impedance ratio

impedance ratio

Antennas : 15M

• Build a Lightweight 15m Yagi Antenna: Simple Design for Impressive Performance - In this article, Steve G0UIH presents a straightforward guide for constructing a lightweight 15m 3 Element Yagi antenna with impressive performance metrics. With a focus on ease of construction and efficiency, the design boasts a nearly 8.2dbi forward gain and 30db front to back ratio. Utilizing readily available materials and a hairpin match for impedance matching, this Yagi offers broad bandwidth and simple tuning for optimal operation across the 15m band.
  [ Hits: 70 | Votes: 0 | Rating: 0 ]

• Rectangular Loop antenna for 2 meter band - An interesting and easy to build loop antenna for VHF bands, that present a feedpoint impedance of 50 ohms thus avoiding the need for a 1/4 wave impedance transformer. This antenna is ideal for sota and other portable operations
  [ Hits: 279 | Votes: 1 | Rating: 1 ]

• DIY isolation transformers - Article about isolation transformer construction to perform optimal impedance matching. Winding the FCP isolation transformer, includes interesting table for Winding Turns and Lengths and Core Configurations for T300 T200 T400 toroids
  [ Hits: 317 | Votes: 0 | Rating: 0 ]
• Unun vs Balun - Configurations and differences - If you ever asked if you need an Unun or a Balun this article is for you. The right question should be do I need a feed line choke or an impedance transformer whose output is configured as balanced or as unbalanced. An impedance transformer can be configured as a voltage transformer or as a current transformer.
  [ Hits: 345 | Votes: 3 | Rating: 6.67 ]

• A Reversible Beverage at ZL3IX - How do two-wire reversible direction Beverages work, an excellent document that explains fundamentals of beverage antennas. This article details the design and performance of a reversible beverage antenna. Leveraging orthogonality between common mode and differential mode currents on a 2-wire line, this antenna facilitates independent reception from both ends. While common mode signals arrive and are summed on a transformer's secondary for common mode reception, differential mode signals induce anti-phase currents, providing individual reception. Various measurements explore impedance, transmission loss, and F/B ratio, highlighting the antenna's effectiveness and areas for improvement. Notably, increasing the antenna's height significantly improved performance.
  [ Hits: 520 | Votes: 0 | Rating: 0 ]

• Multi-band End-Fed Antenna - An excellent guide to homebrewing multi band end-fed antennas. The article, embed several drawings including diagrams and detailed pictures, illustrating the basic funcionality of end-fed antennas. The author gives some basic hints on how to build a half size antenna for 80 40 to 10 meters and a 6 meter to 40 meter configuration. It is also well described how to build the impedance transformer and the loading coils for lower bands.
  [ Hits: 1105 | Votes: 6 | Rating: 4.5 ]

• End Fed Half Wave Antenna - An easy to deploy antenna, commonly considered the best solution for portable operations. Thir article includes a simple LC parallel circuit to match the impedance by IW7EHC
  [ Hits: 1385 | Votes: 2 | Rating: 1.5 ]
• 40m QRO End Fed Half Wave Antenna Coupler - A medium power End Fed Half Wave Antenna coupler, specifically tuned to the QRP frequency of 7030 kHz. Constructed from coil stock and capacitors, it achieves an impedance ratio of 64:1. The coupler has proven effective for power ranges from 2 to 100 Watts on the 40m band.
  [ Hits: 104 | Votes: 0 | Rating: 0 ]

• SWR: Maximum allowable VSWR - VSWR (voltage-standing-wave-ratio) represents the degree with which an antenna is "matched" to the system impedance. Most modern antennas do not require any tuning for optimum performance. VSWR is one of the easiest parameters to measure and VSWR meters are becoming very popular antenna installation tools
  [ Hits: 1240 | Votes: 3 | Rating: 3.33 ]

• Tuning OCF L-Dipoles - The behavior of a straight dipole and its L-form is examined in terms of impedance and SWR. By adjusting the feed point or bending angle, impedance variation is observed. Impedance shifts symmetrically as the feed point deviates, leading to recommendations for optimal ratios. Model simulations aid in understanding and fine-tuning, crucial for achieving a 50 Ohm match. Practical tuning guidelines ensure efficient antenna performance.
  [ Hits: 29 | Votes: 0 | Rating: 0 ]

