Welcome to
Rick Andersen's
Simple Home-Built Radio Page

Projects and Schematics

(See hyperlinks to radio circuit schematics at bottom; but first, some hot air from your sponsor...)


I've finally gotten a nice little digital camera that's allowed me to start adding pictures to the webpage to spruce it up a little. Hope you find them helpful in building your own versions of the simple radio circuits here!

I am a Ham (Amateur) Radio operator, callsign KE3IJ. As such, showing a good, progressive image of Amateur Radio, being "cool", and all that, dictates that I should be flushed with all the latest digital, solid-state equipment in my radio "shack".

Pfeh.

I am a homeowner with a mortgage and an old car and have (or at least ought to have) been on a budget for as long as I can remember. No shame in that, unless you let "them" convince you otherwise. My "shack" consists of a Kenwood TS-520S (1970's or 80's vintage), an old Drake 2-B tube receiver from the 1960's which I use as a backup receiver, a kit-built Ramsey 2-meter FM transceiver, and various other "boat-anchors" and pieces of junk. I run less than 100 watts into a horizontal full wave loop antenna that's resonant around 2.6 MHz, but with an antenna tuner can be used on all bands including 160 meters. I don't have any digital mode capability - not even an old TNC - and that suits me fine.

    
    

Most of the PCs in my house are of 486 vintage running DOS or Windows 3.1. The computer I use to get on the Internet and publish this web page is an early Pentium running Win 98.

[UPDATE: I've graduated to Win 2000 since 2005, so I now tend to be about 5 years behind the times, instead of at least 10 years behind the times! Now maybe I can start thinking about getting a cell phone!...
2008 UPDATE: I now have a cell phone. But no Pager, IPod, Blackberry, Bluetooth or DSL/Satellite Internet Access. I guess I'll never catch up ;-( ]

And now that I've resigned myself to being a Windows user, that suits me fine, too. Now if they would only stop modifying HTML and Java and Flash and all that other crap that causes my IExplorer to work well last year but not so well this year [FireFox to the rescue!].

You'll notice that this website loads pretty fast because the emphasis here is on text information rather than glitter, sizzle, and cartoons. Well, except for this page, with all the pictures.

Anyhow, being someone who can't afford the Latest and Greatest, but often having enough change to buy a few goodies from Radio Shack, I, like most hams, have accumulated what we guys lovingly refer to as a Junque Box (well, mine is not really all in a "box" as much as it is sort of randomly distributed all over my basement) of parts and goodies which allow me to tinker and "play" when I get the hankering -- brainstorming on some minimalist radio circuit and lashing it together to see if it will work.

Why am I not on the air as much as I'm tinkering with toy radio circuits? Well, if some of the hams reading this don't mind my saying so, the manners of many of the people using the bands these days leaves so much to be desired that I often find more pleasure in futzing around with "minimal" QRP [low-power] ham-band transmitters and receivers, as well as good-old AM broadcast receivers, than in getting on the air anymore. I like to "rag-chew" mostly; seems like the bands consist of Nets, frantic-paced Contests, and DX, where "you're a 5-9" is the only thing the participants want to hear in a slam-bam-thank-you-ma'am radio exchange, even when you're cranking out 1/10 of a Watt into a coat hanger and you know damn well that Akhmed from Zanzibar couldn't possibly be hearing you that well!

(Yeah, I'm crotchety; it's good to have a Web Page!)

So I've found a certain twisted fascination with trying to build the simplest pieces of junk possible, and seeing what I can pick up with them. I usually start by drawing a rough schematic on paper, then tack-soldering a haywire "spider-web" of components, as a 'first pass,' and then I rebuild the circuit more neatly once its design is finalized.

It still amazes me that we can connect some modified "rocks and sticks" together (that's basically what copper wire, silicon transistors, etc. really are, when you think about it) and hear voices and music magically appear out of nowhere-- and without batteries, too, in the case of the Crystal Radio and the "Free-Power" receiver described in the articles below.

And "Regens" -- Regenerative and Superregenerative detectors -- have fascinated me since my teens (1970s, if you must know). I have a 1-transistor superregen that I built to hear the VHF Aircraft band -- this radio can "hear" the local oscillator inside a small Radio Shack transistor Aircraft radio -- across the yard 30 or more feet away. When I tune the store-bought superhet back and forth, my 1-transistor homebrew Superregen receiver picks up a 'full-quieting' spot that goes away when I switch the commercial radio off, 30 feet across the back yard. That's impressive, to me. (No wonder garage-door openers use modernized versions of the superregen).

I fear that the generation younger than me is losing the thrill, the magic, that my generation was one of the last to experience -- building a Heathkit, or an Ameco, or a Knight kit, or "rolling your own" And rolling your own is what the schematics below are all about.* Have fun!!!

[Note: In the spirit of "rolling your own", my articles present a schematic diagram and a written description of each project. Layout, assembly method, parts lists, and installation in a box or case are all up to you. I am better at designing on-the-fly radio circuits than I am with metal- or woodworking, and my mechanical skills are mediocre at best. So please use your creativity to come up with your own packaging -- [TRANSLATION: Since I am already giving you the schematic diagrams for free, and never asking you to donate $$ to help me pay for this website, Stop emailing me with requests that I supply you with parts, sources and pcb layouts] -- you'll probably build something much nicer than I'm capable of doing, and your chest will swell like a proud parent showing off the new baby to admiring relatives.]


* Of course I must tip my hat to the many companies and individuals out there who are keeping kit-building alive in the QRP community. But even these simple kits can be pricey. Now, I'm aware that it's not really worth it to roll your own radio receiver anymore-- but it's not about what's "worth it". Gardening isn't worth all the trouble and expense and weather and bugs -- but millions do it every Spring for exercise, therapy, the sheer pleasure of it, and, yes, because there's something really special about food you've grown yourself.

Receivers

Revised February 2010 - NEW! The DC-80 Direct-Conversion Receiver with 'Polyakov'-style VFO at half-frequency

July 2008 - The AGC-80/40 Dual-Band Regen with Audio-Derived AGC

October 2006 - How I build my Radio Circuits -- "Ugly Construction" Over a Ground Plane

February 2004 - A simple Crystal Radio - no batteries needed

June 2007 - Build a FREE-POWER, Batteryless One Transistor AM Radio!

December 2000 - Using the earth as an "underground antenna"

March 2007 - The AGC-80 - A Colpitts-style Transistor Regen with AGC for 80 meters

March 2007 - The AGC-80/30 Dual-Bander - The beginning of a transistor "Regenerodyne" with audio-derived AGC for 80 and 30 meters

October 2004 - A "Universal" Regen circuit that can be adapted to AM, SW, or FM!

December 2006 - A Single Transistor, "Big Loop" Regen AM Radio

October 2006 - A 2-transistor Superregen for FM broadcast or VHF aircraft

May 2005 - The "40 Meter Tweeter": A No-Tuning-Cap Regen for 40 meters CW!

January 2006 - A 2-transistor JFET-based Regen for 40 meters [REVISED for NON-TOROID COILS 1/15/2006]

February 2004 - A 2-transistor Reflex AM radio that drives a 4" speaker!

November 2004 - A simple Audio Amp for your radio, made from generic transistors

Transceivers

March 2005 - The "RixPix" -- My version of the Pixie transceiver


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