can anyone help me.. the tx and rx

 

If you broadcasted on the audio frequency range, it wouldn't be radio.

Additionally, you will probably anger the military of the Phillipenes (and in fact any country) as they use the ultra low frequency range for communication with submarines AFAIK. Interfering with that could get you into a world of hurt...

 

hehe. what i mean is, im trying to transmit and receive using the audio frequency range...

 

hehe. what i mean is, im trying to transmit and receive using the audio frequency range...

Yes, I know. I told you using a tx tuned to an audio range is most likely illegal. It is also impractical for sending a reasonable amount of data.

 

AND a quarter wave length antenna would be many kilometers long.

 

For clarification, could the OP say something about the possibility that this is like two way radio for voice communication?

 

How about using the easiest and cheapest method. Microphone and speaker. One of each at each end and you called call it an intercom.

Now to be serious. What is your budget? How far do you expect to transmit?

 

PS. If you have eight word questions you are likely to get eight word answers.

 

yes . the microphone and speaker maybe..i guess a few meters..

 

i dont know about intercom...
can you explain it to me clearly.. thanks

 

IR diodes can be modulated with audio and then the audio can be taken back off @ the receiver and put into headphones or speakers.

Is it a 'wireless' method you seek?

 

i dont know about intercom...
can you explain it to me clearly.. thanks

http://tinyurl.com/29lhfjb

 

yes . the microphone and speaker maybe..i guess a few meters..

Wired or wireless?

The cheapest wireless solution is a kid's wireless microphone, which broadcasts to an FM radio. Most of 'em are crap but they do work.

If you want a "public address" type thing with an amplified speaker and a connected microphone, there are plenty of off-the-shelf solutions for that too. Like karaoke machines (not that I know anything about those).