This is probably the final short-term experiment to aid with temperature calibration. The transmitter was placed in the oven again until it reported a temperature reading of '4'. It was then placed in the same location as the previous freezer experiment, at about the same ambient temperature. Again the measurements were recorded as the unit reached room temperature, and the depth reading corresponding to each temperature reading was adjusted according to the speed of sound at the temperature we believe the unit to be reporting.

These data strongly support the hypothesis that the temperature at a given reading t is intended to be interpreted as and that the observed discrepancy between that and the measured temperatures at the high end of the range is due to experimental error or miscalibration of the temperature sensor in the unit under test. The realisation that this even makes a little bit of sense in legacy units (3°F per value) contributes to the confidence in this conclusion.

At this point we might perhaps do one more experiment, leaving it in the oven at a constant temperature for a long period of time and verifying a single set point — and comparing with other transmitter units. But since we have little use for the temperature reading anyway except to perhaps account for the expansion of fuel at high temperatures, perhaps this is good enough for now.