at tuner

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Antennas : Delta loop

160m Inverted Delta Loop - This 160 meter Delta Loop antenna is made of Hard drawn copper wire AWG 10, the two upper side are 148.5 foot each base wire is 240.9 foot, the feed point at 30.69 foot to one corner, feed with 450 Homs balanced line to an antenna tuner on the ground, then with 50 homs coax to the shack.
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Antennas : End-Fed

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.
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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 ]

Antennas : Feed Lines : Choke

RF Choke with Bifilar Windings - This article presents an RF Choke featuring an 11-bifilar turn winding of #14 house wire on a Fair-rite FT240-31 toroid. The choke is enclosed in a 3D-printed case from Thingiverse, though this may pose thermal concerns at higher power levels. With SWR concerns up to 30MHz, the author plans to employ two series chokes at the rig input for improved performance. This choke offers versatility for portable use, with potential mismatch resolution using an antenna tuner. Further testing is anticipated upon the arrival of new cables.
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Antennas : Magnetic Loop

Automatic Magnetic Antenna Tuner - A Magnetic Loop Antenna is a resonant circuit employing a large inductor and adjustable capacitor. Efficiency depends on the inductor's size relative to wavelength. A Magnetic Loop Controller adjusts antenna tuning in real-time, syncing with Transceiver VFO movements. It communicates with various radios, enabling seamless tuning. Stepper motor resolution ensures accurate capacitor positioning, crucial for antenna performance. The Controller's firmware offers diverse functionality, enhancing user experience and antenna efficiency.
[ Hits: 60 | Votes: 0 | Rating: 0 ]

Antennas : OCF

Homebrew an OCF Off-Center Fed Dipole Antenna - This type of antenna is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It’s a dipole fed off center with a 4:1 balun at the offset feed point. The antenna shown covers 80, 40, 20 and 10 meters. The formula can also be used to adjust the overall length to cover more or fewer bands and the resulting overall length. 160-10m, 80-10m or 40-10 meters depending on your available space. Other bands will require a tuner.
[ Hits: 198 | Votes: 3 | Rating: 6.67 ]

Antennas : Tuners

A Versatile SOTA Antenna Tuner - This is a detailed, technical piece, intended mostly for makers and more creative activators, who enjoy building and using their own tools on the summits. A multiband portable antenna tuner supporting 10W, small and light, suitable for SOTA operations
[ Hits: 265 | Votes: 2 | Rating: 10 ]
Portable T-Match ATU - Homebrew Portable T-Match ATU, VK1AD Portable T-Match Antenna Tuner (ATU) mounted in a plastic case, T-Match ATU Schematic – 3.5 to 52 MHz power rating 80 watts
[ Hits: 103 | Votes: 1 | Rating: 8 ]
Homebrew Z-Match Transmatch - For this project, I decided to try my hand at building a Z-Match tuner from scratch. This type of tuner has been around for a while. While the Z-match can take on several variations, what distinguishes it from other circuits is that it is a resonant circuit that uses a fixed inductor.
[ Hits: 132 | Votes: 0 | Rating: 0 ]
QRP Z Match Antenna Tuner Project - A Home made antenna tuner for QRP transceivers. This small tuner is the ideal for portable operations with random length wires or whenever you have not a resonant antenna.
[ Hits: 109 | Votes: 1 | Rating: 10 ]
Budget-Friendly QRP T-Tuner and SWR Bridge - In the pursuit of an affordable matching and SWR indication solution for the Pixie-based transceiver system this T-Tuner and SWR bridge unit, while not groundbreaking, proves to be a cost-effective performer. With real-world impedance testing yielding a worst-case loss below 0.9 dB, the unit efficiently matches all bands on 80 M to 10 M ham bands, making it a valuable addition to the QRP system.
[ Hits: 82 | Votes: 0 | Rating: 0 ]

Antennas : Wire

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.
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Operating Modes : QRP

Antennas for QRP Operation - Antennas for low-power operation resemble those for 100W use. Minor adjustments, like capacitor voltage ratings, may apply, but basic principles persist. Portable antennas, notably Backpack Antennas for weight-conscious setups, hold relevance beyond QRP. While some antennas function acceptably at higher power, efficiency issues arise at QRP levels. Testing antennas at 100W exposes weaknesses, particularly in tuners, crucial for efficient QRP operation.
[ Hits: 88 | Votes: 0 | Rating: 0 ]

Radio Equipment : HF Transceivers : Icom IC-7300

ICOM IC 7300 mods - Modifications for the ICOM IC 7300 transceiver, MARS mod, antenna tuner coverage expansion, Mic Modification
[ Hits: 666 | Votes: 3 | Rating: 7.67 ]

Radio Equipment : HF Transceivers : Icom IC-7851

ICOM IC 7851 Reception comparison - Reception test comparison between IC 756 pro III, IC 7700 and the last jewel by ICOM IC 7851
[ Hits: 89 | Votes: 0 | Rating: 0 ]

Technical Reference : Arduino

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 ]

Technical Reference : Ham Radio Go Kits

Yaesu FT-891 Go-Box for POTA - This article documents the author's latest go-box build for outdoor ham radio operations using a Yaesu FT-891 transceiver. The go-box is constructed from a plastic "50-cal ammo case" and contains various components, including the transceiver, LDG Z11 Pro autotuner, DIY Yaesu FH-2 remote control keypad, and an external battery. The author details the design considerations, the mounting of components inside the box, and addresses issues related to ventilation and cable management. The go-box is geared for CW operations and POTA activations, with further modifications planned for a microphone and DATA jack. This project allows for rugged, environmentally protected outdoor radio operations while maintaining portability.
[ Hits: 196 | Votes: 0 | Rating: 0 ]