Re: Polyphase board


ajparent1/kb1gmx
 

1800hz, no idea where you get that.

See the plots on the stor page   http://qrp-labs.com/polyphase.html

It mentions to 1800 hz for things like WSPR and other digital modes but
the board does as shown.

1800hz for SSB  would be on the narrow side.  But thats not the intended application
other than incidental.  Tweaking the Polyphase alone likely will not get you what
you want as its mostly GIGO.

The yabut is the 4 caps I mentioned last time and that also colors the bandwidth
as will the output transformers.

So the QDS detector caps C3-6 must be smaller.
Also the bandwidth of the 600ohm transformer will be only as specified if loaded
to 600 ohms, even then there will be significant roll off under 300hz and likely
the high side too.  They are designed to old school hard-copper telephone
bandwidth (not Iphone) is 200hz at the low end is maybe about it.

Allison
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