Some of the links are dead sorry.

Dead links will be removed soon.

Links and other Resources
(1 Feb 03)

Projects and info

*The Xtal Set Society - a must-visit site,  a few select links.  Two projects on line.  If you haven't built a crystal set before, the Oatbox Radio is about as reliable as they come, and never fails to bring a smile the face of anyone who hooks it up to an antenna and ground for the first time.  Sponsors a discussion group (see below)
* Bellingham Antique Radio Museum   good tutorial on detectors and a very nice building project.
*Al Klase   -  has an outstanding  page here.  I printed it out immediately.  Includes a short course in Crystal Radio 102,  some neat info on headphone and earplug sensitivity, coil philosophy, and rockstands he's made.  See his super radio using toroid coils.
*Ben Tongue's Web Pages - thoughts on xtal set design and headphone testing.  Very nice info on high level detection and improved impedance matching, diode selection, etc.  A bit technical for many, but has some good directions for getting a high impedance match to the tank circuit.
* Crystal Radio Web Site    Darryl Boyd's site on sound powered phones, oodles of "lost" crystal set construction articles and a bunch of other stuff just keeps getting better.  Largest collection of published crystal set plans available.
*GOLLUM Detector Page - some interesting circuits, including how to bias a detector .  Updates page occasionally, and now has a couple of FM crystal sets   and a nice looking double tuned selective set. Also sells a kit, but it appears way overpriced.  
* Chapter 4: Radio   nice detailed pictures on their progressive project.  Also has the simplest AM transmitter you'll ever find.
The Ilford Group RSGB (G3XRT) Home Page    has some neat xtal set projects, with a bit of humor thrown in.     
ARRLWeb: Science Fair/Merit Badge Projects has a QST crystal radio project you can download in PDF
CrystalRadios detailed pdf instructions for a classic slider.
*Crystal Set Competition from Queensland Australia - beautiful rigs, and plans for the prize winning Mystery Crystal Set (the rage in 1932).
 Improvement of the "Mystery" some more notes on the original by Ken
*Bizarre Stuff you can make in your kitchen finally found a new home.  Super site.
 Crystal Radio Circuits by Wenzel Associates, with some new stuff on diodes added
 A crystal radio set for Dad's Mum's and beginners A nice site; worth visiting, then visit Ian's very fine Electronics tutorials site.
Loop Xtal Set
Crystal Radio with Loop Antenna
Another loop crystal set
Building a Crystal Radio-Construction
Electronic Circuits has too-simple  xtal set plus one with an op amp booster
Common AM Receivers - Crystal Set Australian college electronics course page.  What the heck, go to the index and take the whole radio course: AM Radio Receiver Project Home Page
Adventures in Cybersound A 'Sensitive' Crystal Radio ,  and   A 'Selective' Razor Blade Crystal Radio .    Both salvaged before Gnome Technologies reformatted their site.  Some nice stuff on alternative detectors.  The rest of this site is great too, including a foxhole radio design by Lance Borden
Antique Radio Page: Articles - "Foxhole Radios"  
WHAMLOG   has many of these links and links to a lot of antenna building sites, and then some.  Bookmark this site.  Werner Funkenhauser keeps this one full of good sites.
Crystal Radio A collection of nice stuff from Dan Peterson, a regular XSS contributor
Medium wave wave trap   sometimes you gotta have one - got this from Whamlog
Ed Ganger's coil winding formulas for single and multilayer and spiderweb coils.
High-Power Crystal Radio a Popular Electronics reprint circa 1960 - claims speaker performance (but don't try it that way unless you have a really strong local)
Building Crystal Sets a variometer project, and more coming soon, so they say.
DIY: Crystal Set Radio on close inspection, the 10 turn primary really should not be connected to the 35 turn secondary; only to the antenna and ground.  Gives you some loose coupling and better selectivity (also might try connecting the detector to about the 10th turn on the secondary instead of at the top while you're at it...).  The web author of this design said his was correct per the original ( but we know better, don't we).  
