Re: Crystal CW filter with Version 4 uBITX boards? #ubitx
Exactly how do the transformers ruin this?toggle quoted messageShow quoted text
The uBitx transformers are broadband.
I was imagining somehow holding both filters to 200 ohms, using only one set of transformers.
That might be tough to do and still get the desired filter characteristics.
Though a CW filter may not need such a flat top.
Might be possible to have two sets of transformers in parallel.
The transformers don't have a fixed impedance, they just establish an impedance ratio.
So a high impedance into the filter should mean much higher than 50 ohms into that transformer.
Though all sorts of ways for this to trash performance.
I'd be fine with pluggable filters.
But am curious where dual filters would fail.
As your 45mhz-DialFreq spur shows, things can quickly go south in unexpected ways.
Measurements are useful.
Even if it seems to work.
On Sat, Jul 7, 2018 at 04:51 pm, ajparent1/KB1GMX wrote:
The big difference is the lack of transformers it actually helps for that. That version of the