Posted by
David Woolley (E.L) on
Aug 26, 2010; 8:15pm
URL: http://elecraft.85.s1.nabble.com/BL2-choking-Impedence-measurements-tp4686857p5467089.html
Ian White GM3SEK wrote:
> CUTTER DAVID wrote:
>
> Some UK suppliers do stock beads in #31 material but mostly not the ones
> that interest us. I haven't checked in the past few weeks, but will need
I'm fairly sure that Farnell did some #31 material, bigger than beads,
but smaller than typical for amateur radio use. I seem to remember you
had to read between the manufacturer's catalogue number to work out it
was #31.
> to refresh this information in time for the RSGB Convention.
I tried writing to the RSGB's EMC contact email addresses a few months
ago, enquiring about sources of #31 material (and twisted pair speaker
cables in less than whole drums, although I've found the latter and I'm
waiting to see if it helps). However the first address I tried bounced
and the second one never replied, so I gave up.
I think the big problem is one of education. Most people in the hobby
believe that toroids are good, but probably don't even realise they have
to be ferrite. The RSGB's filter collection doesn't seem to have
changed in a couple of decades, and the big traders, presumably
successfully, sell EMC toroids without any indication of what they are
made from.
>> What is going through my mind is how the amateur fraternity could
>> persuade a distributor in EU to stock these and the type 31 cores.
In terms of the big electronics distributors, you probably have to
convince them that there is a large commercial shortwave RF engineering
industry in the UK, which may not be true any longer. For the amateur
equipment suppliers, you need to educate the market so they refuse to
buy anything else.
--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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