Jampot.   crystal radio in a jar from .nl land
CRYSTALª@RADIO   site in Japan; nice set, but most writing in Japanese.  Look at the rest of the site too.
Crystal Radio Sets on the Net!   or how to build one similar to the old Radio shack crystal set - nice directions.  An extra winding for antenna loading would help selectivity in my location. More nice stuff, including a MK 484 variation from Austin Hellier.  He'll sell you the parts.
Germanium diode selection   a nice, objective comparison of diodes "over there"
Headphones     how to fix 'em.
Tom Polk's kid radio - what to do with those empty soda cans
Very nice looking XTAL SET
J.W. Miller Hi-Fi Crystal Tuner - the plans and building instructions
Beagle Baly see pix and schematics for the Heathkit CR-1 and the Knight Xtal set, and more.
Here are two homebrew sets from the 20's. Home Built, 1 Crystal Set or  Home Built, 2 Crystal Set
XTAL-SETS.COM  Paul Shafer's new site.  Don't let the .com fool you, he's not selling anything...yet, but really wanted to snag the url.  Has a couple of pocket radio projects for you city dwellers. dead?
The Boy's Book of Crystal Sets - The book is out of print, but here are a couple of schematics from it. dead?
Crystalset.htm   - a novel tuning capacitor in this one from SatCure .  Includes an optional one- transistor amp.  Also look at his index page; lots of neat stuff.  Has some hard to find parts as well.
Rocket radio  instructions for making your own. (found it again).
The Circuit Archive - a new site with a couple of more advanced xtal circuits from the UK wireless presses.  Noodle around on this site and find some more goodies. dead?
Vintage Early Radio      - some very interesting stuff about variometers (variable inductors) , as well as a tutorial on regenerative and reflex receivers
Online Radio & Electronics Course you'll like this one from down under. dead?
Electrical Engineering Training Series.   Courtesy of the US Navy Training command.  Worth reading.
Crystal Set and One-Tube Resources Some nice old stuff here
Zip cord radio antenna don't try this at home, kids.
136khz.htm Read the part about antennas - the long wave guys have to deal with too- short antennas also, to the extreme.
  The Crystal Set Some nice stuff from Brian Hawes' files.
HOW TO BUILD A SIMPLE WIRELESS TELEGRAPH SET two xtal sets and two doorbell buzzers and you're on the air- from across the room.
Marconi magnetic detector try to make one of these and get it working.
FM only: Low Tech FM Radios for those of you who asked
Cristadyne wierd stuff from the past. Got any zincite?
J.C. Bose: 60 GHz in the 1890s very serious crystal sets - not for kids, then jump to the next link for the "cosmic" crystal set
hale-bopp search and you thought xtal sets were just toys...
Producing wound components detailed discussion of coil construction
Inductors. - some dope about coils and such  
The Unusual Diode FAQ
Make this radio motor and do something with that free power besides listening
Museum of American Heritage   take a course on building a crystal radio(if you are a kid near Palo Alto, CA)
Some info on coil losses dead?
Joe Bento's Selectomatch a headphone impedance matching box for all occasions
Crump   has some plans for a crystal set as a power supply .  dead?
Ohms Law:  has an ohm's law calculator,a simple xtal set, and plans for the Heathkit CR 1
Spark, Bang, Buzz and Other Good Stuff. includes making an oscillating diode out of common materials.  Neat page.
An FM Crystal Receiver looks like you can make this one without too much trouble
My Crystal Radio Page some sets by Adam Vaughn
Crystal Set Corner a nice tutorial from  Wireless Review
Rook Coils for Crystal Radios a different way to make basket coils
Philip Miller Tate's Web Extravaganza! Ramblings from Dr. Whiz.  
Middlesex Univesity Offers some novel sets for sale, but you can download the instructions and probably make your own
MODAD Home Page three crystal sets, including a short wave set with an one-tranny amp  
RF Signal Generator
Image 618x875 pixels  a simple dip meter.
AM Box Loop Antenna

