[Electronic Eavesdropping Devices Detector]

Is it alright if I don't install into the metal box?....... :-\

Do you have any circuit that can detect the signals up to 108MHz(approximately-like tune radio frequency for FM)

[Electronic Eavesdropping Devices Detector]

if using breadboard rather than pcb, do you think it will work properly?


if using single wire as an antenna, it will pick up the rf signals?

[detector prototype]

the telescopic antenna........is it the antenna used by tuned radio??

[detector prototype]

the component with series BUZ 90A and BUF 90A, is it both same components???..............

[4 bit binary counter]

hello.......anyone can send 2 me logic diagram for 4 bit binary counter, using NAND gate not AND gate...pls..... ;D

[detector prototype]

actually i hold to build the circuit for a while. so, right now i'm doing few experiment and it still related with the circuit. audioguru, i know you are expert in theory, so can you explain this situation clearly?: a hand phone operating at 1800MHz frequencies, a local service provider using the same frequency so the hand phone can receive and transmit the signal to another person. when i put my detector close the hand phone, is it mean that my circuit is detecting noise at the 1800MHz frequencies?

[detector prototype]

i learn that EMI will occur when these three elements exist, source of emission, coupling path and receptor. so, i'm using cell phone as a source of emission and tune radio as a receptor. anyone can explain about the coupling path under this condition?

[detector prototype]

i've few questions here:

1-some cell phones today using dual band and tri band type. is it make any effects on the circuit?
2-in my country(malaysia) we using some types of network: celcom(900MHz), adam(1800MHz),digi(1800MHz),maxis(900MHz) and tm touch(1800MHz), so can you explain how these operating frequencies is working with this circuit?
3-this circuit is operating on the range of 1-1000MHz frequency. then, let say i'm using digi network, could the circuit detect the cell phone?

[detector prototype]

since my project cover in wide scope, then my supervisor want me to design the detector for detecting cellular phone only. nowadays, we find that some places like in hospital, aeroplane even in exam hall(to cheat) and etc. we does not allow to use the phone to avoid any problem. so, my detector suppose to detect when somebody using their phone in that area. as we know when the phone getting close with the radio, we can detect the noise. is it hard to design my hardware using the tune radio circuit or any possible circuit?

audioguru, in this website http://www.electronics-lab.com/projects/rf/005/index.html , can you explain what the number in circle for, and the pin 4 and 11 how to connect it?

[detector prototype]

audioguru, i have look the circuit you suggested before; http://www.electronics-lab.com/projects/rf/005/index.html.

do you have any alternative to use IC

[detector prototype]

i have refer back to my lecturer, he said for switched off electrical appliances, we may need UPS or transformer that have high residual electrical power because my project topic is flexible so it doesn't concentrate to certain device. then now, he want me to try at the beginning stage using mobile phone under this condition (on steadily, on transiently, off steadily and off transiently), so my idea now is using tune radio circuit(am/fm receiver circuit). so after that it can help me to use other appliances and improve my project to get better design. any comments??.......... :)