Hi all

How to calculate the input circuit (C1, C2, L2, L3) for certain frequencies?

Thanks a lot!

 

the standard l/c resonance formulas work fine for that, just remember the 2.8 pf input capacitance.
http://www.discriminator.nl/ic/ta31136.pdf
there is the factrory data sheet.

 

Changing the operating RF frequency of this receiver is A LOT more complicated than just changing the tuned circuit on the input. You need to change the local oscillator frequency, get the expected IF frequency, adjust the LPF and HPF component values at the inverting amp, and change the quadrature detector operating frequency (if you use a different IF -- intermediate frequency).