R11e RX problem, missing db

Hardware MikroTik hardware general
1

hello,

we are using Mikrotik hardware since a long time, nearly 8 years for now.
RX, TX, dbm, etc. is nothing new, but now we are having troubles with some R11e hardware.

Since one year we are using a basebox5 with R11e-2HPnD miniPCI card (AP1). No problem with this setup at all, all signals are nearly symetric.
So we intended to renew our second AP (RB433AH with XR2), and set up a RB912UAG-5HPnD with the same R11e-2HPnD, bought one month ago (AP2).

The problem now is, that TX signal at client side is ok, around -60dbm, but RX signals of all clients are around -80dbm.
So about 20db are missing, or in other words, the RX signal is too weak.
Today we changed the R11e card against another R11e, bought 6 months ago.
But hell, the same RX problem, 20db still missing on this second new card.

In both cases we are using only a vertical antenna (chain0), but neither chain0 nor chain1 did bring any change to AP2 RX signals. The problem occured directly after renewing AP2, so the antenne is OK, the pigtail and cable too (tested).
It’s an asymetric signal, only RX is effected.

Could it realy be, that both new R11e cards (out of different charges) are having the same RX problem, a defect?
Or is there any parameter that effects the RX signal? Didn’t think so.
bad-rx.JPG
best reg.
Mike

2

BTW:
Both systems are working with the same RouterOS version v6.33

Possibly anyone knows how rx/tx switching is done, wether direct on the miniPCI card, or via command from the routerboard itself? Maybe here is the fault?
I intend to change the routerboard to do a further test on it.

best reg.
Mike

3

Changing the routerboard also did not help.
Very strange behavior.

Could a signal be measured worse if there is a noise source on the whole band?
IMHO a noise source should not affect the effective signal strength of a client.