A Crystal Heater construction project - OK, here is the circuit I used - See image below. The original National Semiconductor circuit had a 30 K resistor in series with a 400 µF cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section. I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 µF cap in series with the 10 megohm resistor to 5 µF. __ Designed by Bob Dengler NO6B
A Dirt-Cheap, High Current Power Supply - Here's yet another use for that pensioned-off AT computer that's gathering dust in the corner.__ SiliconChip
A Dual Mode Superhet/Direct Conversion AM receiver for 181.818 kHz Lowfer ATtiny2313, AT90S2313 - This is a description of an experimental AM receiver for VLF. it is crystal controlled to receive 181.818 kHz (more or less) and operates as either a single conversion superhetrodyne or a direct conversion receiver. The bandwidths are expected __ Designed by Dick Cappels
A dummy load & power meter for HF (PDF) - Not everyone can (or wants to) afford that paragon of dummy loads, the Bird wattmeter, or for that matter the rather cheaper but still extremely good dummy load sold by Dick Smith. And getting your hands on the parts to build the dummy loads in the ARRL handbook isn’t too easy either. But here is a dummy load and power meter, which you can build from standard parts, which covers the HF range and doesn’t cost an arm or a leg. __ Designed by Jim Tregellas VK5JST
A GPS Module for Your PC - Link it to your PC and trace your position on and on-screen map. There's lots of freeware and shareware to use with it as well.__ SiliconChip
A GPS Receiver Based Frequency Standard - Frequency accuracy has been a topic of special interest to many amateurs and experimenters since the early days of radio. Until recently, the best frequency standard available to most hams was a crystal oscillator carefully adjusted to zero-beat __ Designed by Brooks Shera, W5OJM
A GPS-Synchronised Clock - Tired of resetting the time on your wall clock? This GPS circuit will convert a standard battery wall clock into a precision timekeeper that never needs to be corrected. it will even automatically adjust for daylight saving time.__ SiliconChip
A Loud & Sensible Crystal Set Radio Design. - i'm very well balanced, in that I'vebeen harbouring some electronic chips on both shoulders over the years. Here is some redress, and I hope some clarification. __ Designed by Henry
A Low Cost 4Mbps IrDA Receiver in MS8 & SO-8 Package LT1328 - DN152 Design Notes__ Linear Technology/Analog Devices
A magnetic loop antenna for 160 to 15m - amateur radio construction projects. __ Designed by Peter Parker
A magnetic loop antenna for 40 to 17m local & DX contacts from tight spaces - amateur radio construction projects. __ Designed by Peter Parker
A Phone Line Busy Sensing - if you need to share a phone line between your home and a repeater, here's how. __ Designed by Monte Smith, WDŘDIR, from ACC Notes, April, 1986.
A QRP DX antenna - amateur radio construction projects. __ Designed by Peter Parker
A quick receiver - A Direct Conversion receiver is nothing more than a mixer, an AF amplifer and a stable oscillator. I took one of my standard building blocks; a two diode mixer and connected it to my stereo amplifier PHONO input then fed the signal generator into the mixer. Connect an antenna to the third port of the mixer and you can receive HF SSB and CW signals. __ Designed by Harry Lythall-SM0VPO
A Real Yagi Antenna for UHF CB - Are you good at scrounging? All it takes is some plastic conduit and a couple of wire coat hangers to build this really effective antenna__ SiliconChip
A Repeater Fan Controller using a 556 IC - This is a follow-up to the above with a modification to a single 556 chip. __ Designed by George Henry KA3HSW
A SCA Adapter - For Advertisement Free Background Music on FM. __ Designed by G.L. Chemelec
A short wave regenerative receiver - Sensitivity and selectivity are the major concerns of a short wave enthusiast when he looks up for a receiver. Commercial communications models with superhet circuitry surely satisfy his requirements, but these are expensive. He would rather go for a Homebrewed radio, being a regenerative receiver an affordable choice __ Designed by Ramón Vargas Patrón
A Simple Circuit Echolink interface - Easily constructed with about $10 in parts from Radio Shack. Should work with any radio. __ Designed by Courtesy of Matt Krick K3MK
A Simple Circuit loop antenna crystal radio - i love crystal radios and since I could back to my bench a couple of years ago i’ve the opportunity to make some of that. There something fay behind its elegant simplicity… pick radio waves with only few simple components and use the energy of the radio stations to produce directly the sound you’re hearing is something wonderful to me. From very simple sets made from the junk box to high performance crystal radios all of them have its appeal. __ Designed by Marcos Kusnick
A Simple Circuit Repeater Fan Controller - Unlike many repeater systems, our local club repeater has always been located within a member’s home, many times in a basement or in this case, my home office area. The latter created a desire to lower the noise level generated by the repeater, specifically, the power amplifier cooling fans. __ Designed by Robert Shepard KA9FLX
A Single Superhet SSB Receiver for 3.5 MHz - This was my first receiver development that really worked well. Pictures from the outside and the inside of the receiver. __ Designed by Herbert Dingfelder
A Superregen Receiver for FM broadcast or Aircraft band AM reception - This is the receiver I was bragging about on the Radio index page -- the receiver that is so sensitive it can hear the local oscillator inside a small transistor radio 30 - 50 feet away. Build one of these little gems and you will be able to hear aircraft pilots many miles away with nothing more than a 24" whip antenna. __ Designed by Rick Andersen
A to D for Amateur Scientists (Not for Radio-SkyPipe Use) - This is a Radio Astronomy Project __ Designed by Radio-Sky Publishing
A Tone Beep Keyer for Repeaters - Obtain an Audible indication of Off-Frequency Operation. __ Designed by Originally Art Gentry W6MEP. Reprinted from May 1974 QST.
A universal VCO Board using a MC100EL1648DG & a PGA-103+ as buffer - The circuit is straightforward. (as usual). The MC100EL1648 is a voltage controlled oscillator amplifier that requires an external parallel tank circuit consisting of the inductor (L) and capacitor (C). it does the main job. For isolation reasons we added a buffer, consisting of a PGA-103+ from Mini Circuits. (Almost any other will also work). in order to get a "pure" sinewave, resistor R1 is foreseen. it must be optimised empirically. Two voltage regulators are used to ensure stable operation. __ Designed by Alexander C. Frank, aka Ajarn Changpuak
A VHF/UHF/LINK repeater interface/controller - This is a set of nearly identical schematics for circuitry used to provide cross-band inter-agency communications. __
A West Coast Lightwave Project - The receiver we chose to build was a G3XBM modification of one designed many years ago by K3PGP for his laser experiments. it consisted of a small inexpensive PIN photodiode (BPW34) driving a JFET amplifier, followed by several stages of audio amplification (see Figure 1). __ Designed by Steve McDonald, VE7SL & Markus Hansen,VE7CA |