A Lyonodyne style Crystal radio Lou may have dug up the original design here.
How to make a Simple Radio Set
Active Antenna for those days when the wind knocks down the tree.
Variometer Design
Crystal set analysis by Berthold Bosch   posted to Gollum's site.  Good read.
Crystal set receiver  A nice UK site.  What the heck is a crocodile clip? Hi.
Crystal Radio.html   a school project using a simple variable capacitor.
Dave Schmarder  has a nice site with his crystal and tube sets.  Will be happy to let you buy as well.
Klunky Schematic Drawing   Make your schematics on line
TubePad 5.0  another way to make your schematics.
Fun With Tubes   starts you off with a crystal set and walks you through building simple one-and two-tube sets.
Crystal Set Projects from the UK
Crystalsets and detectors   Here is a way to use full wave detection with what Kirk Bailey claims detector self-biasing as well for greater sensitivity.
The Crystal Set Designer Pages   From the same bunch that brought you the Mystery set (still a mystery to me).  Will also sell you some software to do your set calculations.
How to Build a Crystal Radio:   How not to build a crystal set!
Crystal Sets   Some history, some tutorial, and perhaps more to come.
Kirk Bailey's    Crystal Set Book download.  A work in progress. Zipped file.


Crystal Shortwave Receiver   looks like it is more trouble than it's worth for a single tuned circuit, particularly with all the bandspread switching.  Too much work and switching for a low performance design. An antenna tuner would probably help.
GW0VMR's Short Wave Crystal Radio Set much easier to make than the one above
Shortwave "Mystery" Crystal Radio with variations, by Ken Harthun
HOMEBREW QRP IS GUD 4 U strip the receiver down to a shortwave passband xtal set, or just build it as shown and copy CW and SSB.  Audio amp optional.
Shortwave Crystal Set     Al Klase's experimental sw set (pay attention here - Al knows whereof he speaks).
Three sets from Gollum:   Number 1 , Number 2 , Number 3
Shortwave Crystal Set by M0DAD (with a one-transistor amp)
HF Crystal Radio Receiver by Rick Weber - from scratch a real winner.  #1 in the building contest.
The Creative Science Centre  build a rough science  shortwave set using a sauce pan capacitor 

International Bureau > FCC HF Broadcasting Page   good info on the shortwave bands.
European Medium Wave Guide    zipped PDF format.  A cheap alternative to the WRTH if you're doing the "locals".
HFCC Public Area Shortwave skeds from the High Frequency Coordinating committee, have to noodle around on this a bit.
Inwit Publishing, Inc. Shortwave Radio Listening Resources - Home   Shortwave listening resources
Prime Time Shortwave Mike Tuggle swears by this site.
Glenn Hauser's World of Radio English shortwave broadcasters sorted by country
The SPEEDX Shortwave & DXing Home page  Shortwave FAQ

YAHOO! PHOTO ALBUM S (more than just pictures)

 Xtal Set Photos by Dr. Whiz
  Charlie's SW Xtal Set
 Loose Coupler's pix
 Mike Lee's gallery
Richard O'Neill's  posting of NBS circular 121 from 1922 on building a still hot crystal set
Bill Hebbert's photos rook coils and other stuff.
Bill Pryor's photos!  nice collection


The Moorabbin receiver a nice two transistor receiver.
One Tube Regenerative Radio Project a radio for a buck? 
NorCal Regen Building Contest at HamCom 99 ham regens with links to others
Diotran Radio - a simple regenny
Regenerative Receivers -Aussie college page with simple schematic and explanation of how they work.  Part of the "course" above.
Harry's Homebrew Homepage    another couple of regens and other interesting stuff
Regenerative TRF Receiver
W2UW's 1-FET transmitter/receiver
Thermoradio a candle powered regenny?  Hmmm.
Thermoradio   a nice page with notes on building the Thermoradio.
Radio Electronics Pages lots of good info plus a link to a nice regenny
One transistor FM radio project a supergenny; pretty straightforward after you assemble the parts.
CK722_Webpage all about the transistor that got many of us started   Bob's site features  an early one-transistor receiver from Knight Kits (oh, where can you find those coils?), a one transistor Heath AM transmitter, and more.
Australian Vintage Radio! See if you can make one of the valveless headphone amplifiers.  Also has a simple little one-tuber.  (gotta make one soon)
Old-Time "Interflex" Radio Receiver Hugo Gernsback made my convertible with a germanium transistor and a tube.  Like me, it took him three iterations to get the selectivity down.
Transistors a nice tutorial on how they work.
Radio Frequency Schematics three projects, including a short wave ZN414 based set, plus a bunch of other nice stuff
Build the Radione and play with Tesla's theories
Regenerative Receivers nice page from Wenzel
N3GO Radio Workshop Project  
Simple Radio

RF ELECTRONIC CIRCUITS A regenny and a reflex
Two Transistor Reflex Radio

A one transistor cathedral radio

Hobby Elettronica il Portale  Italian site, but you can figure out  the details of the two transistor AM Reflex radio
The ingenious circuits of Sir Douglas Hall as published in Radio Constructor    
Philmore radio kit  alas, construction details lacking, but you can make it with perseverence, I think
Simple AM transmitter   some variations on a simple one-transistor AM transmitter.
Simplest RF transmitter
Chapter 4: Radio  a cute way to make the MK 484 receiver.  Will sell you the parts.
SW Receiver Using ZN414
Regen Shortwave Receiver
Simple Radio Experimenter  A nice catch-all site by Steve Owen
The Transistor Museum



