But the core of the 406MHz PLB is a simple analog broadcast signal, right? So it just keeps broadcasting. With a data signal, if it gets missed, it's missed. No second chances. And with a data signal, a slight hiccup in signal will potentially cause the entire message to be invalid.
That is incorrect. The 406 MHz transmission is digital. That's how they can include all the identification data. Old 121.5/245 MHz beacons are analog. The 121.5 MHz homing transmission in PLBs is analog. 406MHz is Digital.
Yah, it sounds like maybe sending the message three times is their way of working around the issue. Not horrible, but users should understand how it works.
That isn't necessarily a correct assumption. They may well do a checksum. We don't know.
I assume that the 911 calls continue to broadcast over and over, but the OK check probably does not.
The 911 transmits until the battery is dead.
This would mean that it is possible for you to send an OK check/tracking and not realize it didn't get through.
Life is uncertain. Eat dessert first.
You can only do so much with the tools available. That issue is inherent in any simplex system. That's why good designs take measures to increase the chances the message gets through. A good example of that is their triple transmission. They may well have other mitigation strategies, I don't know.
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