bi antennas

bi antennas

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• 80m Inverted-L Base-loaded for 160m - 80m Inverted-L Antenna, Base-loaded for 160m antenna. This antenna is not a good DX antenna however within small garden where true DX antennas would be impossible it has performed very well.
  [ Hits: 123 | Votes: 1 | Rating: 10 ]

• VHF Bi-Square Beam Antenna - 2 Wavelength ,2 Meter Bi-Square Beam , 5dbd gain. This antennas are very cheeap to build and their radiation pattern is similar to a figure 8 with maximum signal through the loop but they may be used as a near-omnidirectional antenna
  [ Hits: 188 | Votes: 2 | Rating: 9 ]
• Two elements Telescopic Yagi for 2 Meters - A lightweight PVC hand-held telescopic 2 element 2m (145 MHz) yagi using two pairs of TV rabbit ear antennas as the driven and reflector elements. Approximate directional gain is 5dB.
  [ Hits: 162 | Votes: 0 | Rating: 0 ]

• Phased Array Antennas - Phased array antennas are composed of multiple individual antenna elements that can have their phase and amplitude controlled to steer the main beam direction in real-time. They are used in radar, communications, and electronic warfare, and offer improved gain and reduced side lobes. A comprehensive document on Phased Arrays include techniques to increase the Antenna Gain and change the Radiation Pattern
  [ Hits: 82 | Votes: 0 | Rating: 0 ]

• Bent-end dipole antennas - Discussion about laterally bent-end dipoles. Bent by percentage of length and fine-tuned by angling the bent ends.
  [ Hits: 123 | Votes: 0 | Rating: 0 ]

• TEFV Terminated End Fed Vee Antenna - The Terminated End Fed Vee Antenna (TEFV) is a travelling wave antenna with constant current distribution. Unlike traditional resonant antennas, TEFV operates without standing waves, using a terminating resistor for broadband efficiency. With a combination of vertical and horizontal polarization, it offers wide bandwidth from 1.8 MHz to 30 MHz, eliminating the need for a tuner. Key components include a 9:1 unun transformer and a 500-ohm terminating resistor. Grounding and counterpoise enhance performance, and it can handle power losses of up to 30%. TEFV provides an effective, versatile antenna solution for amateur radio and broadcast applications.
  [ Hits: 187 | Votes: 2 | Rating: 6.5 ]

• Fan Dipoles 10/15/20m and 12/17/30m - How to build Fan-Dipoles by DK7ZB. Experiences with various band combinations. Not all combinations are working properly. If the frequencies are to close together the impedances will lead to a very bad SWR. This happens with the bands 10-12-15m or 15-17-20m.
  [ Hits: 488 | Votes: 2 | Rating: 9.5 ]

• What is Horn Antenna - Horn Antenna - The energy of the beam when slowly transform into radiation, the losses are reduced and the focussing of the beam improves. A Horn antenna may be considered as a flared out wave guide, by which the directivity is improved and the diffraction is reduced. One of the first horn antennas was constructed in 1897 by Bengali-Indian radio researcher Jagadish Chandra Bose in his pioneering experiments with microwaves. The modern horn antenna was invented independently in 1938 by Wilmer Barrow and G. C. Southworth. This Horn model antenna is suitable employed in the UHF or SHF radio bands. Making this horn model antenna it will be easy for a beginner to make if it works in the 10GHz frequency, because small dimensions so it is not so difficult and also offers gain up to 25dBi.
  [ Hits: 74 | Votes: 0 | Rating: 0 ]

• Improving Gain of the Super J-Pole Antenna - The collinear J-Pole, often known as the Super-J, does improve the behavior over a regular J-Pole. there is an advantage when vertically combining 1/2 radiating sections to have a bit of separation between the half-wave end points. Get 0.8 dB more gain out of the trusty Super-J by replacing the traditional phasing stub with a long coil.
  [ Hits: 192 | Votes: 0 | Rating: 0 ]

• Notes on Designing LF-MF antennas - A free book on designign LF MF antennas. The six chapters in the body of the book are limited to basic information which, combined with a little modeling or simple calculations, can be applied directly using graphs for special problems like inductor design.
  [ Hits: 267 | Votes: 2 | Rating: 9.5 ]
• Transformers for low-bands antennas - Transformers can be used as part of a hybrid combiner or as phase inverters for an RX antenna array.
  [ Hits: 153 | Votes: 2 | Rating: 5.5 ]

• Angle of OCF L-Dipole Antennas - This page is a discussion about impedance matching by Off Center Fed dipoles in the Wide L-form. When a vertical or horizontal dipole is bent into a 90 degree L-form, the impedance drops about half.
  [ Hits: 76 | Votes: 0 | Rating: 0 ]

• K0UO Rhombix Antenna Farm The Ground - Modeling an antenna over real terrain gives you a visual picture of how terrain impacts performance. You can use a model to determine optimum height for antennas on an existing tower, Compare different tower locations for performance, Compare different sites for performance
  [ Hits: 144 | Votes: 1 | Rating: 10 ]

• 2m Slim Jim portable antenna for SOTA - Construct a portable 2m Slim Jim antenna for improved HT signal quality. Utilizing 450 ohm ladder line, the design offers flexibility, durability, and easy deployment. Tuning tips and mounting options enhance its efficiency in handheld transceiver communications
  [ Hits: 67 | Votes: 0 | Rating: 0 ]

• The Yagi Antenna - Presentation - A presentation of the Yagi Antennas, and other interesting tid-bits by Brian Mileshosky. This document explains basic concepts of Yagi-Uda antenna theory, influence of reflector and directors on global antenna gain and directivity of radio waves. A simple tape measure antenna project is also included.
  [ Hits: 543 | Votes: 2 | Rating: 7 ]
• Practical Antenna Modeling with 4NEC2 - Presentation about Practical Antenna Modeling Using the NEC Codes with examples of HF wire antennas and 4NEC2. How to define and edit the models, Running the simulations, Work some examples, Variables usage, Deal with Feed Lines and ground
  [ Hits: 480 | Votes: 0 | Rating: 0 ]

• The Easy Way Antenna Systems - This document is a must read for anyone considering building a good low cost HF multi-band antenna system. The author combine in this document four important ingredients to produce simple but effective antenna system, like antennas of non resonant length, line attenuation, the transmatch and the balun
  [ Hits: 632 | Votes: 2 | Rating: 4.5 ]

• Modifications to the Diamond V2000 and similar antennas - This kind of antenna has grown in popularity over the last years because it gives you a decent performance and triband capabilities. But its 50 MHz design is far from optimal. Here you can learn how to improve its 50 MHz performance in a very easy way.
  [ Hits: 631 | Votes: 2 | Rating: 9.5 ]

• Marine Mobile with Three Antennas - Operating marine mobile with antennas for 15-17-20 meters band.
  [ Hits: 174 | Votes: 0 | Rating: 0 ]

• WiFI vSWR Meter - When building antennas for the Wifi band (Like the 8dBi omni), a need for an easy way to check the antennas arose. A Voltage Standing Wave Ratio (VSWR) meter useable at the 2.4GHz band is however, hard to find.
  [ Hits: 131 | Votes: 2 | Rating: 3.5 ]

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