Re: DCC Meters
On larger layout without a load, you will see the track voltage go up the further you get away from the DCC system or booster powering the track.
The is voltage ringing (spike) on the DCC waveform created by the layout wiring that confuses the meter into reading a higher voltage than what is actually there.
The use a of a ten scope is good in that one can visually ignore the leading edge voltage ringing (Spike) and focus on the flat portion of the DCC waveform for the reading.
The advantage of having a resistive or locomotive head lamp load is it consumes the voltage ringing/spike by absorbing it. Your presented with a much cleaner reading.
To check for voltage drops in the wiring, you will need a large lamp load such as offered by an 12V automotive lamp.
DCC Website & NMRA DCC Clinics: www.markgurries.com