Projects

A brief project description is listed below for currently available PDFs.  You are free to use any of these for your own personal use with the agreement any and all liability for that use is assumed by you.  

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PS-15D-25A 13.8 VDC, 25 ADC Linear Power Supply

Our Ham club and the ARES® group it supports obtained a new location for its 2M repeater.  So a new one was built for the mountain and the old one kept for back up, complete with duplexer and antenna.

The new repeater has a 75W transmitter, so I built this power supply that will provide 25A at 100% duty cycle, at or near sea level, up to +40C ambient using only convection cooling.  It also has fold-back current limiting at around 33 ADC.

Remote Antenna Switch

Update of the RA-20A-1. This remote antenna switch is built using printed circuit boards and includes the ability to select one of five antenna systems from the tower mounted remote.  It also can select a local auxiliary output and up to three transceivers using a "local" remote RF switch.

Printed circuit boards for these projects are available from Far Circuits.  The EL-10A -1 boards may be ordered direct under part numbers EL10A121 and EL10A122.  Other projects require artwork which I will send to Far Circuits, CHARGE FREE, for anyone who wants to buy a board.  Far Circuit charges $0.50 per sq. inch for single sided, etched, drilled, solder platted boards including top side legend.

I use Far Circuit boards in my prototypes and they are excellent.  

Mouser Electronics is the preferred supplier for all my projects and other prototyping needs.  While many excellent suppliers exist today, Mouser has consistently met or exceeded my expectations for product availability, pricing and above all service.

AP-10A-1 ARS Portable Power Unit

Portable Power Unit with self contained 35 Ah battery. Selectable straight 12 VDC battery or Regulated Boost 13.25 VDC output.

AA-10A-1. 25 Watt Audio Amplifier.

A simple self contained audio amplifier capable of 25 Watts (true rms) output. Line input for mono or stereo program source such as computer sound card, audio players or other devices compatible with -10 dBv, 10k Ohm line levels. High impedance microphone input with built-in mic preamp. 

VM-10A-1. True RMS Volt Amp Meter. High quality, low cost instrument that measures true RMS voltage and current using LTC1966 RMS to DC converter chip. Ranges of 0.02 to 200 V(rms) and 0.02 to 100 A(rms). External Current Shunts minimize insertion resistance and allows both RMS and dynamic current measurements.

PS-15D-( ) updated (Sep 2017) document with new FAQ section now available at PS15D090 

PS-15D-( ). 13.8 VDC Power Supply. Simple transistorized (no ICs) 13.8 VDC power supplies at 3 to 30 ADC output current with regulation better than 0.1%.

PWB available from Far Circuits.

EL-10A-1. Electronic Load.

400 Watt, 40 VDC, 40 ADC, compact Electronic Load for design and testing of power supplies, batteries, solar power systems, DC power distribution systems, rectifiers and more.  Project is complete and ready to download. The two EL-10A-1 printed circuit boards may be purchased from

Far Circuits for $9.80 per set plus $5.50 Priority shipping. 

PS-40A-1. AC Bench Power Supply

AC Bench Power Supply that delivers up to 5 A from 12 to 130 VAC or direct line voltage up to 10 A.  Includes digital voltage and current meters and external monitor points.

MC-20A-1.  Monitor and Control.

Control 13.8 VDC power to your station with this remotely operated control box.  Provides voltage and current monitoring, DC buss on/off switch, fuse, over voltage shut down as well as under voltage disconnect to protect lead-acid batteries from over dis-charge.  Design maximizes battery utilization by reducing distribution losses rather than some techniques that draw the battery down faster and faster as it dis-charges.