• The Basics of Patch Antennas - This article explores the basic concepts of patch antennas. Topics include principles of operation, impedance matching, radiation pattern, circular polarization, bandwidth, efficiency, alternative feed types, stacked patches and higher mode behavior.
  [ Hits: 805 | Votes: 1 | Rating: 9 ]

• Quad or Loop antennas - Quad and loop antennas comparisons, evaluating the impedance and gain of both antennas and considerationso n horizontal loop antennas for low bands by PA0FRI
  [ Hits: 1718 | Votes: 10 | Rating: 4.9 ]

• Matching Waves, VSWR at work - When the radiation resistance (voltage to current ratio) of an antenna is the same value as the characteristic impedance of the transmission line (voltage to current ratio in the line), all of the electrical energy transmitted down the line is taken by the antenna and radiated into space in the form of a radio wave.
  [ Hits: 507 | Votes: 0 | Rating: 0 ]

• Long Wire Antenna for portable operations - With the view to establish a quick and easy multi-band antenna deployment for portable and camping operations a simple long wire antenna with an earth or earth plus counterpoise arrangement with a 9:1 voltage unun including a tuner or simply with a tuner is one possible solution. With the 9:1 voltage unun and wire lengths suggested in the below tables the antenna should present non extreme impedances for all HF amateur band frequencies. This page is far from complete and represents the ongoing investigation into this type of antenna. Experiments to date seem to have raised more questions than obvious answers.
  [ Hits: 804 | Votes: 13 | Rating: 8.69 ]
• The Squid Pole Wire Antenna Re-visited - The author explores enhancing the performance of a 7-meter fiberglass squid pole wire antenna for amateur radio. The wire, resonant at 10MHz, poses impedance challenges on various bands. Experimenting with direct coax feed and UN-UN transformers, the LDG Z11-Pro2 auto-tuner is found effective but may show deceptive SWR readings. The author employs adjustable UN-UN ratios and introduces a custom "porcupine" coil to optimize the antenna's efficiency.
  [ Hits: 91 | Votes: 0 | Rating: 0 ]

• Hittite Microwave Corporation - Amplifiers, filters, attenuators, mixers, PLL, switches and frequency dividers, signal generators, power detectors, transimpedance amplifiers, variable gain amplifiers and more
  [ Hits: 555 | Votes: 0 | Rating: 0 ]

• K0BG's ham radio mobile operator web site - This site is dedicated to mobile amateur radio operators, old and new alike. Whether you are into HF, or VHF operation, I trust the information presented will increase your enjoyment of our great hobby. With safety as a byword, there are articles on amplifiers, antennas, bonding, impedance matching, installing hardware, mobile equipment, noise and RFI abatement, wiring, and much more. I do my best to keep these articles up to date, and easy to follow.
  [ Hits: 4856 | Votes: 10 | Rating: 8.7 ]

• AN-SOF - Professional Antenna Simulation - AN-SOF is a professional comprehensive software tool for the modeling and simulation of antenna systems. AS-SOF allows to describe antenna geometry, Choose construction materials, Describe the environment and ground conditions, Describe the antenna height above ground, Analize radiation pattern and front-to-back ratio, Plot directivity and gain, Analize input impedance and VSWR,Predict antenna bandwidth
  [ Hits: 242 | Votes: 2 | Rating: 10 ]

• VNA calibration kit - A calibration kit useful when you need known reference impedances to properly calibrate your vector network analyzers.
  [ Hits: 301 | Votes: 0 | Rating: 0 ]
• miniVNA PRO Modifications - The mini Radio Solutions miniVNA PRO is the only affordable vector network analyser (VNA) I know of that offers remote wireless operation. This is very interesting because it allows to measure the input impedance of HF antennas installed at height without having to deal with coax cable lengths, baluns nor common mode suppression chokes. However, to render the miniVNA PRO truly field proof, it requires a number of significant modifications.
  [ Hits: 136 | Votes: 5 | Rating: 7.8 ]