circuit design

WE6W Field Day Antena design - Interesting article on how build your own field day antenna

An 80-160 magnetic loop antenna - A classic diamond shape loop antenna that works fine on 80 and 160 meters band. This loop design allow a few watts power only and include part list and construction details.

Magnetic Loop calculator - Windows antenna design program for magnetic loops antennas by DG0KW

Design your Own Super J Pole - Javascript for calculating the lengths of tubing to be used for the construction of a Super J-Pole in a collinear design

Dipole antenna - Overview, summary, tutorial about the dipole antenna or dipole aerial that is widely used on its own and as the basis for other antenna designs.

K7MEM - Folded Dipole Design - Design your own folded dipole antenna

K7MEM - Inverted V Antenna Design - Inverted V antennas is a dipole with the center raised on a mast and the endpoints near ground. Calculate dimensions online.

Comparator-based RF switch - This is a concept paper, not a constuction article. There are too many variables to propose a one size fits all design. However, this paper should give you the basic idea how to do it

Radial System Design - Are the lengths of antenna radials related to the height of a vertical? By N6LF

Design a J-pole Antenna - Enter the operating frequency in MHz to calculate the dimensions for your J-pole.

Antentop: Loop Antennas - Article on radiation patterns of small loops, equivalent circuits of loop antenna, small loops as receiving antennas, ferrite loops

Pocket Loop Antenna - The Pocket Loop is a small magnetic loop antenna designed for a carry anywhere operation, it disassembles in 33 centimeters pieces that can be carried even on an attaché handbag.

TrapDip - This program let you design and performance of 2-band trapped dipole antennas including trap design.

CoaxTrap - This program let you design of antenna trap using length of coaxial line wound as solenoid on a coil former.

VE6YP CoaxTrap - The Coax trap program computes design parameters for the construction of coaxial traps for HF usage. Typically these are constructed from PVC tube and RG58/59 coax

Z Match for High RF power - Based on VK5BR's Z-Match and designed for High RF Power covers 160 to 10 meters by VK6YSF

FM Transmitting Antenna - The antenna system about to be described here is a superset of the classic "J-Pole" design, a 4-bay J-Pole antenna

The Electchester VHF Club - The electchester vhf club is located in flushing, queens, ny and operates an arrl coordinated, 2 meter, vhf repeater designed for amateur (ham) radio use.

Rajessh Eng. The Tower Company - Rajessh Engineers is a general Purpose designing, fabricating, and commissioning of communication towers, transmission towers, sub-station structures and their accessories. Rajessh Engineers located at IT Highway, Sholinganallur, Chennai, Tamil Nadu, India. Rajessh Engineers is an engineering steel fabricating company to meet the highly specialized needs of the communication, power industry.

ExpressPCB - Free PCB software is a snap to learn and use. For the first time, designing circuit boards is simple for the beginner and efficient for the professional.

RUMPed - RUMped is a logging tool for short wave for the MAC under OSX. It is not designed for the daily QSOs. Currently RUMped supports a DX-pedition mode, some major contests and a general contest mode for unsupported contests.

Codec 2 - Codec2 is an open source low bit rate speech codec designed for communications quality speech at around 2400 bit/s. Applications include low bandwidth HF/VHF digital radio.

4 x 813's RF Amplifier Deck - This amp project was an exercise in cheap! The design criteria was to use only components in the JUNQUE BOX

NiCad battery charger - A basic nicad battery charger using a single medium power transistor.

Universal QRP Transmitter - Here's the homebrew Universal QRP transmitter adapted from work by Wes Hayward - W7ZOI. The circuit originally appeared in QRP Classics published in 1980 by the ARRL