May 22, 2020.


The first few measurements were some variations of the terminating resistors.
Channel 1 was connected to the end of the pos wire, channel 2 was capacatively
coupled to the begin of positive wire at the relay and channel 3 was
capacatively coupled to the end of the positive wire at the termination
resistor (potentiometer). 

000-001: show the beginnig situation, whereby both termination resistors were
set to about 375-380 Ohm.

002-005: shows what happens when the pos resistor is set to 0 ohm and then
gradually increased.

Then it was found we obtain a significant reflection when the pos resistor is
set to max (500 Ohm) and the neg resistor is set to 0 Ohm. These reflections
are only picked up by the active probe at the end of the pos wire. Changing
the ground from the active probe to the passive probe did not seem to make a
difference (compare 020 with 021).

006-020: measurements of the timing of the various peaks that are observed.

021 : single measurement with ground via passive probe (channel 3).

022-025: channel 1 connected to begin of positive wire, at the same point as
channel 2.

026-053: same situation. Accidentally moved the position of the trigger bar,
so redone some and continued. 

054-058 : moved channel 1 to begin of negative wire, at the relay. A signal of
about 1.6 MHz was observed to interfere. The signal was gone after about 30
minutes (058). This frequency is within the AM broadcasting band, so the
signal was possibly caused by a local AM radio pirate. 

059 : Signal delay between active and passive probe as about 4 ns.

060-111: measurement of the timing of the various reflection peaks observed.

113-116: zoom out to lower sampling rate for an overview.