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- Subject: Re: [IRCA] Matching transformers
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Tue, 23 Dec 2014 23:09:52 -0500
- Delivered-to: irca@xxxxxxxxxxxxxxxx
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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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