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Ralph Furman of Newport Beach, California, asks:

"I use wireless sensors aboard my Hunter 45DS to monitor temperatures for my refrigerator, freezer, engine compartment, engine-cooling system and air conditioning. My system works fine except for two hours a day when the engine compartment and refrigerator readings go blank. But during the other 22 hours everything is fine. What is making these sensors blank out and can I fix the problem?"

Gordon West replies:

The blank-out period you describe is occurring because of what’s called data collision. All the sensors transmit a UHF data burst several times a minute, and when two sensors transmit at exactly the same time the receivers pick up an error signal and respond by going blank. Each transmitter has its own internal clock and because these vary a second or two over a 24-hour period, it is not uncommon for two signals to be transmitted at the same time each day.

To fix the problem, reboot one of the sensors by either removing the battery for a few seconds or pressing the reset button; this will change the internal clock’s transmit time. Watch the read-outs for a day and if you don’t get blank-outs you should be fine for at least 30 days. Since you have so many sensors operating on the same channel, there’s a good chance you will see some more blank-outs each month. But once you know the cause, it should be easy to correct the problem.

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