+++++++++++++++++++ Date: Mon, 03 Jun 2002 07:20:11 -0700 From: Phil Wheeler Organization: Outstanding To: =?windows-1252?Q?Tom_Hammond_N=D8SS?= Cc: Trevor Day , elecraft at mailman.qth.net Subject: Re: [Elecraft] Toroids I'm not sure how universally applicable this info is, but the following=20 web page: http://tritium.fis.unb.br/Fis3Exp/fcim.csdc.com/fcimis/compid/ind/toroid.= html does have some color coding and properties info. It might, at least,=20 give that initial clue re properties of some cores. I have an old=20 Amidon catablog with similar data. 73, Phil Tom Hammond N=D8SS wrote: > Trevor Day, G3ZYY, wrote: > >> With all the talk about toroids and baluns recently I decided to=20 >> rifle through the junk box looking for suitable cores. It appears=20 >> that I have plenty of all shapes and sizes but I have no idea of=20 >> their individual properties. Is there any way of identifying these=20 >> unmarked devices so I can put a few to good use? > > > I agree with Trevor... > > It'd certainly be a GREAT idea if someone would/could come up with a=20 > treatise, in layman's terms, and using (more or less) commonly=20 > available equipment, to allow us to better identify the myriad toroids = > we might have laying around the shack, and for which we have NO CLUE=20 > of their (even approximate) properties. Now THAT would be a worthwhile = > article. ++++++++++++++++++++ Reply-To: "John J. McDonough" From: "John J. McDonough" To: Cc: Subject: Re: [Elecraft] rf torroid Date: Mon, 3 Jun 2002 17:35:02 -0400 The red ones are generally used for the lower HF. Generally for 20 meters and up people use the yellow ones. Of course, it depends on the application. A lot of people prefer the white ones in VFOs because they have a lower temperature coefficient. The red ones are actually good for the whole HF range, but the yellow ones have a little lower inductance per turn, which can make it a little easier to get the right inductance at the higher frequencies where you usually want a lower inductance. The yellow ones also have better temperature stability and perhaps a little better Q. But they don't work below 10 MHz, so for 30 meters and down, people usually use the red ones. 72/73 de WB8RCR http://www.qsl.net/wb8rcr didileydadidah QRP-L #1446 Code Warriors #35 ----- Original Message ----- From: To: Sent: Monday, June 03, 2002 2:50 PM Subject: [Elecraft] rf torroid > Hi, > > I think that the RED circular toroids, are used for the HF range of > frequencies. Correct me if I am wrong. > > Daniel +++++++++++++++++ From: "Albert Heyes" To: "Julian (G4ILO)" , "Elecraft List" Subject: Re: [Elecraft] UK supplier for Amidon toroids Date: Sun, 29 Dec 2002 18:37:13 -0000 Hello Julian www.bowood-electronics.co.uk sales at bowood-electronics.co.uk and also gqrp club sales both advertise ferrites g3mfj at gqrp.com Both advertise in SPRAT the Gqrp mag. The latest mag has a for sale ad on the back page for Kanga Products 73 albert at g3zhe.fsnet.co.uk ----- Original Message ----- From: "Julian (G4ILO)" To: "Elecraft List" Sent: Sunday, December 29, 2002 4:13 PM Subject: [Elecraft] UK supplier for Amidon toroids > I wonder if any of the G members of this reflector can help me locate a > supplier of Amidon toroids in order to make a 4:1 QRP balun for an antenna > experiment. The only supplier I can find who sold these in small quantities > was Kanga Electronics, but their web page informs me that they ceased > trading at the end of October. > > 73 and a Happy New Year, > -- > Julian, G4ILO. (K2 #392) > Homepage: http://www.qsl.net/g4ilo > +++++++++++++++++ From: "Dave" To: "Julian (G4ILO)" Cc: Subject: Re: [Elecraft] UK supplier for Amidon toroids Date: Sun, 29 Dec 2002 21:39:33 -0000 Julian You could try Ferromagnetics, PO Box 577, Mold, Flints, CH7 1AH. They have an advert in the back of the January 2003 Radcom, sadly no phone number, web site or e-mail... I've made "QRP" baluns using all sorts of ferrite, even those found in old PC power supplies and on the wiring within PCs. Make two baluns and connect them "back to back", then try them at 100 Watts or so from 1.8 to 30 MHz into a dummy load. If you get a good SWR and negligible loss, they should be fine for QRP! 73's Dave, G4AON ++++++++++++++++++ Date: Fri, 21 Mar 2003 14:36:18 -0500 (Eastern Standard Time) From: W2AGN Subject: Re: [Elecraft] Boiled toroids To: kevinrock at earthlink.net, elecraft at mailman.qth.net I have always made it a habit to put VFO toroids in the toaster oven at 250 deg for an hour or so before installing. Guess it works, my K1s, K2, Sierra, etc.,don't drift that I can notice. John W2AGN -------Original Message------- From: Kevin Rock Date: Friday, March 21, 2003 02:27:15 PM To: Elecraft Subject: [Elecraft] Boiled toroids In chapter 4, Oscillators and Frequency Synthesizers, of Experimental Methods in RF Design by Wes Hayward, Rick Campbell, and Bob Larkin there is and interesting section on temperature stabilizing inductors. On page 4.7 it mentions a subtle problem of stress built up in the wires as they are wound. W7EL's method of stress relieving the wire is to boil them! I find this book to be most informative and will gradually build some of the circuits when time is available to do so. Just thought I would pass this along to all you toroid winders out there :) Kevin. KD5ONS ++++++++++++++++++