that fits in a space a little over 20 wide and works reasonably well at low heights

An analysis of the cebik dipole and other small limited space dipoles fed with open wire ladder line.

J-Pole Antenna by K4TAX

An inverted V antenna for 40-80 with loading coils. This antenna is a full size on 40 and a shortened 80 by KG0ZZ.

A shortened dipole for 40 meters band by Martin E. Meserve

A multi-band inverted-V dipole for portable operation by GM3VLB

Located in France, DXBeam designs and manufactures a range of monoband, dual band and triband antennas, rotary dipoles, Moxons and Yagis

This article explores a theoretical model for the losses of an 80m / 40m trapped inverted V dipole antenna system using a bootstrap coax trap, but does not examine the pattern of the antenna.

A simple, cheap, efficient tv antenna that you can make yourself.

Pictures of a 2 meter, 220, 440 copper J-Pole antennas

Put up the longest dipole you can fit, feed it with open wire line, connect it to the balanced output of your tuner and poof! Instant multiband antenna. Is life really that simple?

Hints about Jpole Yagi and Quad antennas

A multiband 20/40/75/160 trap dipole antenna plan by KG0WX

This is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It is a dipole fed off center with a 4:1 current balun at the offset feedpoint. The antenna shown covers 80, 40, 20 and 10 meters with 15 meters and WARC bands

A three-frequency multi-band dipole that can be extended easily to additional bands. This article includes a multiband fan-dipole antenna for 80-40-20-10 meter band.

An easy to build single wire antenna for 160 and 80 meters with a better than 2 to 1 swr across the 80 meter band

Online calculator and construction instructions

D3+ High Performance Antennas for Field Day. This article describes versatile broadband wire antennas. These antennas will double your effective radiated power over a dipole, will be easy and inexpensive to build and install, and will be simple to match.

Antenna manufacturer from Poland, produce dipole wire antennas, W3DZZ FD4 Windom and long wires, baluns, dealer for toroids and connectors managed by Leszek Mlynarczyk SP1BKS

A W3DZZ trapped dipole for 80 40 and 20 meters band by ZL1BJQ

M0VEY shares insights into constructing a 160-meter mobile DX aerial, detailing the process of sourcing materials and assembly. The project began with a goal to avoid a £50 commercial antenna, instead utilizing a £10 reel of _enamelled copper wire_ and salvaged components like alloy tent poles and plastic water pipe. A friend fabricated a custom stainless steel tube for mounting, featuring a 3/8” thread for a mag-mount, enabling secure vehicle attachment. The aerial's design incorporates four alloy tubes, one plastic tube, and a five-foot whip, engineered to split into two pieces for convenient storage. The loading coil, wound with approximately 115 feet of 0.75mm wire onto a plastic former, was then sealed with blue heat shrink. M0VEY reports successful operation, making contacts across the UK and Europe, with the aerial standing about ten feet tall for local nets at 1.972 MHz and taller for the DX window around 1.845 MHz. Future plans include a base-loaded 160m aerial and an 80m version, leveraging components from the existing _160m DX Mobile Aerial_ to maintain a similar overall size with a smaller coil.

The ZS6BKW wire antenna, a variant of the G5RV, utilizes a specific 13m (42.6 ft) length of 450-ohm window line as its matching section, feeding a 28.5m (93.5 ft) flat-top element. This design aims for lower SWR on 40m, 20m, 17m, 12m, and 10m compared to a standard G5RV, often achieving SWR values below 1.5:1 on these bands without an antenna tuner. The feedpoint impedance transformation provided by the window line allows for direct connection to 50-ohm coax on multiple bands. F4FHH's experience involved constructing the ZS6BKW and evaluating its performance against an _OCF dipole_ (Off-Center Fed) on various HF frequencies. The article includes observations on SWR readings and operational effectiveness, highlighting the ZS6BKW's suitability for multi-band operation. The antenna's overall length, including the flat-top and window line, is approximately **41.5 meters** (136 feet), making it a significant wire antenna for fixed station use. Comparative analysis with the OCF dipole provided practical insights into the ZS6BKW's advantages and limitations, particularly concerning bandwidth and tuner requirements.

A french document about Inverted V dipole antennas

This article describes the design of an antenna for local contacts on 7MHz, including a simple and efficient matching system that presents a 50 ohm load to the transceiver.

An home made trapped dipole antenna for 40 and 60 meters band by 2E0HTS

A shortened 7 MHz Dipole antenna as described by Ken GM4JMU in Sprat 74.

The simple dipole is perhaps the best antenna for consistent performance. Basic page on dipoles by G3PTO

Details the construction of a **17-meter Moxon Rectangle** antenna, specifically engineered for mounting on a mast beneath an existing beam. The design incorporates insulated wire calculations (0.95804 x generator length) to compensate for velocity factor differences, utilizing readily available materials such as crappie poles for elements, PVC for the boom and mast, and a Budwig HQ-1 dipole connector for the 50 Ohm coax feed. The project outlines a step-by-step assembly process, including mast construction from PVC T-connectors and pipe, element fabrication from crappie poles, and securing elements to prevent droop. Initial testing demonstrated an SWR of 1.3:1 on 17 meters, achieving a 5-8 signal report into Texas with 100 watts. Subsequent reinforcement and elevation of the antenna resulted in a 15 over 9 report from Florida. Comparative testing against an 88-foot center-fed Zepp antenna indicated superior performance, with the Moxon consistently outperforming the Zepp and receiving signals the Zepp could not. A notable DX contact with JA8NFV in Hokkaido, Japan, yielded a 5-9+ signal report both ways using 100 watts.

An easy to build multiband trapped dipole that can work well on short low bands for skip contacts

Homebrew project of a dipole for six meters band by KK5ID

A telescopic pole that you adjust to suit the band you're working on , tested on 40 20 and 15 meters band by M0PZT

Multiband and monoband HF Vertical antennas and rotatable dipoles manufacturer based in Texas USA

A simple beam antenna offering good performances on 3 bands by 9m2mso

The half wave dipole antenna is a simple and practical antenna model that consists of a half wavelength long centre fed conductor.