I'm using an Oscilloscope to monitor my AM modulation envelope. I always adjust the scope so it shows a bar across the very middle of the screen that is one box up and one box down's total width.
Now I've always experienced this problem to varying degrees, but currently when I touch ANYTHING in my setup (amp enclosure, scope pickup cable, headphone wires, microphone/mic cable, dummy load, etc.) the unmodulated scope pattern changes in size (shrinks to less than 1 box up + 1 box down).
I'm keying my radio with a heavy duty metal foot pedal although I have socks and shoes on.
I can even reach over and touch my Heathkit SB-1000 that isn't even connected to anything at the moment and the carrier shrinks on the scope.
Setup is currently connected like this:
Radio -> Amplifier -> scope pickup -> watt meter -> dummy load.
The radio and the amplifier are powered off the same 13.8v power supply.
This problem has always plagued me but depending on the gear I had in line or my current shack layout it would vary in severity. I'd like to resolve it because I want to know I'm looking at an accurate representation of my positive and negative peaks on the scope. If the 1 box up, 1 box down adjustment for my carrier gets out of whack - then the accuracy of what I'm looking at when voice is applied goes out the window.
I've tried wraps around coax as a scope pickup, actual in-line scope pickups, etc. Always experience this...
Any tips would be greatly appreciated.
Now I've always experienced this problem to varying degrees, but currently when I touch ANYTHING in my setup (amp enclosure, scope pickup cable, headphone wires, microphone/mic cable, dummy load, etc.) the unmodulated scope pattern changes in size (shrinks to less than 1 box up + 1 box down).
I'm keying my radio with a heavy duty metal foot pedal although I have socks and shoes on.
I can even reach over and touch my Heathkit SB-1000 that isn't even connected to anything at the moment and the carrier shrinks on the scope.
Setup is currently connected like this:
Radio -> Amplifier -> scope pickup -> watt meter -> dummy load.
The radio and the amplifier are powered off the same 13.8v power supply.
This problem has always plagued me but depending on the gear I had in line or my current shack layout it would vary in severity. I'd like to resolve it because I want to know I'm looking at an accurate representation of my positive and negative peaks on the scope. If the 1 box up, 1 box down adjustment for my carrier gets out of whack - then the accuracy of what I'm looking at when voice is applied goes out the window.
I've tried wraps around coax as a scope pickup, actual in-line scope pickups, etc. Always experience this...
Any tips would be greatly appreciated.
