2 Ptp links and I lose half the bandwidth

RouterOS Wireless Networking
1

I have a network setup with all routed ptp link using all RB800

I have 3 sites, in a line with 3 ft dish antennas facing opposite directions with about 10 foot of height between the antennas.
The channel spacing is over 400Mhz apart

If I do a bandwidth test from A - B I get 100 megs.
If I do a bandwidth test from B - C I get 100 megs.
If I do a bandwidth test from A - C I get 30 megs.

How come I lost so much going from 1 wlan to the other?

thanks

2

What kind of test did you carry out? What was the source and target? TCP? UDP? Are the links full or duplex?

3

I used the MK bandwidth test in TCP mode and all the links are 802.11N / NV2/ Dual pole

4

I have seen similar behaviour long time ago when using routerboards with more than 1 wireless card, therefore started to build x86 with 2 or 3 cards max. Usually the root cause of this was shared IRQ but that was before NV2 was introduced.
Could you check if your cards uses different IRQ? Did you try to swap the miniPCI ports? I would personally go the way with 911s = single wireless card in one routerboard.
Also it could be NV2 causing this issue as I have seen someone on this forum describing the same issue when using NV2 on 2 wireless links on shared board. Could you try to switch to 802.11 if it help?

Can you also provide more info, like ROS version, wireless or wireless-fp?