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Low-loss toroids
Hi all,
I've been trawling through my various catalogues tonight looking for toroids that might be suitable to wind hi-Q inductors around, but am disappointed to see that all the stuff on offer seems to be geared around interference suppression and is consequently - I assume - very lossy material. Does anyone know of a source in the UK that can supply small, *low-loss* toroids by the dozen to the hobbyist via mail order? Thanks, p. -- The BBC: Licensed at public expense to spread lies. |
Paul,
You need to look at powdered iron cores instead of ferrites. K5HJ "Paul Burridge" wrote in message ... Hi all, I've been trawling through my various catalogues tonight looking for toroids that might be suitable to wind hi-Q inductors around, but am disappointed to see that all the stuff on offer seems to be geared around interference suppression and is consequently - I assume - very lossy material. Does anyone know of a source in the UK that can supply small, *low-loss* toroids by the dozen to the hobbyist via mail order? Thanks, p. -- The BBC: Licensed at public expense to spread lies. |
Paul,
You need to look at powdered iron cores instead of ferrites. K5HJ "Paul Burridge" wrote in message ... Hi all, I've been trawling through my various catalogues tonight looking for toroids that might be suitable to wind hi-Q inductors around, but am disappointed to see that all the stuff on offer seems to be geared around interference suppression and is consequently - I assume - very lossy material. Does anyone know of a source in the UK that can supply small, *low-loss* toroids by the dozen to the hobbyist via mail order? Thanks, p. -- The BBC: Licensed at public expense to spread lies. |
Yes, powdered iron (I believe it's "iron dust" in the Queen's English)
is what you want. The major manufacturer of suitable cores is Micrometals. Their products are sold by Amidon and others. Give their web site a look for general info, and a google search should yield some retail sources. For HF work, type 6 generally gives the highest Q, with type 2 in second place. Roy Lewallen, W7EL Charles R. Ott wrote: Paul, You need to look at powdered iron cores instead of ferrites. K5HJ |
Yes, powdered iron (I believe it's "iron dust" in the Queen's English)
is what you want. The major manufacturer of suitable cores is Micrometals. Their products are sold by Amidon and others. Give their web site a look for general info, and a google search should yield some retail sources. For HF work, type 6 generally gives the highest Q, with type 2 in second place. Roy Lewallen, W7EL Charles R. Ott wrote: Paul, You need to look at powdered iron cores instead of ferrites. K5HJ |
In article , Roy Lewallen
writes: Yes, powdered iron (I believe it's "iron dust" in the Queen's English) is what you want. The major manufacturer of suitable cores is Micrometals. Their products are sold by Amidon and others. Give their web site a look for general info, and a google search should yield some retail sources. For HF work, type 6 generally gives the highest Q, with type 2 in second place. Quite so, Roy! Micrometals website is - http://www.micrometals.com The website has a nice, free, downloadable program for calculating the number of turns for any of their toroidal cores for any of their powder mixes for many sizes of magnet wire. One of their publications is the venerable "Q Book" which graphs the Q of many different inductances wound on their forms over frequency from LF to UHF. If Paul can talk them out of a copy he will find it indispensable for estimating toroidal inductors... provided there is a supplier on his side of the pond. Amidon is a reseller (Micrometals' minimum order is at least 100 of any type, or was). Most of the small quantities found in ham and electronics stores here have some typical Q curves enclosed in the plastic packet, curves originally from Micrometals. Len Anderson retired (from regular hours) electronic engineer person |
In article , Roy Lewallen
writes: Yes, powdered iron (I believe it's "iron dust" in the Queen's English) is what you want. The major manufacturer of suitable cores is Micrometals. Their products are sold by Amidon and others. Give their web site a look for general info, and a google search should yield some retail sources. For HF work, type 6 generally gives the highest Q, with type 2 in second place. Quite so, Roy! Micrometals website is - http://www.micrometals.com The website has a nice, free, downloadable program for calculating the number of turns for any of their toroidal cores for any of their powder mixes for many sizes of magnet wire. One of their publications is the venerable "Q Book" which graphs the Q of many different inductances wound on their forms over frequency from LF to UHF. If Paul can talk them out of a copy he will find it indispensable for estimating toroidal inductors... provided there is a supplier on his side of the pond. Amidon is a reseller (Micrometals' minimum order is at least 100 of any type, or was). Most of the small quantities found in ham and electronics stores here have some typical Q curves enclosed in the plastic packet, curves originally from Micrometals. Len Anderson retired (from regular hours) electronic engineer person |
