What is this?

Bryan Mayland

TVWBB Honor Circle
It is telling you there's excessive noise detected on that probe. Red would indicate a virtually unusable signal. If you're logged in and on a recent snapshot, you can click on it and it will display a graph dump of the last probe read cycle. Probe noise can come from moisture getting into the probe, crosstalk between other probes coming through the wire shields, a damaged conductor, ground noise travelling in from the grill's metal bits, or a noisy power source.