Everyone,
I have been trying to use a capacitive-element microphone with my Flex5000. I have attached the diagram of my microphone connection. The 470-ohm resistor and the 6.8 microF capacitor are mounted at the front panel plug. I am using the 5V power, which is available on pin 2 of the plug, as the bias for this microphone. The microphone is working and gives a reasonable modulation level. However, a low-level, approximately 2 KHz, oscillation is occurring. This oscillation continues even if I unplug the microphone and its cable! So, this oscillation originates from this simple two component circuit not from the microphone or its cable. I can see this oscillation signal as a small spike on the Flex5000 spectrum display. This 2 KHZ continuous tone can be heard in my transmitted signal. I have tried different values of the capacitor and the bias resistor but the oscillation persists. Has anyone out there had success using a capacitive-element microphone with the front panel connection of the Flex5000? Any help would be appreciated. Paul, K9IRO _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