"Paul Burridge" wrote in message ... Hi all, I've been trawling through my various catalogues tonight looking for toroids that might be suitable to wind hi-Q inductors around, but am disappointed to see that all the stuff on offer seems to be geared around interference suppression and is consequently - I assume - very lossy material. Does anyone know of a source in the UK that can supply small, *low-loss* toroids by the dozen to the hobbyist via mail order? http://www.sycomcomp.co.uk/ Leon |
"Paul Burridge" wrote in message ... Hi all, I've been trawling through my various catalogues tonight looking for toroids that might be suitable to wind hi-Q inductors around, but am disappointed to see that all the stuff on offer seems to be geared around interference suppression and is consequently - I assume - very lossy material. Does anyone know of a source in the UK that can supply small, *low-loss* toroids by the dozen to the hobbyist via mail order? http://www.sycomcomp.co.uk/ Leon |
For years Amidon was pretty much the only place hams bought ferrite and
powdered iron cores. A different company sprang up a few years back, composed of some former Amidon associates as well as former Amidon employees, and they are selling the same things. (Their reasons for going out on their own involves, I believe, discontent with their relationships with their former company, something which is hardly uncommon in the business world.) The name is Bytemark, or more properly CWS Bytemark, since it merged with CWS a while back. The URL is http://www.bytemark.com/ and the site has a lot of technical info on the toroids. At least one of them is a ham, Tracy Markham, N4LGH, who was the driving force behind the original Bytemark. He's a homebrewer and was active on the QRP mail reflector for a few years. |
For years Amidon was pretty much the only place hams bought ferrite and
powdered iron cores. A different company sprang up a few years back, composed of some former Amidon associates as well as former Amidon employees, and they are selling the same things. (Their reasons for going out on their own involves, I believe, discontent with their relationships with their former company, something which is hardly uncommon in the business world.) The name is Bytemark, or more properly CWS Bytemark, since it merged with CWS a while back. The URL is http://www.bytemark.com/ and the site has a lot of technical info on the toroids. At least one of them is a ham, Tracy Markham, N4LGH, who was the driving force behind the original Bytemark. He's a homebrewer and was active on the QRP mail reflector for a few years. |
On Mon, 22 Mar 2004 08:18:56 -0500, "Mike Czuhajewski"
wrote: Useful site! I've gleaned some handy formulae from it, but since they're an American outfit, I've actually ordered via the company Leon kindly pointed me to. Thanks all. -- The BBC: Licensed at public expense to spread lies. |
On Mon, 22 Mar 2004 08:18:56 -0500, "Mike Czuhajewski"
wrote: Useful site! I've gleaned some handy formulae from it, but since they're an American outfit, I've actually ordered via the company Leon kindly pointed me to. Thanks all. -- The BBC: Licensed at public expense to spread lies. |
In article , "Mike Czuhajewski"
writes: For years Amidon was pretty much the only place hams bought ferrite and powdered iron cores. A different company sprang up a few years back, composed of some former Amidon associates as well as former Amidon employees, and they are selling the same things. (Their reasons for going out on their own involves, I believe, discontent with their relationships with their former company, something which is hardly uncommon in the business world.) The name is Bytemark, or more properly CWS Bytemark, since it merged with CWS a while back. The URL is http://www.bytemark.com/ and the site has a lot of technical info on the toroids. At least one of them is a ham, Tracy Markham, N4LGH, who was the driving force behind the original Bytemark. He's a homebrewer and was active on the QRP mail reflector for a few years. Amidon Associates started up in Burbank, CA, in 1963 as a small business by Bill Amidon, then with NBC at the NBC western Hq complex in Burbank. The product was small-quantity reselling of Micrometals powdered-iron and Fair-Rite ferrite products, packed one to a few in small plastic bags found on display racks in hobby electronics stores. Micrometals was begun in 1951 in Orange County (just south of Los Angeles County that includes Burbank). Micrometals is a powdered-iron product manufacturer who sells in large minimum quantities. Micrometals is also the origin of the Q curves (found in limited quantity in Amidon packets) and the part number format that so many now associate with Amidon. Micrometals doesn't sell directly to hobbyists (unless they order a minimum quantity) but Amidon Associates did/does. Amidon reselling was and is a good service for hobbyists. It is my understanding (but no proof) that Bill Amidon was a ham. His name doesn't appear on a QRZ search. For a part-time business started 40 years ago, Amidon Associates changed addresses a couple times and seems to have been purchased by