Hi, I have this problem:
I live in a neighborg where some guys use to pass with car stereos
playing music at such a high volume that my windows start
shaking...seriously!....well what I'm looking (I hope it exists) for a
device which can block their radio or car stereo just when they pass
by in front of my house...not that I want to broke their stereos
down...just some kind of "dead spot" for their car stereos to stop
making noise!
I need help and this group seemed to me that could help me...or maybe
not, in any case please let me know if I'm at the wrong place or where
can I find what I'm looking for ... if such a thing exists?
Thanks to all
Despite comments in other posts it IS possible to fix your problem if
he is listening to an FM station.
What u have 2 do is find which radio station he is listening to, and
broadcast him a stronger signal that his receiver will lock onto in
preference to the radio station. so long as u use a directional
antenna aimed at the car, then none of your side neighbours need be
affected.
To fully automate the proceedure is going to be expensive though.
Have an FM receiver that can scan the band on computer command. Store
the received audio in your computer with both time and frequency
information. Have a microphone listening to the offending car. Once it
is determined that the volume is exessive your radio receiver scans
the band and compares the audio from the microphone with the audio via
your FM receiver. Once a match is found between the two audio signals
you have found what station he is listening to. Now you can do
whatever you please with the info. You could transmit just the FM
carier frequency for his station which is equivalent to SILENCE, or
you could be more ingenious. I take it that the offender is a regular
one? Suppose that he comes the same way evey time. You could park your
car 1/2 mile up the road in the direction he comes from. When your
gear is ready to turn on your transmitter you also turn on some
flashing lights and a siren on your car(via a CB radio link) and with
your FM transmitter aimed at him, broadcast a prerecorded message that
goes as follows "This is the Audio Police. Your listening pleasure has
been interupted because you are disturbing the whole neighbourhood.
Unless you turn your volume way down we will send you some real
powerful bass that will burn out your boom box, but not before it
blasts you through the windscreen. After this message you have 4
seconds to respond. On future occasions there will be no prior warning
before you are blown up"
The reason for the computer is the tricky signal processing to get the
audio match. Because of the variable distance to the car there will be
a variable time delay between the audio from the FM and that from the
car. It will be necessary to perform the mathematical operation of
convolution between the two signals. This will need a reasonable
processor power in the absence of a dedicated DSP and some efficient
coding for the convolution program. You might need to upgrade your PC
to a quad core.
Rgds
Roy