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boosting the range on AM transmitters

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SlicRic

New Member
Hi,
I am going to build a small AM transmitter, but I would like a significant range, about 100 meters, what I need is a circuit for an RF booster, so I can put the two together and get a better range, does anyone have a circuit like this?

Thanks SlicRic
 

audioguru

Well-Known Member
Most Helpful Member
It is illegal to cause interference on the broadcast bands. The harmonics of your interference will also probably be on other radio bands.
You need a licence and accurate certified circuits to make a radio station.

The AM broadcast band is at such a low frequency that very long antennas are needed or directional loop antennas.
 

tcmtech

Banned
Most Helpful Member
If your not someone like Howard Stern I doubt they will come looking for you and your 100 meter transmitter. ;)

My military surplus 5 MHz waveform and frequency generator has a 50 ohm output rating and can easily produce an amplitude modulated wave form in the AM radio broadcast band. With the right coil and capacitor it will transmit an AM signal just fine.
All I do is set it to what AM radio frequency I want and feed an audio signal into the external signal port and its now a full AM radio transmitter!

I dont need a FCC license for owning a waveform and frequency generator! :)

The FCC has far bigger and more profitable fish to chase! :p
I suspect the AM radio band may be the next public frequency band to get sold out and converted to something more useful in the next 10 to 20 years.
The old timers are about the only ones that still listen to the stations there now any way. In 10 -20 years they will be dead and thusly the remaining market will be gone.
Just a theory. ;)
 

audioguru

Well-Known Member
Most Helpful Member
AM sufferes from interference at the same frequency as the wanted signal. FM has the advantage of a "capture ratio" where interference is not heard unless it exceeds a certain fairly high level.

100 metrers could have many AM radios in it that might receive interference.
 

tcmtech

Banned
Most Helpful Member
I keep for getting I have the advantage of rural living. My nearest neighbor is over two blocks way.
Playing with AM transmitters could feasibly cause some type of local interference with local radios but then again AM get interference from every thing else too! The few AM listeners would probably not even notice!
 

stevez

Active Member
What are you trying to accomplish? I ask that question because your response might help with a proper response.

You ask about AM transmitter. Did you mean for the AM broadcast band?

Where do you live? That might be important as someone here might understand the rules and have a solution for you that is compliant with the rules.

What is it that you intend to transmit - voice, data, other?

Can you improve the receive end of the system? If you are looking at the AM broadcast band a tuned loop on the receive end might reduce or eliminate the need for more power on the broadcast end.

Regarding the rules, it is not uncommon for illegal transmissions to be discovered by neighbors - or other more sophisticated users of the RF spectrum. It is often the case that a commercial, industrial or military user will be bothered by an unwelcome signal and will seek to track it down and make it go away. As a relatively active radio amateur in my area, I am often asked to join a local effort to find the source of an emission - usually because it's creating interference. Usually the source is unintentional - often a malfunction.
 
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