Hello. Can anyone help me determine the maximum realistic data transmission rate using the AM radio frequency band? Is it possible to send web pages (HTML or similar format) or such text using this medium? I understand there are capacity formulas. Perhaps assuming a reasonable signal to noise ratio someone can give me an idea?

Thanks!

 

Hello. Can anyone help me determine the maximum realistic data transmission rate using the AM radio frequency band? Is it possible to send web pages (HTML or similar format) or such text using this medium? I understand there are capacity formulas. Perhaps assuming a reasonable signal to noise ratio someone can give me an idea?

Thanks!

A.M. broadcast stations are limited to a bandwidth of 15KHZ (A.M. modulating frequency of 7.5 KHZ. 7.5 KHZ would be the approximate limit of your baud rate.

Experiements with IBOC (in band on channel) A.M. broadcasting achieved higher baud rates using QAM (quadrature amplitide modulation), but would require special licensing for non broadcast applications.

eric

 

Eric,
Thank you for the reply! That is a huge help. I think it sounds like 7.5kbit/second is the best you could do in perfect conditions without exotic methods. What do you think is possible with QAM? 10's of Kb/s?
Thanks again,
Nick

 

Eric,
Thank you for the reply! That is a huge help. I think it sounds like 7.5kbit/second is the best you could do in perfect conditions without exotic methods. What do you think is possible with QAM? 10's of Kb/s?
Thanks again,
Nick

According to Shannon, in perfect conditions there is no limit, however it would require exotic methods. If you mean 'practical methods' then you could take a 56kbps modem that works in a 3kHz channel and modulate with that. It also has the benefit that it will automatically negotiate a lower rate if hte channel is poor.

I don't know whether you have to work within any license conditions, I don't know of any regulatory regimes that would allow you to do that without special permission.

 

In the USA it is NMT 10mw signal and an antenna not longer than 10 feet.