[RFI] 2.4" OD #31 toroids

[Pete Smith N4ZR]

Does anyone have a source for these?  I can't even find them on the 
Fair-Rite web site any more.  I want to build a couple of super-good 
common-mode chokes of the ON4UN/K9YC-recommended split type with ground 
in between, wound with RG-59, and assume these cores will work fine. 
Also, since this is a receiving application, I assume I can get by with 
a single core to keep the cost and bulk down.  Wrong?

73, Pete N4ZR
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