EMRFD Message Archive 3606
Message Date From Subject 3606 2009-10-09 14:12:32 Stephen Wandling Ferrite tubes, Binocular cores and Ferrite toroids
line, and I have been looking at small loop antennas and wanted to try
this one by G0CWT: http://g0cwt.co.uk/magloops/details.htm
I don't have the ferrite tubes that he used for his matching transformer
and realized that I don't know why one uses such a configuration, or the
binocular core, instead of a ferrite toroid. In fact, I don't know why
ferrite and not powdered iron. Those are my main questions to you here.
I am going to experiment with some ferrite cores I have: FT37-43 and
FT37-61, but I prefer to experiment with some knowledge of what I am doing.
Thanks
Stephen
VE7NSD
[You can see my location on my QRZ map]3607 2009-10-12 00:20:13 Jon Iza Ferrite tubes, Binocular cores and Ferrite toroids
I don't want to open that can of worms, but may I suggest the web page
of Tom W8JI?
http://www.w8ji.com/core_selection.htm
With respect to the lack of ferrite "tubes", you may do it by piling up
regular toroids as Dominique, F1FRV, does on his web page (in French):
http://f1frv.free.fr/main3c_Baluns.html
He uses 2x3 toroids and 2x5 FT140-43 for his high power ones.
BTW, Tom and Dominique have different opinions on the materials to be
used... (I told you, it is a can of worms...)
I hope you will enjoy the reading.
Be well
jon, ea2sn3608 2009-10-12 08:35:29 Tim Ferrite tubes, Binocular cores and Ferrite toroids
> of Tom W8JI?
> http://www.w8ji.com/core_selection.htm
> With respect to the lack of ferrite "tubes", you may do it by piling up
> regular toroids as Dominique, F1FRV, does on his web page (in French):
> http://f1frv.free.fr/main3c_Baluns.html
> He uses 2x3 toroids and 2x5 FT140-43 for his high power ones.
> BTW, Tom and Dominique have different opinions on the materials to be
> used... (I told you, it is a can of worms...)
> I hope you will enjoy the reading.
What I find interesting, is that often "long toroids" are sold as ferrite beads by the big electronics distributors as some kind of EMI suppression core. For example Mouser 623-2643002402 seems to be just a "longer" FT37-43, but is sold as an "EMI shield bead". Other types have multiple holes for multiple turns, something we might call binocular cores except they aren't described that way in the catalogs. I suspect that many of the larger Ferrite beads, e.g. those intended for SVGA cabling, would make excellent cores for medium power transmitters, but decoding the EMI shielding specs back into ferrite core material is made hard by the way they're listed in the catalogs. For old-line manufacturers like Fair-Rite I can usually decode things back to core material but with other manufacturers it's not so easy.
Tim.