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Old April 23rd 08, 02:50 AM posted to rec.radio.amateur.antenna
J. Mc Laughlin J. Mc Laughlin is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 172
Default Use of type 31 ferrite as coax common mode choke

Dear Ian (also my father's name): Thank you for your note. It is a
mystery to me why those who sell via the Internet do not work hard at
keeping their sites up-to-date. 73, Mac N8TT

--
J. McLaughlin; Michigan, USA
Home:
"Ian White GM3SEK" wrote in message
...
Roy Lewallen wrote:

A fairly brief look at the graphs (Figs. 6 - 8) shows that type 31 has
roughly the same or a little higher total complex permeability than 73
over most of the lower HF range and same or higher than 43 on up to 100
MHz. So it should be a good ferrite to use for very wide band
applications. However, Table 1 shows that it's available in large parts
only. Type 43 is very widely available in a wide variety of sizes, so you
might have a lot more luck getting cores of the sizes you need in type 43.

Roy Lewallen, W7EL



Amidon do stock some type 31 products, including FT-240-31 toroids and the
large beads for RG213, but they aren't listed on the website.

Part numbering is the same as normal, so simply substitute a "31" in the
part number you wish to order, and then call 1-800-898-1883.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek