Thread: FRG7 Mod
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Old 15th Jan 2022, 1:33 pm   #8
orbanp1
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Join Date: Nov 2009
Location: London, Ontario, Canada
Posts: 631
Default Re: FRG7 Mod

Hi Wendy,

Nice work!

Here is a good article about using the TBA120 ICs in NBFM applications:
https://www.g3ynh.info/circuits/TBA120.html

Interesting is your choice of L-C values for the phase-shift network.
According to calculations those values resonate at about 600kHz.
For that inductance to resonate at 455kHz you would need a cap about 815pF.
Is there so much parasitic, internal capacitance there?

Regards, Peter
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