another group and turned into "Amidon Corporation." That company has a website at http://www.amidoncorp.com and you can find many, many Q curves (good for reference) on one of their inernal pages plus a lot of data good for planning powdered-iron toroid or ferrite applications. Amidon Corporation is headquartered in Costa Mesa, CA, and claims it has "manufacturing" (probably like a lot of distributors claim pseudo-ownership of the companies on their product card). They will sell small quantities of forms, wire, 3M tapes, teflon tubing, the older Amidon Associated kits, etc., and have an 800 number listed "for hams." Yes, CWS Bytemark exists also, headquartered in Santa Ana, CA. [all the powdered-iron companies have gravitated to Orange County? :-) ] Under the "Parent Company" there, it comes out that Coil Winding Specialists owns them and deals or resells a number of frequency products, some of them from Asian manufacturing locations. I'm not going to delve into "business practices." Such doesn't have any bearing on "Low Loss Toroids." I do know that Amidon Associates had a very handy and useful service for hobbyists (myself included) in reselling Micrometals products. I do know that Micrometals has a quality product after specifying orders from them at work. The original Micrometals toroidal form ID format has now assumed a "Texas Instrument" kind of status in that many others use their same nomenclature...like "7400" is a quad 2-input NAND logic IC package identifier to all regardless of who actually made it. :-) Len Anderson retired (from regular hours) electronic engineer person |
In article , "Mike Czuhajewski"
writes: For years Amidon was pretty much the only place hams bought ferrite and powdered iron cores. A different company sprang up a few years back, composed of some former Amidon associates as well as former Amidon employees, and they are selling the same things. (Their reasons for going out on their own involves, I believe, discontent with their relationships with their former company, something which is hardly uncommon in the business world.) The name is Bytemark, or more properly CWS Bytemark, since it merged with CWS a while back. The URL is http://www.bytemark.com/ and the site has a lot of technical info on the toroids. At least one of them is a ham, Tracy Markham, N4LGH, who was the driving force behind the original Bytemark. He's a homebrewer and was active on the QRP mail reflector for a few years. Amidon Associates started up in Burbank, CA, in 1963 as a small business by Bill Amidon, then with NBC at the NBC western Hq complex in Burbank. The product was small-quantity reselling of Micrometals powdered-iron and Fair-Rite ferrite products, packed one to a few in small plastic bags found on display racks in hobby electronics stores. Micrometals was begun in 1951 in Orange County (just south of Los Angeles County that includes Burbank). Micrometals is a powdered-iron product manufacturer who sells in large minimum quantities. Micrometals is also the origin of the Q curves (found in limited quantity in Amidon packets) and the part number format that so many now associate with Amidon. Micrometals doesn't sell directly to hobbyists (unless they order a minimum quantity) but Amidon Associates did/does. Amidon reselling was and is a good service for hobbyists. It is my understanding (but no proof) that Bill Amidon was a ham. His name doesn't appear on a QRZ search. For a part-time business started 40 years ago, Amidon Associates changed addresses a couple times and seems to have been purchased by another group and turned into "Amidon Corporation." That company has a website at http://www.amidoncorp.com and you can find many, many Q curves (good for reference) on one of their inernal pages plus a lot of data good for planning powdered-iron toroid or ferrite applications. Amidon Corporation is headquartered in Costa Mesa, CA, and claims it has "manufacturing" (probably like a lot of distributors claim pseudo-ownership of the companies on their product card). They will sell small quantities of forms, wire, 3M tapes, teflon tubing, the older Amidon Associated kits, etc., and have an 800 number listed "for hams." Yes, CWS Bytemark exists also, headquartered in Santa Ana, CA. [all the powdered-iron companies have gravitated to Orange County? :-) ] Under the "Parent Company" there, it comes out that Coil Winding Specialists owns them and deals or resells a number of frequency products, some of them from Asian manufacturing locations. I'm not going to delve into "business practices." Such doesn't have any bearing on "Low Loss Toroids." I do know that Amidon Associates had a very handy and useful service for hobbyists (myself included) in reselling Micrometals products. I do know that Micrometals has a quality product after specifying orders from them at work. The original Micrometals toroidal form ID format has now assumed a "Texas Instrument" kind of status in that many others use their same nomenclature...like "7400" is a quad 2-input NAND logic IC package identifier to all regardless of who actually made it. :-) Len Anderson retired (from regular hours) electronic engineer person |
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