@Karen Garcia good question, and honestly it's one of the more important things to understand before you commit to a deployment like this.
The MultiNav Pro+ doesn't do adaptive rate stepping the way you'd see on something like a Wi-Fi stack — BLE at this layer doesn't have that kind of dynamic MCS negotiation. What you'll typically see is the link holding solid through most of your range budget, then RSSI starts compressing your margin and packet error rate climbs before you lose connection entirely. It's less of a cliff than standard commodity BLE (which just dies) but it's not a smooth throttle curve either — more like a warning zone where retries start increasing before the link goes down.
For a 15-20km ground-to-drone deployment you're well within the rated envelope, but for a static field sensor at ground level you're in the 5km ground-to-ground territory from the spec sheet, so if both ends are on the ground you'll want to think about antenna elevation and line of sight carefully — those numbers are meaningful at that range. If you can get the field unit even a couple meters off the ground on a post you'll buy yourself a lot of margin before you start seeing that packet error zone.
What's your base station setup looking like — is that also ground level, or do you have some height on that end?
