Date: Sun, 26 Mar 2017 16:22:58 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: Rfi List <rfi@contesting.com>, towertalk reflector
<towertalk@contesting.com>
Subject: [TowerTalk] New Larger Fair-Rite #31 Toroid
KY8D asked me about a new, larger #31 toroid that has recently been
added to the catalog. It's 4-in o.d., 3-in i.d, and 1-inch long.
http://www.fair-rite.com/product/round-cable-emi-suppression-cores-2631814002/
Note the impedance data for 1, 3, and 5 turns at the bottom of the page.
Gan's email arrived today (Sunday) so I haven't had the opportunity yet
to investigate pricing. My guess is at least double the cost of the
2.4-in toroid, but because it's twice the length (1-in as opposed to
0.5-in for the 2.4-in toroid), a single core will likely be equivalent
to two of the 2.4-in cores, so fewer cores will be required to achieve
the same choking Z. More important, the much larger i.d. will allow more
turns and/or larger coax.
73, Jim K9YC
## I saw the new 4 inch OD x 3 inch ID x 1 inch long type 31 torroid on
their
site over a year ago, I believe its been there for quite some time. If you
look at the
impedance data for 1,3,5 turns, at various freqs, you will see that the new
bigger torroid
has just a hair higher results when you rapidly toggle between the 2 x cores.
Unless you are
hell bent trying to stuff more than 7 turns of RG-393 or RG-213 through a
torroid, IMO, the
bigger 4 inch OD torroid really buys you nothing..and its twice the length to
boot. Its also 2.5
x heavier. 420g vs 117g.
## Danny, E73M, and myself looked at the new 4 inch OD torroid, and
discarded it soon after.
The ID is simply too big, being a whopping 3 inch ID, so even though its twice
the length of the
smaller 2.4 inch OD x 1.4 inch ID, it buys you nothing when you measure both
of the torroids,
with 1-7 turns of 393 or 213 . The smaller torrid is only half the length,
and works 99% as good.
If you say had a requirement for 6 x 2.4 inch cores... = 3 inches long.....
you would require 5 x 4.0
inch cores to do the same thing..... = 5 inches long.
## The bigger 4 inch core would be ideal if trying to wind flexible power
cable around it..or something
like LMR-600UF etc.
Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|