transformer

transformer

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• 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 ]

• BalUn for Delta-loop & Quad-loop antennas - This Guide helps you to build the 1:2 BalUn 600 Watts DIY kit step by step. If a delta-loop or quad-loop antenna is powered with a coax cable from the transceiver it is necessary to use a 1:2 BalUn. This 1:2 BalUn uses a symmetrical 1:2 impedance transformer.
  [ Hits: 286 | Votes: 1 | Rating: 9 ]
• 9:1 Unun Impedance Transformer - A 9:1 unbalanced to unbalanced (unun) impedance transformer based on a published design by Peter VK6YSF.
  [ Hits: 195 | Votes: 1 | Rating: 4 ]
• 9:1 Balun and Unun - Homebrew a 9:1 transformer and measurement for testing purposes with a miniVNA
  [ Hits: 109 | Votes: 0 | Rating: 0 ]

• 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: 523 | Votes: 0 | Rating: 0 ]
• Matching transformers for Beverage - Building some proper matching transformer for loop on ground and Beverage antennas
  [ Hits: 76 | Votes: 0 | Rating: 0 ]

• The Pop-Up Vertical 2.0 - Basically, this antenna is a 23-foot wire fed through a 4:1 un-un transformer. This antenna can be easily used in portable operation, for operating all bands from 40-10 meters.
  [ Hits: 254 | Votes: 0 | Rating: 0 ]
• 8010 Enfed Antenna - With this antenna the coverage is 80,40,20,15 and 10 meter band without any antenna tuner and the average SWR is below 1.2 on phone bands. The total antenna lenght is about 23 meters , with one 20.4 meters long segment from the 1:49 transformer to the 110uh coil and about 2.2 meters long segment from the coil to the insulator.
  [ Hits: 142 | 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: 188 | Votes: 2 | Rating: 6.5 ]

• 1:49 unun for end fed half wave antennas - 1:49 UNUN using two stacked FT240-43 cores for end fed halfwave antenna. To match the end fed half wave antenna to the coaxial feeder, it is necessary to have a matching network or transmission line transformer.
  [ Hits: 399 | Votes: 10 | Rating: 8.1 ]
• End-Fed Half-Wave Antenna for 20m 40m 80m - How to Design and Build a Field Expedient End-Fed Half-Wave Antenna for 20m, 40m and 80m. This Shorty 80m EFHW comprises a 49:1 autotransformer (to match the very high impedance at the end of a half-wave wire), a half-wavelength wire for 40m (also a quarter-wavelength for 80m), a loading coil and a short tail wire. The coil and the short tail wire (about 6 feet) make up the other quarter wave on 80m.
  [ Hits: 142 | Votes: 1 | Rating: 4 ]

• The Quarter-wave stub - The Quarter-wave stub can be used for many purposes. If it is left with an open end it can be used as a notch filter to attenuate certain frequencies. A quarter wave length of a transmission line can also be used as an impedance transformer, to know more about the Quarter-wave impedance transformer
  [ Hits: 136 | Votes: 1 | Rating: 8 ]

• 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 ]

• Outdoor 80m/40m bands Magnetic loop antenna - No matching adjustments needed. Directly perfect match to 50 Ohms using a remotely switched wideband transformer
  [ Hits: 225 | Votes: 0 | Rating: 0 ]

• 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: 567 | 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 ]

• 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 ]

• OM0ET Antennas - Maker of small and compact multiband QRP UltraLight Magnetic Loop Antennas and UnUn transformer for end-fed multiband antennas
  [ Hits: 313 | Votes: 7 | Rating: 7.57 ]

• 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 ]

• 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 ]

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