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Re: [IRCA] Matching transformers



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K1FZ makes transformers in rugged enclosures.
http://www.qsl.net/k1fz/

There is also Mini-Circuits, though DXers lately have been steering away from them as they don't hold up as well in strong signal areas or where there is harsh weather / frequent thunderstorms.
http://www.minicircuits.com/products/Transformers.shtml

I homebrew my own, as do several other local DXers such as Bruce Conti.

Either binocular (type 73) or toroid (types 75, J) cores work well.

Cores typically used:
Toroid = Amidon FT-114-J or FT-114-75 or FT-140A-J; Steward 35T0501-10H
Binocular = Fair-Rite 2873000202 or Amidon BN-73-202

16:1 (Flag / SuperLoop or Kaz Delta to 50-75 ohm coax.)
48 turns : 12 turns toroid
12 turns : 3 turns binocular

9:1 (Beverage / BOG / sloper to coax.; Flag / SuperLoop or Kaz Delta to 90-150 ohm balanced line)
48 turns : 16 turns toroid
12 turns : 4 turns binocular

4:1 (BOG / sloper to 90-150 ohm balanced line)
32 turns : 16 turns toroid
8 turns : 4 turns binocular

2:1 (90-150 ohm balanced line to coax. / receiver)
17 turns : 12 turns toroid
7 turns : 5 turns binocular

1:1 (coax. to coax.: ground isolation for noise reduction)
12 turns : 12 turns toroid
4 turns : 4 turns binocular

Toroid windings should be overlapped per Figure 3 of John Bryant's article:
http://www.dxing.info/equipment/impedance_matching_bryant.pdf

Mark Connelly, WA1ION
South Yarmouth, Cape Cod, MA

<<
Happy Holidays to everyone,

I have always made my own matching transformers, but I got an e mail from someone who is interesting to buying one. Does Universal or anyone sell one?
Thanks.

Patrick

Patrick Martin
Seaside OR
KGED QSL Manager


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