Operating aids

AM Query -- AM Radio Technical Information -- Audio Division (FCC) USA   helps answer the questions about why you can't hear them, or can't avoid them- lists frequency coordinated n. and s. american stations- and then go to the next link to:
    Distance and Bearing Calculations Between Two Sets of Coordinates (FCC) USA
How far is it? another distance program with some coordinates of selected cities
CANADIAN AM RADIO DIRECTORY some real dx listed in here- 50 watt stations.
Combined BCB Freq List!   Good lookup for those stations you never heard of.  Includes stations below the MW band.
FCC AM Database Search not the official site, but works nicely, even when the agency budget is still in committee.
BROADCAST BAND DX LOG BOOK    nice layout which shows program formats for many stations; useful for those that only ID once an hour.
Lightning Explorer Free Page gives you a map of the US showing lightning strikes within the last two hours or so - find out where that static is coming from.
Herman's DX Homepage
The DXZone Guide to Ham Radio World
The MIT List of Radio Stations on the Internet
Azimuthal Equidistant (Great Circle) Projection Map   go here to make an azimuthal map with your location in the center.
Earth at Night ever wonder why you never hear some parts of the world?
Earth View   get a real time view of where it's dark, and where it's not
The official U.S. time with a day/night map.
G4FON has as good a morse code tutorial and trainer as you can get for the effort of downloading.  Uses the Koch method of code instruction, but you can just use it to brush  up on your receiving.  

 Parts, sets, and kits
No recommendations on any of these except as noted.   If you have a link to add, tell me and I'll look at it; if you think someone doesn't belong on this "mantle", tell me about it

