Andy Flind MFD.

[Geo]

1K2 in series with 10uF

[abdou2014]

Thank you what's the coupling capacitor value did you use between lm386 and trannsistor of beep generator ?

[abdou2014]

I use 100nf , I believe it is better to convert the audio signal .

[abdou2014]

1K2 in series with 10uF

I tried your values and i have 3.9 V at output .

[Geo]

Thank you what's the coupling capacitor value did you use between lm386 and trannsistor of beep generator ?

100nF

[Geo]

I tried your values and i have 3.9 V at output .

it's ok...

[abdou2014]

i thnk it's better to connect an auther detector with this coupling 100n

[humhum]

Geo , size of my FM Receiver is 50mm X 70mm small PCB (not use TDA7000 ) , in my test
I see that find my garden buried only from Nort and Nort-West way , but this small unit works only when use or mixing with groundet body energy .
About TDA7000 , need fine calibration of correct Frequency and Local OSC , this Freq can't
measure with any unit .

[Geo]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

[Pahom]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

Geo what kind of coil are you talking about, a loop of 14 turns in a place with a 7000 tda or the receiving antenna itself?

[abdou2014]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

No , the second detector is for electric field can you show us a best buzzer circuit to avoid the erratic signals ?

[Geo]

Radio at 100Mhz is for electric field detection??? ... NO
Use a schematic with speaker....

[abdou2014]

Ok 100 Mhz for electric field , so the second must be for magnetic field , but at what frequency ?

[humhum]

I am not sure that one other radio will do better work...... because i am not sure if it will work ok as sniffer. We want a sniffer out of FM band and TDA 7000 do this job very easy.
The main problem is the erratic signals by buzzer. We must keep it far from coil or must draw and construct a new beeper.

Now I will say Yes , Dear Geo , because have other radio type work better for sniffer
(without TDA7000 IC ) .
Also Andreas have in this forum small box (maybe 433Mhz) shniffer for find buried .
Calibration of TDA7000 is very critical fine tuning for buried Frequency .

[abdou2014]

I tried commercial radio and the TDA7000 is better , believe me