Re: Help on a strange problem

[Jim <alarminex@xxxxxxx>]

On Aug 26, 11:11=EF=BF=BDam, goodday <chris....@xxxxxxxxx> wrote:
> On Aug 26, 8:42=EF=BF=BDpm, Frank Olson
>
>
>
>
>
> <use_the_email_li...@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> > goodday wrote:
> > > I recently manage to get hold of a RF scanner. I use it to scan the
> > > living room of an apartment. The scanner beeps in mid air when a huma=
n
> > > body object is near to the scanner. Can some one tells me what can
> > > possible to the cause?
>
> > > Is it possible for the reflected frequencies from a motion detector t=
o
> > > trigger the beeping sound?
>
> > "Human body object"... =EF=BF=BDHBO... =EF=BF=BD"New show every day." =
=EF=BF=BD:-)
>
> > Seriously... =EF=BF=BDAn RF scanner is liable to pick up any RF (depend=
ing on
> > the quality of the unit). =EF=BF=BDWhat's the make and model #? =EF=BF=
=BDIs the security
> > system in the apartment a wireless job? =EF=BF=BDBefore we can answer y=
our
> > question, we need some more info.
>
> I use a normal RF scanner call pro hunter. It has a wide RF range. To
> my knowledge there is no security system installed in the apartment. I
> tried using the scanner in other parts of the apartment it doesn't
> beep. Most of the beeping is in the living room. The strange thing is
> it beeps in mid air at a distant away from the floor and ceiling. If
> you move away to one side, it stops beeping. Please help me to
> understand.-

What  you really have is a broadband RF receiver.

What you don't know, or haven't considered is that there are radio
frequencies around us, every where we go. Look up "Beat Frequencies"
It's basicly the same process that is used in hetrodying radio
receivers where they take a received broadcasted radio frequency, join
it with a known frequency which is produced by the radio circutry and
when the two are joined, it results in a third frequency. Basiclly,
that third frequency (beat frequency) which is produced, is the sound
you hear coming out of your radio.

Now, if  you apply that same process to all of the radio frequencies
that are around us every day, there are going to be random "hot spots"
where multiple frequencies "beat" together which produce first,
second, third etc, etc, etc,  harmonics which you can pick up very
easily with a broad band receiver. If your RF detector had a
hetrodying circuitry and an amplifier in it, you'd actually be able to
hear what was being received, if some of the components of the signal
where from commercial radio stations. Sometimes you can hear military
transmissions, ham radio, business information data transmissions
( such as OTB).  Sometimes you can hear radio stations from the other
side of the world. AM radio transmissions bounce off of the ionosphere
and can travel great distances. Actually your receiver is almost the
same as one of those world wide trans-oceanic radios that you can buy,
however they are broken down into tunable frequency "bands". Your
receiver likely just receives all frequencies in the radio spectrum
simultaniously.