Total posts : 45366
The 100 mW. limit applies to unmodulated power input to the final stage of a transmitter. There is no reference in the rules to modulation percentage. The 237 mW. reading I cited was unmodulated. The transmitter was adjusted for best audio at 100% modulation and then I measured the power input with no modulation which is the standard practice for AM.
I have a problem with the 125% modulation that many talk about. It appears to me that the only way this will happen without clipping the carrier off at zero is to distort the audio on the positive peaks or to supress the carrier which requires sophisticated ciruitry. There is a technique called exalted carrier (it should be called exalted sideband) which hams used to use. On AM, half the total power of the tx. is in the sidebands at 100% modulation. Be careful with this….a .1 watt carrier power tx. at no modulation has .1 watt in the carrier. At 100% modulation this tx. has .1 watt in the carrier and .05 watts in the two sidebands resulting in a total power with modulation of .15 watts. With exalted carrier, the sideband power is boosted above the 50% level for AM so the power in the sidebands exceeds the usual 50% at 100% AM modulation. This appears to me to be equivalent to the 125% modulaton that some speak of. I cannot see how this is done with simple circuits without distortion of the audio. Perhaps this technique is approaching double sideband supressed carrier mode which would not distort the audio. Maybe you or others can help me with this.
No, I have not heard of Chris Hood Electronics. Thanks for the tip. I will pursue this.