[Elecraft] Balun for KAT2

[Bill Coleman]

On 1/13/02 2:20 PM, Ron D' Eau Claire at rondec@easystreet.com wrote:

>Chas, W1CG, dropped me a
>note that said:
>
>"I have made some and run some efficiency
>tests.  The 13 T on a FT114-43 core is 97% efficient into a balanced 200
>ohm load, and is 90% efficient into a 5:1 SWR.  They are small and use high
>permeability ferrite to get enough inductance to operate at 1.8 mHz with a
>5:1 SWR, (110 uhy).  A lower loss ferrite or powered iron core would have
>lower losses."

The simplest way to reduce losses for high-SWR is to add additional 
cores. This reduces the maximum flux in each core, which reduces losses.

Powdered-iron cores aren't suitable for these types of baluns, except 
perhaps at UHF. They don't have enough permeability to be effective 
without an excessively large number of turns.

Although you are correct, powdered-iron cores can withstand a much higher 
magnetic flux level than can ferrite cores.





Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901