I constructed this rf amplifier:
http://ba1404.blogspot.com/2010/06/1-watt-universal-rf-amplifier.html
I am using this amplifier for a video transmitter with audio. The circuit works really good, and the video is very good, but I have an irritating background hum in the audio. Any RF pros here? I'd like to dramatically quiet the hum, or eliminate it. I tried different rf coils(also compressed/expanded coils), added a trimmer in place of C1, and I also made sure of the calculation for my frequency. my RFC is an epoxy coated inductor of the desired value, and the 2 other coils were made from 20ga wire on a 7/16" form...to the desired turns/values. I also made a custom steel enclosure for the entire circuit, and use a coax connector at the input/output. Can I add a high value resistor somewhere? Or an additional pico capacitor? All help appreciated. Thanks
http://ba1404.blogspot.com/2010/06/1-watt-universal-rf-amplifier.html
I am using this amplifier for a video transmitter with audio. The circuit works really good, and the video is very good, but I have an irritating background hum in the audio. Any RF pros here? I'd like to dramatically quiet the hum, or eliminate it. I tried different rf coils(also compressed/expanded coils), added a trimmer in place of C1, and I also made sure of the calculation for my frequency. my RFC is an epoxy coated inductor of the desired value, and the 2 other coils were made from 20ga wire on a 7/16" form...to the desired turns/values. I also made a custom steel enclosure for the entire circuit, and use a coax connector at the input/output. Can I add a high value resistor somewhere? Or an additional pico capacitor? All help appreciated. Thanks