circuit design

W3FF Portable Dipole  ^pop - This is the antenna w3ff designed for his walking portable station. It is a dipole constructed out of the plastic plumbing pipe CPVC. There are telescoping whips at the ends of each side of the dipole, and these whips are adjusted to bring the antenna into resonance on each of five HF Bands 10, 12, 15, 17, and 20 Meters

Stacked 7-Element-2m-Yagis - These yagis and groups were designed with YO7.23 from K6STI and checked with EZNEC from W7EL. With a gain of 14/17/20dBd they have a good relation between gain and mechanical problems.

A turnstile antenna for 2-meter ARDF - Antenna design for use with hidden transmitters on international-rules ARDF events

A 6m portable 4 element quad - This antenna is based on a design for a portable 2 element 6m Quad by VE7CA, which is featured in the 19th Edition of the ARRL Antenna Handbook

Home Brew VHF UHF dual band antenna  ^pop - Contructing precedure and tune up of a dual band mobile antenna. This antenna is just a 1/4 wavelength resonator for both UHF and VHF band. It provides no GAIN as compared to other multi-section design.

PAC-12 Antenna - mobile multiband  ^pop - Here’s an award-winning, easy-to-homebrew, multi-band portable vertical antenna designed by long-time antenna aficionado James Bennett, KA5DVS. He’s documented the design and construction plans for a portable antenna that can be built with relatively ordinary components

N4EKV.COM - Antenna Tuners - Homebrew balanced-L antenna tuner. Covers 160-10m. Designed specifically for balanced feedlines.

PAC-12 Vertical portable antenna - Build the PAC-12 Antenna a multi-band portable vertical designed by KA5DVS, here’s an award-winning, easy-to-homebrew, multi-band portable vertical antenna designed by long-time antenna aficionado James Bennett, KA5DVS. He’s documented the design and construction plans for a portable antenna

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.

Otto engineering - Otto engineering is comprised of two divisions otto controls and otto communications. otto controls designs and manufactures a full line of switches and grips used in heavy equipment, aerospace, marine, medical and other demanding applications. otto communications designs and manufactures audio accessories for two-way radios used in public safety, police, fire, retail, hospitality manufacturing and other markets.

SoftRock-40 - The SoftRock-40 is a small, low-cost, good-performing "software defined radio" receiver that plugs into a computer USB port and delivers I-Q audio signals to the computer's sound card. It was designed by Tony Parks, KB9YIG and Bill Tracey, KD5TFD as an "SDR sampler project" for hams everywhere to easily try out software defined radio.

Q15X25 - Q15X25 is a packet modem with a KISS/AX.25 interface designed for HF transmission of AX.25 packets and TCP/IP using Automatic Repeat reQuest (ARQ) and forward error correction (FEC).

JT65 - JT65 is a digital protocol intended for Amateur Radio communication with extremely weak signals. It was designed to optimize Earth-Moon-Earth (EME) contacts on the VHF bands, and conforms efficiently to the established standards and procedures for such QSOs.

Far circuits - Direction finding projects, useful tools for t-hunting operations

HRX80 80 meters receivers for APRS - 80-meter peilontvanger / receiver includes printed circuit sample and list of components

Amsat DSP Satellite Transceiver Project - The DSP Satellite Transceiver is a conceptual transceiver designed as a dedicated unit for amateur satellite operators. The initial concept was brought about by the lack of satellite functionality on modern amateur radio transceivers, and the specialized requirements of the ham radio operator who utilizes OSCAR amateur satellites.

Qsk keying for yaesu radios - QSK amplifier keying circuit for Yaesu FT-1000MP, FT-1000MP Mk-V, FT-1000/1000D and FT-920

FM transmitter kit for 88-108 Mhz - 3 Watt fm Transmitter Hobby Kit 88 - 108 Mhz. Kit Includes Glass Fibre Printed Circuit Broad High Quality Componets Full Instructions

Qsl factory - qsl cards - Qsl card printer and designer offering truly original styles of quality single and double sided color qsl cards, both ready-made and custom.

Ham Gear - Ham Radio T-Shirts, Caps, Mousepads, also vintage designs! Designs include logos from Amperex, Collins, Eico, Eimac, Gonset, Hallicrafters, Hammarlund, Heathkit, Johnson, Knight, Mars, National, Swan, Skywarn and others.

QST signalink review - SL-1 - Designed to handle audio signal interfacing as well as transmit/receive switching Reviewed by Steve Ford, WB8IM

Grounding and RFI - Described system was designed to provide a high level of lightning protection - there are three levels of defense to guard against let-through. It isn't perfect, but does, however, follow good guidelines and shows measured improvements in RFI reduction.

The smk-1 on 20m - Taking the venerable SMK-1 design to 20m and adding an RF amp, audio filter, and a TiCK Keyer ... by Wayne McFee, NB6M

Are you ready for BPL - Broadband over power lines (BPL) is a technique for transmission of high speed data (broadband Internet) over powerlines. Access BPL technology injects radio frequency energy into powerlines which were not designed for transmission of radio frequency energy, and leak substantial energy that causes interference to radiocommunications service

Rainbow Antenna Analyzer - A small and inexpensive measurement device designed to determine antenna performance across the amateur bands through use of automatically collected SWR readings