Re: 2.5 MHz low pass fiilter uses no toroids, SMDs #ubitx

Howard Fidel
 

You made a high pass filter, not low pass.

On 6/10/2018 9:12 PM, Peter Parker wrote:

I've been experimenting with various types of low pass filters to cure BCI. 

My starting point was the VK3IL design. Then I changed the values to use prewound 2.2 uH RF chokes I had.  Increasing the capacitors by a similar factor (approx 1.5 times) dropped the cut-off frequency to around 2.5 MHz.  This may offer somewhat less attenuation of the broadcast band but does mean that the uBitx will tune WWV on 2.5 MHz without too much loss.  Also 160m reception should be possible on stronger signals.  The big benefit (for some) is there's no need to wind your own toroids.  And you can use conventional components on a small circuit board that can be sawn to make the pads.  

I'm pleased with its performance. More in this video. 

https://www.youtube.com/watch?v=fgQenFJOjr4

73, Peter VK3YE

 


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