The circuit attached is an SWR bridge for part of a powerful LF (136kHz) TX. The meter used in the schematic is 0.25mA FSD and 300 ohms internal resistance, which I am ignoring for now. I want to use a 100uA meter instead, as that's what i have a few of. I can't quite get my head around whether the two 100k resistors are both in series in both positions of SW3 or not, and thus whether I need to change the two 100k resistors for 250k each. I think because one side of the meter is grounded the two 100k resistors are not effectively both in series, can someone clarify please? The meter is only for a relative reading of forward and reflected power, not needing to give absolute readings. The trimmer capacitor should null out reflected when transmitting into a dummy load. Thanks!