I feel that part of the problem is that the commercially available T
match network ATU in conjunction with a balun is NOT the way to go about
this.
I'm just finishing an ATU for this job, and it's similar to the 80 m ATU
- a parallel tuned circuit, with a tuned link. I'm only using it for
receive, and possibly QRP tx, but the basis is a 500 + 500pF split
stator tuning C, with a 150pF padder (porcelain, rated at 2KVA at 3MHz)
across it, a 4.5 microhenry link winding (in my case, some 1.25 inch
diameter Air Dux or B& W coil stock) inside the tuning coil. The tuning
coil is on a 2 inch ceramic former, is 32 microhenries, wound with #16
AWG, centre tapped. The link is tuned with a 1500pF air variable,
shunted by 1200pF of transmitting grade mica capacitor, rated for 9Amps
at 3MHz.
I expect this to be lower loss than coax.
73
Peter G3RZP
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