rf transformer

rf transformer

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• Balun and Transformer Core Selection - Occasionally errors are made regarding core selection. This especially includes baluns, where on occasion some very strange ideas surface.
  [ Hits: 3798 | Votes: 3 | Rating: 6 ]
• RF Balun Transformers - This application note is designed to help the reader understand how balun transformers can be used in today's RF/Microwave communication applications.
  [ Hits: 2141 | Votes: 1 | Rating: 3 ]
• How to Make a Great 9:1 RX Transformer - There are lots of good designs for matching transformers for receiving antennas. Make it yourself it's cheap and easy, and very high performance. This is the design used in the TRX-9 transformers.
  [ Hits: 3144 | Votes: 0 | Rating: 0 ]
• 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 ]

• Beverage transformer notes - In this article, the author discusses the importance of good transformers for Beverages, especially for common-mode isolation. The author recommends #43 ferrite for the transformer, and provides the turns required for different core types. The author also recommends using lower permeability ferrites for better performance at lower frequencies.
  [ Hits: 1319 | Votes: 1 | Rating: 10 ]
• 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 ]
• Reversible RG6 Beverage Antenna - The author describes building a reversible Beverage antenna for low-band receive applications. He details the construction process, challenges faced, and initial performance testing. The antenna uses coaxial cable and transformers for switching direction. Overall, the author is pleased with the results and plans to build additional reversible Beverages.
  [ Hits: 21 | 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 ]

• Outdoor 80m/40m bands Magnetic loop antenna - No matching adjustments needed. Directly perfect match to 50 Ohms using a remotely switched wideband transformer
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• Chokes and Isolation Transformers for Receiving Antennas - Chokes and isolation transformers are essential for receiving antennas to mitigate common mode current, which induces noise and interferes with signal quality. Common mode chokes, formed by winding feedline through ferrite cores, block unwanted current effectively. Proper selection of core material and winding turns ensures resonance near the operating frequency, reducing interference. Isolation transformers further minimize interference, crucial for multi-transmitter stations.
  [ Hits: 59 | Votes: 1 | Rating: 9 ]

• The Classic Beverage Antenna Revisited - This is a QST Article published in January 1982 by W1FB D. Demaw and HH Beverage and is a complete review of the original article published in 1922, which updates and reivew the beverage antenna theory and developlment, explaining the antenna design of transformers and gives accurate reports on antenna general performance.
  [ Hits: 563 | Votes: 1 | Rating: 6 ]

• Performance of 49:1 Ferrite Core Transformers - There are quite a few recipes for building a suitable transformer for an end fed half wave antenna (EFHW), but I was never sure I really understood the main principles. So, I wound a bunch of transformers, made measurements on them using my NanoVNA, learned how to get what I really wanted out of the VNA measurements, and in the process discovered how to build better transformers and be able to predict what they will do
  [ Hits: 151 | Votes: 4 | Rating: 7 ]

• QRP Z-Match Tuner 40-10m - The Z Match is really a basic L Match consisting of a series capcitor and variable shunt inductor, coupled to the antenna using the RF transformer action.
  [ Hits: 1801 | Votes: 0 | Rating: 0 ]

• 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 ]

• CWS Coil Winding Specialist - Manufacturer of transformers, inductors coils and chokes. Custom winding, EMI / RFI Filters, Antenna Windings on ferrite rod, Antenna Winding on phenolic. Any antenna coil designs.
  [ Hits: 593 | Votes: 1 | Rating: 1 ]

• MicroSignals - MicroSignals produces a line of RF and IF signal processing components that offer high performance at an exceptional value. To achieve this MicroSignals began with an engineering team that possessed an excellent background in RF Transformer and Balun design.
  [ Hits: 791 | Votes: 1 | Rating: 7 ]

• SM1000 FreeDV Adaptor - The SM1000 allows you to run FreeDV without a PC. Connect the SM1000 to your SSB radio, and you now have Digital Voice (DV). You don’t have to buy a new radio to run Digital Voice! It’s based on a STM32F4 micro-controller, has a built in microphone, speaker amplifier, speaker, and transformer isolated interfaces to your radio.
  [ Hits: 129 | Votes: 0 | Rating: 0 ]

• PC to RTX interface - Schematics for IC-706, IC-718, IC-756PRO, TS-570, TS-870, and simple universal S.B. interface All three interfaces presented on this page employ galvanic isolation of the transceiver from PC computer. Audio paths are separated by transformers, optocouplers serve to separate the digital paths (PTT and RTTY keying).
  [ Hits: 3784 | Votes: 2 | Rating: 7.5 ]

• WIFI Remote FUCHS ATU for EndFed Antenna - The Fuchs Antenna tuner with a resonant circuit as a coupler. The Fuch Antenna Tuner is providing a high-efficiency compare to a 49:1 transformer using ferrite . The Fuchs tuner is a resonating L/C circuit to step-up the impedance from 50 Ohm to the required 3k. The ATU is able to perform automatic tuning with the addition of a tiny Aduino Nano and a SWR bridge.
  [ Hits: 117 | Votes: 0 | Rating: 0 ]

• Rig to Soundcard Interface by M0UKD - Practival project that contains two isolation transformers, one for AF from the tranciever to the line in on a soundcard, and one from the audio out of the soundcard back to the mic / data input of the radio. Both of which are variable inside the interface via two preset resistors.
  [ Hits: 769 | Votes: 1 | Rating: 2 ]

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