Products

Available June 15th!. Protect yourself from reverse-polarity mayhem and from the assault of noise coming in through your DC power input. At the same time, you can monitor the current draw of your homebrewed rig ...

The circuit of a diode-ring mixer is simple, but making one with good balance, high isolation between inputs, and low-insertion loss is not trivial. It's absolutely doable for a home-brewing Ham, but a wise person chooses ...

A breakout PCB for the BFR106 NPN 5GHz transistor. It’s proven to be useful as a “hotter” replacement for more-commonly used devices. With an transition frequency at 5GHz, there’s a lot more gain available for the ...

I wanted to replace the drifty VFO in one of my rigs with a digital solution, but my hand-wired solution was messy, fiddly, and prone to ground loops and digital noise. So I designed a PCB ...

The performance of a receiver or transmitter depends on careful impedance matching between its sub-systems: its mixers, filters, and amplifiers. Mismatches can cause loss of signal strength, inter-modulation ...

The Hayward-Damm design (published in the December 2007 issue of QST) has long been extolled as excellent, but its complexity has discouraged a number of would-be builders ...

Stop caring how many I/O pins your Arduino or other micro-controller has. Use the I2C two-wire bus and you can have an digital display, an Si5351, a number of other useful devices, and now a rotary ...

Adding automatic gain control to a TIA IF amp makes the audio volume of a receiver as predictable as the impedance of the amp itself. AGC keeps strong signals from blasting-out your eardrums ...

A clean, ripple-free and narrow-skirted "xtal" filter is essential for excellent performance, especially in a receiver. They are, however, among the most difficult builds for a home-brewing amateur to pull off ...

Dual-gate MOSFETs were once common in Ham radio designs, but no through-hole versions are now available on the market. These little half-inch breakout-boards with pre-soldered SMD versions might make ...

The operational amplifier–the "op-amp"–was created to do by analog means what we now do digitally: to simulate mathematical operations. In application, though, op-amps have long been used for so-much more ...

Still in Development! A general purpose, discrete-component audio amplifier with selectable three or four preamp stages. Based on a design by Richard Anderson, KE3IJ (SK) ...