Ferrite Bead Research Results

[KWIDELITZ at delphi.com]

A few weeks ago there was a thread relating to ferrite beads. Since I keep
having RF problems pop up just when I think I've solved them all, and since
I have spent a considerable sum on Radio Shack Snap-on ferrite chokes, and
since it seems common knowledge (but previously unknown to me) that they
aren't the best product, I was very interested in the posts.

It seems the 77 material is better suited for HF than the 43 material, but
my research, consisting of calling a lot of distributors and manufacturers,
has led me to find that no one makes a split bead in 77 material. An
engineer at Fair-Rite claims the 77 material's properties change in a larger
bead (.25/.5 i.d.,) but Amidon's engineer claims they have superior
technology and their beads do not have property changes in the .25/.5 i.d.
size. However, there was no explanation for why Amidon does not offer the
.25/.5 i.d. in 77 material in a split bead.

However, they will cut those beads in half and the engineer says you could
just tape the halves and the loss of ferrite in the cutting process would be
minimal as they would use a diamond saw. Preliminary negotiations have led me
to believe that with a reasonable quantity (between 500 and 1000 pieces) the
price on the .5 i.d. 77 material split bead would be about $2.25 each.
Compare that to the $6.04 single piece price for the 43 material split bead
(which comes with a plastic case for snapping shut.) The .25 split bead
would be about $.40 less. I don't know if the case for the 43 material could
be used with the 77 material as the bead size is a little different, but I
will check.

I am willing to front this custom order and cutting job if there is enough
interest from others to co-op the purchase. I will resell them at cost, but
only in larger quantities. I don't want to get into the ferrite bead
business and I sure don't want to ship small quantities. If you are
interested in 50+ pieces, let me know and I'll put an order together. I want
to do this in the next week, so please let me know if you are interested in
the next few days. If you are in the ham business and want to pick this up,
let me know as I think there is a market, and you can have it.

73. Ken, AB6FO, KWIDELITZ at DELPHI.COM

>From 106315.707 at compuserve.com (Ian Buffham)  Sat Oct 12 15:27:13 1996
From: 106315.707 at compuserve.com (Ian Buffham) (Ian Buffham)
Date: Sat, 12 Oct 1996 10:27:13 -0400
Subject: IOTA CONTEST 1996
Message-ID: <199610121027_MC1-AD0-765E at compuserve.com>

Hi Guys, If you you took part in the 1996 IOTA Contest from an Island and
you have an interesting story to tell we are looking for material for the
1996 results booklet. Also any photographs would be very welcome. The
deadline for material is 21 November 1996. My address is Fir Tree House,
Northgate, West Pinchbeck, Spalding, Lincs PE11 3TB, England. or by
Internet or fax +44 1775 640711. Best regards
Ian Buffham G3TMA RSGB IOTA Contest Co-ordinator.

>From jayt at comtch.iea.com (Jay Townsend)  Sat Oct 12 17:13:19 1996
From: jayt at comtch.iea.com (Jay Townsend) (Jay Townsend)
Date: Sat, 12 Oct 1996 09:13:19 -0700 (PDT)
Subject: RTTY list
Message-ID: <199610121613.QAA20614 at comtch.iea.com>

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73 j

-- 
Jay Townsend, WS7I  < jayt at iea.com >