Topband: Amidon W2FMI UnUn

[George & Marijke Guerin]

Tod, et all.

I did run up and down 160 without SWR issues or changes with both the Amidon 
UnUn and the 2.4 inch diameter 240-61 core UnUn we send with the BCSpecial. 
The bandwidth on 160 was the same with both UnUns.
The website for the Amidon page is:
http://www.amidoncorp.com/aai_cost_ununs.htm
The data sheet says the core is an Amidon PN FT-150-K
The data sheet also says the quadrifaler winding is 4 windings of Four turns 
each #14 formvar SF wire.  The top winding is tapped at 2 turns for the 
extra 50 ohm connection.
The interlace of the 4 turns is such that ground is the bottom of winding 
one, then the top of winding 1 goes to the bottom of winding 4, then to 
winding 2 and then to winding 3 to get a better coupling than just linearly 
connected 1-2-3-4.

I hope this helps.

George    K8GG

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