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Lightweight 144 MHz Yagi antenna - A Lightweight 2m Yagi for SOTA. The boom is 20mm PVC electrical conduit and the elements are 2.4mm aluminium TIG welding rod. The antenna is carried as a single length of conduit with the elements stowed inside the boom, sealing them in with a bung. The driven element is connected directly to 50 Ohm coax with a BN-43-202 balun core to decouple the coax shield.
[ Hits: 180 | Votes: 0 | Rating: 0 ]

HF Multiband Moxon Antenna - A project that describes a build a multiband wire beam antenna. A 3 band single feed moxon antenna for 20,15,10 meters.
[ Hits: 709 | Votes: 13 | Rating: 7.54 ]

Portable Vertical Antenna - A home made portable vertical antenna, that with a single 1/4 wave counterpoise wire is possible to achieve less than 1.5:1 SWR on 40, 30, and 20 meter bands. It is basically a center load, shortened ground plain vertical antenna.
[ Hits: 362 | Votes: 0 | Rating: 0 ]
3 Band Mono Loop Portable Quad - Handmade drawing of a 3 bands single loop, portable quad antenna used by the author during his dx pedition in Kenya as 5H3FM. This antenna is done using 3 telescopic spreaders and the spreader kit for 1 element quad by spiderbeam.
[ Hits: 133 | Votes: 0 | Rating: 0 ]

Active 3-30 MHz Hula-Loop Antenna for Shortwave - This active antenna for the shortwave band provides surprising performance, even indoors. As the name implies, the main loop is made from a Hula-Hoop with the metallic paint stripped off and a single turn of 14AWG copper wire inserted inside the hoop.
[ Hits: 159 | Votes: 1 | Rating: 10 ]

Improve your Antennas for Low Solar Activity - How to improve your transmitting antennas for very low solar activity periods, vertically polarized 160 meter antennas, horizontally polarized 80 to 10 meter antennas, single or stacked yagis, multi-tower stations
[ Hits: 424 | Votes: 0 | Rating: 0 ]

Z Match with Toroid - A single coil Z-Match. This QRP version by G3WQW, using a T130-2 toroidal inductor and polyvaricon variable capacitors was published in Sprat 84.
[ Hits: 100 | Votes: 0 | Rating: 0 ]

W3DZZ Multiband Antenna - An easy to build and extremely high performance antenna, works perfectly on all HF bands 3.5-28 MHz with some compromises, it is basically an half wave dipole for 40-80 meters, an LC circuit or trap 40 meters allows you to use a single radiating element.
[ Hits: 464 | Votes: 3 | Rating: 7.67 ]

Reducing the Cable Mess - Optimizing the cable connections for cat control and audio input output by implementing the digirig mobile. A small audio and rig control interface, with a single USB cable supports most QRP radios requiring external audio and CAT control facilities
[ Hits: 155 | Votes: 0 | Rating: 0 ]

Fundamentals of Radio Waves Propagation - How radio signal get propagated throught the atmosphere, the role of the ionosphere, the thropospheric ducting, single hop and multi hop propagation, the sporadic E propagation
[ Hits: 97 | Votes: 4 | Rating: 7.75 ]

Enhancing Icom IC-7300 RX Antenna - Despite the model limitations, such as a single TXRX antenna connector, the author shares a reversible modification involving a coax relay for enhanced functionality, demonstrating the transceiver's adaptability and customization potential.
[ Hits: 188 | Votes: 1 | Rating: 10 ]

mini Ring-Core-Calculator - Calculate windings on ferrite cores - The program can be used to calculate inductors (coils) and their number of turns on ferrite cores, ferrite shells and air coils. These can be used for baluns, Ununs, bandpass filters, low pass filters, resonant circuits, and more. The technical specifications of the cores are already integrated in the program. Application is free and runs on Windows 32 bit versions only. To make it run on Windows 10 64 bit need to be unzipped in a single folder.
[ Hits: 399 | Votes: 1 | Rating: 1 ]
One-turn loop inductance Online Calculator - The high-frequency inductance of single-turn loops of various shapes made of round wire can be estimated accurately with a simplified formula
[ Hits: 122 | Votes: 1 | Rating: 10 ]

70cm Beacon - PLL synthesized 70cm CW beacon exciter. The exciter is built arround a slightly more advanced ADF-4351 single chip PLL synthesizer rather then (among amateurs) more popular Si-570 or Si-5351 integrated circuits. The exciter is capable of providing up to 250 mW of RF output power,
[ Hits: 131 | Votes: 1 | Rating: 10 ]

CW Keyboard and Keyer - A Combination CW Keyboard and Paddle Keyer. It uses a single Atmel microprocessor, the ATmega328P from the AVR family, and a 4 row by 20 column LCD display module.
[ Hits: 264 | Votes: 1 | Rating: 8 ]

Gimme Five - QRP SSB Transceiver - Gimme Five reloaded, a compact 5 band QRP SSB transceiver in SMD technology. This unit covers 5 bands within the amateur radio spectrum (3.5, 7, 14, 21 and 28 MHz). Receiver is a single conversion unit with an interfrequency of 9 MHz. Transmitter uses 5 stages and has got a power level of 10 watts PEP output.
[ Hits: 285 | Votes: 1 | Rating: 10 ]

How to Measure SWR - A guide to measuring SWR with different types of SWR Meters, the single needle and dual needle meters
[ Hits: 408 | Votes: 0 | Rating: 0 ]

ADF4351 Signal Generator - Just a simple signal generator based on ADF4351 module from fleebay allows you to generate one single frequency that can go up or down in 100Khz steps via two push buttons.
[ Hits: 149 | Votes: 2 | Rating: 10 ]

Transverter for 50 70 28 MHz - This multiband transverter project features power output at 13,8V 50MHz 15W, 70MHz 10W, second harmonic <65dBc. Single N connector of antenna, suitable for a dual band Yagi. Article include Block Diagram for Dual Transverter and low pass filters
[ Hits: 153 | Votes: 1 | Rating: 10 ]
2m to 70cm Transverter Circuit - A 70cm / 432 MHz Transverter Project transverter circuit is an electronic device that converts a radio signal from the 2 meter to the 70 centimeter band and vice versa, allowing a single transmitter/receiver to be used for both bands. It consists of an IF stage, local oscillator, frequency multiplier, and amplifier. The circuit must be designed for minimal signal loss, noise and intermodulation distortion.
[ Hits: 82 | Votes: 0 | Rating: 0 ]