[Amps] Modern AM Broadcast Transmiters

[Donald Fox]

Quoting Don:


Great Question.

  WLW was licensed for 500KW ( 1/2 Megawatts ).  Their *Peak* power  
would have been 2 Megawatts at 100% modulation.   With a steady state  
audio tone, again at 100% modulation, the positive peaks would be  
offset by the negative peaks on a slow-to-respond meter and the  
average power would have shown 500KW and the slow meter would have  
indicated no movement up or down from carrier power.

   BUT........ looking at the carrier with a fast acting oscilloscope  
would show a voltage increase from carrier levels to 2 x carrier level.

Twice the voltage into the same resistance ( antenna ) = twice the current

voltage doubled times current doubled = 4 times power. ( peak )  2 Megawatts

Current ham transmitters capable of 100 watts peak SSB can work on AM   
by insuring that your carrier ( no modulation ) doesn't exceed 25 watts.
Keep the mike audio at or below ALC threshold and you should have a  
clean AM signal.

Don W4DNR


## Outputting 2MW on peaks let along a 500 KW carrier at 700 khz lends credence to reports that folks living in and around the Mason, Ohio area heard WLW through their toasters, toilets, and other home items and appliances. It was also said that florescent lights when turned off would still produce light, or light output would vary along with the modulated signal.

Today, they have a 50 KW SS transmitter, and I believe they cover 9 states in the daytime, and closer to 37 after dark. Unlike years back, I don't think they reduce power at night.

Don  N8ECH