Output Filter


Richard Pushman
 

Hi;

Quick observation: all output inductors are wound in T30-6 cores.
Using the inductance calculator found at http://toroids.info/T30-6.php I calculated using the winding data found on the http://www.hfsignals.com/index.php/ubitx-circuit-description/ page.
They don't match.

For instance, L20, L21, and L22 are 900 nH in the schematic, but winding data suggests they would be 1300 nH.
When the output power was measured, the resultant curve seems to indicate that the inductors, indeed, appear to be around 1300 nH.  
I have yet to remove one and measure it. 

Also, has anyone replaced the output filter (a "Constant-K" type) with a different design, such as a Bessel or Chebyshev?

Thanks for all the replies,
AA8NH

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