*Scott's Crystal Radios    Great classic headphones and homebrew rigs and repros and other stuff to use them with.  You can ask if you are looking for something special.  Visit his headphone heaven and get some serious headphones.  Now has some nice drawings of the Heathkit CR 1.  Learn how to mount your galena crystals.
*Larry's Genuine "Rockstand" Detector   Handcrafted with cheap American labor; his (he subsidizes these by keeping a day job).  If you get one any place else, you're probably paying too much for too little. Larry used one of these in the dx contest to clean out the state of California, western Canada and half the Baja peninsula.  Includes an assortment of rocks with it for experimenting.(I have one)
*The Xtal Set Societyserious kits (at good prices) and some parts, including new 365 pF air variables, both single and double ganged (very nice ones - smooth and actually 20 - 400 pF).    Also carries  a one-tube regenny kit, designed by Mike Peebles.  Carries a Rocket Radio - nostalgia buffs will like this one.
*Mouser      - get the catalog sent to you; hard to use the online PDF version- best buy for enameled wire - lots of parts and service good - get your crystal earphones here too when you need lots of 'em.  Detailed specs for many parts available on line.
*Dan's Small Parts and Kits - Online catalog, something new all the time; has lots of neat  buys in quantity.  Stock changes, so keep checking back. Good prices and service.
*Playthings Of Past has some nice old stuff, and the prices are very good.  Give Gary a try; you won't be disappointed.
 *Peeble's Originals has some really neat old stuff, with more to come on this site.
*Borden Radio Company  Lance has a nice collection of reprints of articles he has published, and some nice little kits, including a one-tube regenny.  Will also sell you an original rocket radio or a new one.
*Antique Electronic Supply Online - kits and hard to find parts.
*Transtronics - Has a nice basic solderless xtal set by Techtronics  similar to  the older Radio shack version- check out companion solderless speaker/amp.   Has some other neat looking radio/electronics stuff, such as an inexpensive rf signal generator kit.  Minimum $20.00 order.  Buy a bunch of the xtal sets and hand 'em out to every 10 year old in your neighborhood.  See my review of this one.
Dave Schmarder's  Homemade Crystal Radios.  Also has some parts.  Tube sets coming.
John Hern at the Happy Greyhound Has some nice parts you might use.
All Electronics Corp. Has the Techtronics kit for a good price.
Radio Shack -  - best local buy  for small parts, such as  resistors, and plastic coated wire.  Forget the solderless radio kits (okay, get the xtal set and do my project).  Their gazillion and one electronic kits are useful for breadboarding.  Will special order the high impedance crystal earlugs that come with the project kits; best price if you only need one or two; part no. is 10637379.  If you aren't satisfied, no-hassle returns.
PV Scientific Instrument's Crystal Radio Page   - hand crafted radios and kits - they may look pricey, but sets like these aren't junk box specials, unless you have a really nice junk box. Will also make you up a kit - just give them a price range.  If you buy one of their sets and don't like it, send it to me for disposal and I will pay S&H - hi.
Crystal radios built to order      Roger, K8CIX makes some beauties.
Circuit Specialists  electronic parts. Online catalog.
Electronic Kits for Kids   Mini Labs Slider
Ramsey Electronics   has a crystal radio -looks pricey, but worth a try.  Construction and operating manual downloadable in PDF format.
Einstein's Emporium   has the Smithsonian kit and the Mini Labs kit.
Electronic Goldmine has an interesting assortment of electronics stuff, including AM tuning coils and polyfilm variables.  Online pdf catalog.  Good service, and will actually send a cash refund if out of stock on prepaid orders.  Stock rotates.
eBay Listings: Radio Equipment auctions on neat radio stuff.
Ocean State Electronics a nice on-line catalog.  Has some ZN414s (pricey).  Good selection of air variables.
radiokits A "credit card" radio, limited edition (instant classic?)  By Fran Golden - circuit design probably like the new RS kit, but costs more.  Novelty design..
AM Crystal Radio Kit C. Crane imported an interesting  looking slider from Old Blighty.  Another instant classic attempt?  May be a nice gift if you have more money than time.
Dick Smith Electronics  -Australia's answer to Radio Shack - back of catalog has a nice electronics reference section.
Brian Smith's Wireless Workshop A place to go down under when Dick doesn't have it.
Amidon get your ferrite cores and toroids from the source. buying info: Crystal Radio Kit   a Minilabs slider at a good price
"NOVICE" Crystal Set another xtal set from "over there"
MINI LABS CRYSTAL RADIO . And yet another source
Circuit Test Electronics another set from the UK
C.B. Schrock It took two years, but they got their picture links working  
Fair Radio Sales Company Inc. surplus and some nice matching transformers for high level detection.
Electronix Express good online catalog.  Still lists the polyfilm variable capacitors.
ONE CHIP AM RADIO KIT a MK484 IC radio.  Looks good, price looks right, but oh, those Canadian shipping charges.  Buy several for your scout troop and amortise the shipping costs around.
Modules & Hard-to-Get Items from  has the MK 484 Chip and the polyfilm varicaps with knobs for good prices offers a fairly pricey looking basic slider
American Microsemiconductor still makes and sells germanium diodes
Vectronics.Com Their crystal set; pricier than it ought to be for a simple set
MFJEnterprises.Com  has a dip meter for sale.
Alfa Electronics-DM-4061A Grid Dip Meter Classifieds - Search for used test equipment
Phil Seltzer Online Toy Catalog buy a set similar to the  current RS kit in bulk - the minimum order is a bit high, and I can't say what the set's like, but the price is reasonable.
C & S Sales -- Product Detail has a Maxitronix set similar to the current Radio Shack version.  Watch out for the earplug (see my review of their 901 kit).
Micro-Mark   here is some low melting point metal for mounting rocks
CRYSTAL RADIO   Buy the Smithsonian set in Mexico - oooh, those prices!
Pete's Electronics Pete is in the UK and has an eclectic set of interests and some parts you might be looking for, including germanium transistors.
Brainywires  A crystal set with transistor amp assembled with magnets?

Since I have been mostly been building my own, or helping students with theirs, I can't say how most of the kits will work out, but will put up a new page and post  reviews if you send them to me.


*The Xtal Set Society - get a sample copy of their newsletter on line, then subscribe.  I've got 8 of their books, and am getting more.  Be sure to include P.A. Kinzie's book on Crystal Set History, Fundamentals and Design in your order.
The National Radio Club / DX Audio Service - has  useful publications and reprints on dxing, antennas, crystal sets...Get Ray Cole's "The Challenging Crystal Set" and a reprint of Mike Tuggle's original Lyonodyne receiver article.
*Lindsay Publications      fun to read web site and catalog.  Good service.
Bequaert Old Books formerly Rainy Day books, which is now the other Rainy Day Books... aw heck, just go there for some interesting early radio reprints Search for New, Out of Print and Used Books - the world's largest source of out-of-print books!
Nation Builder Books
Books and Videos on Transistor Radios and More worth a look for collectors
ManualMan Homepage large selection of electronic operating, service and assembly manuals
RADIO MANUAL CATALOG for Heathkit, HP, Johnson, Icom, JVC, KDK, and Kenwood radio's
The Official "Voice Of The Crystal" Web Page author's preview of the book
Home to Babani Books  UK publisher
WRTH | The Directory of International Broadcasting  
Electronic Vacuum Tube Reference Manual & Specifications on-line; many sections of the book.


