While the abused relay performed surprisingly well (see here) it did start to degrade. After 6,449,686 cycles the contacts did not open for some 63 cycles. The evidence for this was the declining voltage across the contacts as the constant current regulator warmed up and current limiting set in.
After this point there were numerous "runs" where the voltage across the contacts was much higher than average.
If relay performance is considered as good then degrading to failure, at what point has it failed? Apart from the periods of degraded performance the relay is still switching reliably at 8.4 million cycles.
In light of the degradation seen at 6.4 million cycles I went back through the data. If the symptom of contacts not opening correctly is a decline in the voltage across the contacts over time, then the relay's first, albeit brief, period of degradation started at 44,296 cycles.
It would appear that the relay is still fit for the intended purpose of TX/RX changeover. Now it's time to sort our the isolation and loss characteristics.
73's
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