circuit specialists

The 4X4 Slimtenna - Development of the Slim Jim antenna for HF

Adding 160 meters to the Heathkit SB-220 - There will be radical changes to this Heathlit SB-220. There will be the addition of 160 meters along with many other circuit and design changes.

Viking Vintage - Restored vintage amateur radio, shortwave & other electronics from the vacuum tube era! Specialists in restored Ham Radio boatanchors

All Cases - Shipping case and custom foam specialists

AFR Enterprises - AFR Enterprises a leading distributor of electronic components, semicondustors, diodes, Resistors, Integrated Circuits across the USA.

Transistor PA Biasing - Here is a simple circuit that can deliver the peak base current needed for linear ssb operation

Transistor PA Biasing - Here is a simple circuit that can deliver the peak base current needed for linear ssb operation

Integrated Circuit Audio Amplifiers - Circuit designs for IC audio amplifiers by N1HFX

Design Guidelines for JFET Audio Preamplifier Circuits - Design Guidelines for JFET Audio Preamplifier Circuits By Mike Martell N1HFX

Recovering old NICAD and NMHI Cells - Old Nicads batteries and sometimes NMHI batteries usually end up with several cells being short circuit, as they suffer from crystal growth in the electrolyte

Adjustable Regulated Battery Charger - This battery charger circuit is regulated and adjustable to make this circuit able to charge the mosto NiCAD battery.

Semiconductors - Semiconductors, diodes and transistors, intregrated circuits

RF Dummy Load - The use of dummy load is mandatory for off-air adjustment of the transmitters. Build one.

Circuit Laws - Basic electronic circuit laws

A high perfomance Crowbar Circuit - The MC3423 can protect sensitive circuity from power supply transients or regulator failure when used with an external "Crowbar" SCR.

DC RF Sensing PA Switching - Circuit for dc/rf sensing pa switching from g8mny

Noise Bridge Tuner Tuner - Noise bridge circuit to tune your tuner

QLF Filter - Microprocessor based interface designed receives a signal from a Morse key, processes it, and re-transmits it to the radio. A microprocessor in the circuit is pre-programmed with a proprietary algorithm which makes a number of measurements and adjustments to the less percise human generated code.

A low cost morse Trainer / Keyer - By Prof. T. K. Mani - VU2ITI

FT290 CW KOX Circuit - This is not actually break-in but just KOX circuit. It can only be used on the CW mode otherwise it keys up the Tx

Non-relay instant RF Switching - Coax lines to do the RF switching. The advantages are instant switching, no power wasting DC control circuits.

An Accurate Power Meter For QRP Ops - A circuit using two junkbox transistors and a garden variety op-amp that will let you accurately measure your rig\'s flea power down to milliwatts.

30 m Band Direct Conversion Receiver - The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take a few hours at the weekend to construct.

Oscilloscope Tester - Circuit to assist in the setting-up and calibration of oscilloscopes

UHF on a VHF Rig - This circuit enables fair copy of strong 444 MHz signals, off a local repeater, using a 2m rig and a 1/4λ 70 cm indoor ground plane antenna.