When running a transceiver on AM you want to avoid hitting the ALC altogether. This includes the ALC function in the radio as well as the linear. As soon as you trigger the ALC, the carrier level abruptly drops down, producing a distorted, anaemic sounding "negative controlled carrier" effect. If there is an easy to do so, disable the ALC altogether when running AM. Otherwise, keep the positive peaks just below the ALC threshold. ALC is designed for SSB and was never intended to be run with AM.
If the ALC cannot be disabled, it can serve a useful purpose as a positive peak overmodulation indicator. Run the output just under the point where you begin to see some indication of ALC action on voice peaks. The best way to make sure the signal is fully modulated but that nothing is being pushed into the flat-topping/distortion region is to monitor the envelope pattern of the signal with an oscilloscope. At one time, all major manufacturers offered a monitor scope as a matching accessory to go with each of their transceiver lines. A modulation monitor scope is NOT the same thing as a modern transceiver's panoramic display. To me, operating a phone transmitter (AM or SSB) without a monitor scope is like driving a car at night with the headlights turned off. Don k4kyv _______________________________________________________________ This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/ ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
