[RFI] shopping for toroids

Pierfrancesco Caci pf at tippete.net
Sun Dec 1 13:33:57 EST 2013

I'm trying to come up with a shopping list for assorted toroids for RFI
suppression. At the moment, I can identify these needs:

- a choke for a 80-40 m dipole. I'd like to make this by passing
  rg213-like cable through the biggest 31 material cores. Fair-rite
  2631814002 should be the one, and I think I'll need 5. I'm pretty sure
  this is overkill (I have 100W, and can go up to 500 maybe one day), so
  maybe 2631803802 used with rg58-like cables is a better choice?

- an assortment of tubular (for cables I can solder myself) and clamp-on
  cores (for when I can't cut, think USB cables and such) for reducing
  RFI from assorted equipment. In choosing the internal diameter, should
  I go for the "easy" fit, or for the tight one? Think e.g. rg58 cable
  that is 5 mm diameter, there are cores at 4.95 mm and other that are
  6.35 mm. Same for rg213, which is 10 mm, and cores are available as
  9.50, 10.15, 12.80 mm. 

For applications above 20 MHz but still under 200, is there any reason
to prefer material 31 over the slightly cheaper 43? The graphs on Jim's 
RFI-Ham and the data on Fair-rite site seem to say 43 is as good, am I
missing something? 

Where do my fellow Europeans get their supplies from? I'm looking at
Mouser, as Farnell redirects me to the .it site that only sells to
businesses with VAT number. 



Pierfrancesco Caci, ik5pvx

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