FM Transmitter aka Spy Bug

[electronoobz]

i want to make one for me and my friends. A small one with a static frequency, if possible higher than what a radio could reach and just make a special receiver for it.

is this possible? Thanks. I wish it is possible and small in size.

 

[donkey]

i want to make one for me and my friends. A small one with a static frequency, if possible higher than what a radio could reach and just make a special receiver for it.

is this possible? Thanks. I wish it is possible and small in size.

what do you mean by higher?
why would you want a special reciever for it? this defeats the purpose of being an fm bug, it then turns into a super secret bug with special reciever possibly using the fm bandwidth.

anyway if you are doing what I think you are then try a walkie talkie. if this is for spying then go buy one from a retail shop and while you're there ask them the legalities pertaining to invasion of privacy and the fines/jail time you could be facing if the device is improperly used.

 

[(*steve*)]

Look here. Typically they transmit (illegally perhaps) to normal broadcast band radios.

 

[CocaCola]

Sure it's possible, is it practical (or cost effective) is the question...

For $15 you can purchase one that is cellular...

http://www.ebay.com/itm/Latest-Mini...t=US_Surveillance_Gadgets&hash=item27c79a2a9a

For $10 or so you can get FM ones...

http://www.ebay.com/itm/Smallest-FM...t=US_Surveillance_Gadgets&hash=item43a9344742

 

[electronoobz]

yah! That's it. A walkie talkie similar.

i dont want to get caught by others.

let's say the max. freq the radio can seek is 107 mhz. I would like to make a receiver with a freq of 108 mhz. Get it now guys?

 

[CocaCola]

i dont want to get caught by others.

Then don't do it...

let's say the max. freq the radio can seek is 107 mhz.

You can say it all day long, doesn't make it so...

I would like to make a receiver with a freq of 108 mhz.

Get a radio scanner or twist the dial just that much more on an older analog radio...

Get it now guys?

We never didn't get it...

 

[electronoobz]

didnt get your reply.

what im trying to do is make a hi freq spy bug and make a special receiver for it. Lets say that my target freq is 110 mhz because it's a freq our radio cannot reach.

 

[CocaCola]

what im trying to do is make a hi freq spy bug and make a special receiver for it.

Yes, we know what you want, no one is confused... You are likely to not find much help here as it's illegal in most areas to do what you want to do... That is unless you have a broadcast license for said frequency...

 

[electronoobz]

ok. I found a scheme but it's highest freq is 107 mhz. How will i increase it?

 

[(*steve*)]

smaller inductor and/or capacitor in the tuned circuit(s)

 

[davenn]

ok. I found a scheme but it's highest freq is 107 mhz. How will i increase it?

retune the oscillator to a higher frequency


You still dont seem to understand that radio receivers DONT stop at 108MHz.
There are all sorts of receivers that cover huge ranges of frequencies.... as one of the other guys mentioned scanners

My scanner goes continuous coverage from 100kHz to 2400MHz. it will pick up your signal regardless of the freq you used in that range ( if I lived in your region)


Dave

 

[electronoobz]

smaller inductor? Like decreasing the number of turns of the original?

how about the other one with the caps im a bit confused.

 

[electronoobz]

dont worry sir Dave. 108-110 mhz is fine..

 

[electronoobz]

bump..

 

[(*steve*)]

Decrease the number of turns (you're probably looking at very few turns anyway, so reducing it by 1 turn may be plenty. Alternatively you may be able to just stretch it out a bit.

 

[electronoobz]

let's say i did it already and im ready to build its special receiver. What freq should i set it? Thanks steve. Just a little bit more and im ready to build it

 

[CDRIVE]

New definition of "privacy": An archaic concept once thought sacred by early man.


Chris

 

[davenn]

let's say i did it already and im ready to build its special receiver. What freq should i set it? Thanks steve. Just a little bit more and im ready to build it

there's no such thing as a "special receiver"

you just need a receiver that covers the frequency of your transmitter

Dave

 

[electronoobz]

that's what i mean sir.

 

[(*steve*)]

Get a receiver and transmitter that work together then make similar modifications to both.

And call him Sir.

If you're using a standard FM radio, you *may* be able to "tune" it (de-tune actually) to cover a slightly different range of frequencies.

Perhaps more reliably, you just go out and buy a receiver that covers the band you're interested in.