[Elecraft] More Balanced Current Measurements - Voltage Balun

[Jim Brown]

On Thu, 14 Aug 2008 06:37:15 -0500, Phil & Debbie Salas wrote:

>"Heat means LOST POWER. Virtually all baluns like the BL2 use Fair-Rite #61
>(or something quite similar). Download 
>http://audiosystemsgroup.com/RFI-Ham.pdf
>and study Fig 6, the loss characteristics of Fair-Rite #61. The loss begins 
>to rise above 10 MHz, and it isn't pretty above about 20 MHz."

>The figure referred to is using the material as part of an RFI suppression 
>choke where you want attenuation at RF frequencies.  

NO!  The figure shows the FUNDAMENTAL PROPERTIES OF THE MATERIAL as published 
on the data sheet by the manufacturer, Fair-Rite. See the text of the tutorial 
for a discussion of what those data mean. 

>I think you'll find that when the Type 61 material is used as a transformer, 
>it will have very low loss if designed properly. 

That can be a big if. It depends on frequency, the parts used, the windings, 
and the impedances. And as Tom observes, it's not easy to measure with 
instrumentation commonly available to hams. 

73,

Jim Brown K9YC