Re: [avr-chat] Sample program for ATmeGA128RFA1

[Joerg Wunsch]

David VanHorn <address@hidden> wrote:

> We failed emissions by a large margin, and when we went looking for
> problems, found that the antenna impedance was way off.

Ah, I see.  The problem here is that these baluns are no baluns in the
classical sense (magnetically coupled transformers) but lumped LC
circuitry that behaves *as if* it were a balun.  However, this
behaviour will only work if they are operated on their design
frequency, and loaded with their design impedance.  For anything else,
both the balun function and obviously also the filter function
suffer.

(Magnetically coupled baluns can easily span an order of magitude in
their frequency range, and they will simply transform any impedancy
mismatch to the other side of the balun.)

-- 
cheers, Joerg               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)