Homemade Detector

[mikebg]

Preamp with Low Cutoff Frequency at PI
Error or Smart Design Solution?

How to calculate capacitance of C24?

A visual analysis in frequency domain shows what happens when the RF section of RX circuit has relative low cutoff frequency. The attached Bode diagrams represent magnitude characteristics (frequency responses) of both target properties creating signal in RX coil

 

[6666]

The power supply for this project is here



http://www.findmall.com/read.php?34,1537000

 

[SMITY3]

Share please PCB. I very much want to build this detector.

 

[6666]

Its made on Vero board

 

[mikebg]

For visual analyzis of the system (target & preamp), I posted spectral response of permeability and conductivity on October 13, 2011 as magnitude functions (magnitude vs. frequency).
Despite this is not an error, it is not enough for spectral description because a function in time domain should be described always by two functions in frequency domain. Here is the phase response of permeability and conductivity. Note that at cutoff fgequency fc, the conductivity makes phase lag 45 deg relative to current in TX coil.
Remains to show spectral response of a preamp having low cutoff frequency.