 Collecting, collections, nostalgia and related groups

Gasoline Alley Antiques NOVELTY RADIOS has some original Miniman rocket radios - very pricey, but some people will spend anything on nostalgia.
Welcome to - offers some of the small radios of yesteryear as collectors items.  Take a look and bring your checkbook.
GOLLUM has some neat pix at his site too.
Antique Radio Classified: Radio on the Web order sample copy of the magazine on line; you might get hooked
Antique Radio Resources   links page to a lot of antique radio sites, including some pix of early crystal radios.
Radiomuseum Rottenburg pix of some nice old crystal sets
Radios Antigos no Brasil a nice page from Brazil, in english
Radio and Phono Archives
Peter's Radio-Page
Matt's antique radio page
ancient radios
AGN another beautiful set
 NIST SP 958 - A Century of Excellence in Measurements, Standards, and Technology Download a monograph on the little NBS simple receiving set.
Xtal Radio Index Japaanese site with some nice pix
Misc crystal sets some nice old radios
Antique Wireless Association
Pre-1930 has some old sets and some interesting repros.
LWCA Longwave Home Page when you're ready to go down low....
Natural Radio and when you want to really go low, go here (might need an amp)
Pickard, Greenleaf Whittier :  some biographical notes on the crystal detector's inventor
Virginia City Radio Museum
Radio Operations Aboard Submarines .  Not a darn thing to do with xtal sets, but oh, the memories...this fellow's last sub, USS Amberjack was the first one I served aboard
Antique Wireless And Scientific Instruments
No. 176: Crystal Sets let John Lienhard at the University of Houston take you back to the joys of being 9.  Link to a rare Sears xtal set ad as well. When you get to the bottom of the page, go to the rest of the series; marvelous reading. This is a later version of the episode:  read them both No. 1695:  Crystal Set
Antiques of Science & Technology  
toy crystal radios, germanium diode radios Some pix of "toy" crystal sets.
Lorne's Vintage Wireless Homepage
American Radio Relay League   The A#1 organization for Hams.  Use this site to check out the ham fests and swap meets near you.
John Jenkins Vintage Radio a collection of beautiful US and european sets.
Hammond Museum of Radio
Fessenden and the Early History of Radio Science
Papa's War Part 1 not exactly on the mark, but a good read
Transcripts of The Engines of Our Ingenuity the rest of John Leinhard's articles.  Must reading.
Radios  crystal radios from the 50's and 60's.  Bring your checkbook.
Braun   short bio of one of the other crystal set inventors
Crystal radio   Some old xtal sets from a Belgian site
Rocket Radio   another rocket radio remembrance  marconicalling  digital archives from the UK
Ediswan 1923 an early xtal set
United States Early Radio History

Rockheads in (Cyber)Space

thecrystalsetradioclub -Cyberspace crystal radio club; bandwidth courtesy of Yahoo.  Join in and connect with other rockheads.  Anyone can watch, or join in.  Lively postings and good stuff. (Got to join to see the pictures) This is a closed group, but email me and I'll get you an invite; same with the next group.
 ferritecore The original xtal set forum - went unlisted by mistake, but see ferrite 61 in the club above for an invite in
*Rap 'n Tap Discussion Group   the updated Xtal Set Society forum.   An excellent place to get in on the action - visitors positively welcome.  A mailing list/discussion group.  Just log in and send your traffic.
crystal swap - a place to exchange and swap parts - get on the Crystal Set Radio club and ask Skywave_99 for an invite in. (unlisted)
Yahoo! Groups : crystalradiothinktank     -Recently transitioned from clubs.   Okay to get off topic.
crystalsetradioclubarchive just a storage place
Yahoo! Groups : amradiodx  
Yahoo! Clubs homebrewtransistorradios
Yahoo! Groups : RookCoils
Yahoo! Clubs homebuilttuberadios  
Yahoo! Groups : vintagextalradioplans
Yahoo! Groups : amradiodx
Yahoo! Groups : CrystalRadio