MultiNav Pro+ BLE - does TX power affect the 2Mbps data rate or just range?

@Richard Davis good question — and the short answer is they're independent at the PHY level. TX power and data rate are separate settings; dropping power won't cause the radio to fall back to 1Mbps or coded PHY the way some people expect. The 2Mbps PHY is locked in by your connection configuration, not negotiated dynamically based on signal strength the way Wi-Fi does with MCS rates.

 

The catch is practical, not protocol-level: lower TX power means lower received signal strength at the receiver, which increases your packet error rate, which means more retransmissions, which tanks your effective throughput even though the PHY rate is technically still 2Mbps. At 500-800m in an open field with the MultiNav Pro+'s front-end amplifiers doing the heavy lifting, you've got a lot of link budget headroom, so you can probably back off TX power meaningfully before you start seeing that degrade. But I'd benchmark it — run a continuous stream at a few different power levels and watch your actual throughput and PER numbers rather than just assuming the link is solid.

 

For a continuous sensor data use case at that range, you're honestly in very comfortable territory with this module. The harder thing to tune is usually connection interval and MTU size if you're trying to squeeze the full 2Mbps theoretical in practice.

TX power and data rate are completely independent on the MultiNav Pro+ - the 2Mbps PHY mode is set at the link layer and doesn't fall back based on power settings, so you can drop TX power for efficiency without touching your throughput. That said, at 500-800m you'll probably want to keep power reasonably high anyway just to maintain a clean enough SNR for the 2Mbps PHY to stay stable, since at longer distances the higher data rate is naturally more sensitive to link quality than 1Mbps or the coded PHY would be. Worth running a quick RSSI sweep across that distance before you commit to a power level tbh.

Yeah Jessica nailed it - just to add, if you haven't already I'd throw in some packet error rate logging alongside the RSSI sweep, because RSSI alone can look fine at that range while your PER is quietly creeping up and killing your effective throughput on 2Mbps. Learned that one the hard way on a similar outdoor deployment lol.

Solid points from both of you - one more thing worth flagging for that distance range, make sure your antenna orientation is dialed in because at 500-800m on 2Mbps you're way more sensitive to polarization mismatch than you'd be on coded PHY, and I've seen what looked like a power or PER issue turn out to just be a slightly rotated antenna on the node end. Basically PER + RSSI + antenna check before you start tweaking TX power levels, saves a lot of headscratching later.