Hi!
Please, how can I correctly set TX-RATE on an P2P-Link?
I have two MT RB112 and a quite good link 
2 wlan1 sporthalle2 00:0B:6B:34:09:41 yes -84dBm… 5.5Mbps 4m5s
Sometimes TX-Rate drops to 1Mbps an comes back to 5.5Mbps.
Is that OK? Can I fix it to 5.5Mbps ?
I tried to do that, resulting in a dead link?
Is there a howto for dummies?
Set your Basic rate to minimum 1 or 6 Mbps and your supported rate to 5.5 Mbps. Treat your basic rate as minimum and supported rate as maximum. When you set your basic rate to ONLY 5.5 Mbps, then if your links drops to less than 5.5Mbps, then the whole link is droped by your MT unit. To secure a minimum of 5.5Mbps, you should enhance your link, either better allignment/hight or higher gain or better antennas might be a start.
Signal is kinda low. Same problem I have with my link.
I do wonder what most of these guys use for a cut off point, -75 seems to be standard on 900MHz, what about 2.4GHz and 5+GHz?
I’d think at least the same. You find more noise on 900MHz, but more loss over distance, rain, fog, etc, with the higher frequencies.
I know I have a few hotels in mesh with -85 or worse running their AP’s in WDS, but I’ve had some complaints there as well recently. From what I’ve dealt with these guys tho, they tend to complain about everything.