"CA3130 operates at a frequency of only 15 MHz."
That is precisely my point......mis-interpretation of data sheets.
15 Mhz is not the operating frequency, it is only the unity gain crossover frequency....google the term.
And the spec sheet shows that would be only true with a compensation capacitor of zero pF...the schematic shows 47 pF, which would lower that value to 4 Mhz.
But even then, let's assume that the CA3130 could indeed work at 15 Mhz.....the phone's carrier frequency is 900 to 3000 Mhz, orders of magnitude higher. It still won't detect anything at the frequencies that a mobile phone is transmitting. It will pick up powerline harmonics, AM and short wave radio, SMPS noise.....but no cell phone transmissions.
Now...C4 is to clean the DC bias applied to the non inverting input. But its value is waaaaaaay too large, 1 uF would be enough.
There are many other mistakes like that.
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"CA3130 operates at a frequency of only 15 MHz."
That is precisely my point......mis-interpretation of data sheets.
15 Mhz is not the operating frequency, it is only the unity gain crossover frequency....google the term.
And the spec sheet shows that would be only true with a compensation capacitor of zero pF...the schematic shows 47 pF, which would lower that value to 4 Mhz.
But even then, let's assume that the CA3130 could indeed work at 15 Mhz.....the phone's carrier frequency is 900 to 3000 Mhz, orders of magnitude higher. It still won't detect anything at the frequencies that a mobile phone is transmitting. It will pick up powerline harmonics, AM and short wave radio, SMPS noise.....but no cell phone transmissions.
Now...C4 is to clean the DC bias applied to the non inverting input. But its value is waaaaaaay too large, 1 uF would be enough.
There are many other mistakes like that.