Products

P3ST Modular Transceiver Kit

P3ST Modular Transceiver Kit

After several months of development, MDRF is pleased to offer this kit version of N6QW's P3ST SSB transceiver for 15, 17, or 20 meters (it can be built or modified or any one of these). It's ...
PWR-1 Power Protection and Filter

PWR-1 Power Protection and Filter

Available January 1, 2024. 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 ...
ADE-1 Double-Balanced Diode-Ring Mixer

ADE-1 Double-Balanced Diode-Ring Mixer

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 ...
BFR106 NPN 5GHz Transistor

BFR106 NPN 5GHz Transistor

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 ...
UDVBM-1

UDVBM-1

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 ...
PG-TIA Broadband IF Amplifier

PG-TIA Broadband IF Amplifier

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 ...
HyCas IF Amplifier with AGC

HyCas IF Amplifier with AGC

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 ...
TIA-AGC IF Amplifier

TIA-AGC IF Amplifier

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 ...
8-Pole QER Crystal Filters

8-Pole QER Crystal Filters

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

Dual-Gate MOSFETs

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 ...
OA741D Op-Amp

OA741D Op-Amp

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 ...
GP Audio Amp

GP Audio Amp

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) ...

There’s more coming! Subscribe to be alerted.