I've mostly used 73 mix tubular and binocular Fair-Rite cores of all sorts of common-mode chokes on coax and for matching transformers 160/80m receiving loops and for input match to my 3-500ZG amp. Have had good results all around I used 73 because it's what I had on hand. Fair-Rite 73 material is really rugged and seems be very resistant to corrosion etc.
73, Charlie, K4OTV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Tim Shoppa Sent: Wednesday, August 06, 2014 12:45 PM To: Ron Stordahl, AE5E Cc: [email protected]; [email protected] Subject: Re: Topband: Ferrite Cores #31 is a very nice mix for winding chokes especially at topband and lower HF and for EMI suppression. #61 is very common for HF transformers up to medium power levels. #43 is also useful at HF transformers and chokes especially at upper HF. #73 is a very nice mix for low band transformers but some of the testing done shows typical transformers to be good 5kHz-50MHz: http://www.cliftonlaboratories.com/imd_in_broadband_transformers.htm I have been using #73 binocular cores for all sorts of things lately. A little Fair-Rite 2873000202 core works excellently in isolated DC-to-DC power converters at the several watt power level. On Wed, Aug 6, 2014 at 11:15 AM, Ron Stordahl, AE5E via Topband < [email protected]> wrote: > In this discussion two different ferrite mixes are mentioned: #31 and > #61. > > > From the descriptions of these on the Fair-Rite web page, it appears > that > 31 would be more suitable for lower frequency applications. > > > Is this the case? > > Ron, AE5E > > > > On Wednesday, August 6, 2014 4:02 AM, Charlie < > [email protected]> wrote: > > > > I agree with all those points, Jim! Over the years, professionally, we > designed many Fair-Rite, cores into most of our electricity, gas and > water meter and electricity load-management products and shipped > millions of Fair-Rite products in our devices. Fair-Rite and Kreger > are excellent suppliers, and I still have many of their development kits around here. > Their products are excellent and very consistent > > Lynne Frye, of Kreger, is a very helpful contact person, that I have > worked with over the years! > > Have a good day! > > 73, > Charlie Cunningham, K4OTV > > > > -----Original Message----- > From: Topband [mailto:[email protected]] On Behalf Of Jim > Brown > Sent: Tuesday, August 05, 2014 3:00 PM > To: [email protected] > Subject: Re: Topband: Ferrite Cores > > On 8/5/2014 11:36 AM, Mike Waters wrote: > > FT-240-61 cores. Amidon was $9/ea, Mouser (for the Fair Rite > > equivalent) > > >was $14/ea. > > The actual manufacturer of a 2.4-in o.d. #61 toroid IS Fair-Rite. It > is not an "equivalent," #61 material is Fair-Rite's mix. Other > companies may make a "knock-off," but the REAL part is made by > Fair-Rite. > > 73, Jim K9YC > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > > > --- > This email is free from viruses and malware because avast! Antivirus > protection is active. > http://www.avast.com > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _________________ Topband Reflector Archives - http://www.contesting.com/_topband
