Multiplexed data services on AM

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Palapaguy
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Joined: Sat Nov 10, 2012 1:23 pm

Multiplexed data services on AM

Post by Palapaguy » Sat Nov 10, 2012 1:43 pm

Multiplexed services have been de-regulated on AM broadcast transmissions per CFR § 73.127. Can any kind soul tell me the best way this service can be implemented? My company needs to broadcast a 50 bit/s data service in a metropolitan area in CA. I'm a relative newbie in this field and I don't know what the options are.

Looks like AMSS is technically suitable for our service, but is it being used at all in the US? Or how about sharing some OFDM bandwidth on an existing IBOC channel at about 170 Hz from the carrier?

In general, is ANY broadcaster selling low-rate data service bandwidth on its AM carrier? I have heard that this is being done in certain applications such as controlling traffic lights and controlling AC utilities, but I haven't been able to find out anything useful by Googling.

Tuning around the AM band with a SDR, I see numerous carriers with sidebands a couple hundred Hz away from the main carrier. They look pretty different from one another and I can't tell what they are. I have called the stations to ask, but not one has returned my call.

Any insight will be greatly appreciated.

George
K6GW

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Deep Thought
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Location: La Grange, IL
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Re: Multiplexed data services on AM

Post by Deep Thought » Sat Nov 10, 2012 3:24 pm

A couple hundred Hz from the main carrier would be very audible so I doubt that you are seeing any sort of data transmission there unless it is in quadrature with the carrier.

By the way, that rule section is 30 years old.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

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