[Phlogiston]

Hi..i am a new user here. As per my knowledge the counter has a MOSFET front end and a pair of back to back protection diodes from input to ground, so if the signal is more than 0.7 v peak the diodes will conduct and load the measured circuit. Better to add a series resistor to reduce signal if it is at high level as in a tube osc circuit.

I have found that I can overdrive it and attenuate the signal to the point that it can not be read. Also putting more than ~ 20% modulation on the signal will cause the reading to jump around about 5k.