User's Manual

9. Troubleshooting
• Polarization incorrect
Install the unit with the correct horizontal or vertical polarization: The arrow mark (placed just next
to the Status LED) indicates the unit RX polarization. When the arrow is perpendicular to the earth,
the unit receives a signal in vertical polarization. When the arrow is parallel to the earth, the unit
receives a signal in horizontal polarization. The connectors must point downward at an angle.
• The link cannot be established
Start with the most “resilient” configuration. This configuration depends on the type of unit. We re-
commend using the narrowest available bandwidth (e.g. 3.5 MHz), the lowest modulation level
(QPSK) and maximum available output power. TX and RX channels must be the same as the RX
and TX channels in the remote unit. When the connection has been established and the antennas
have been directed, proceed with operation parameters.
Units operating in licensed bands (RAy2-10, RAy2-11) are mounted with the same RX polarization
(the polarization indication arrows show the same polarization on both units).
Units working in the bands equipped with RAy2-17 and RAy2-24 units must be mounted with opposite
polarization; one with RX horizontal polarization (horizontal arrow) and the second with RX vertical
polarization (vertical arrow).
• Access to the Local unit is blocked
Access to the Local unit may be accidentally blocked, for instance by disabling HTTPS access. If
you can access the Remote unit over HTTPS, type its address in your web browser's address field.
The link will transfer the packet over the Local unit with blocked service access all the way to the
Remote unit, which will give you access to the control menus of both units. Warning, the Remote
unit will report as Local.
• Distinguishing Local-Remote
A unit accessed via service access always reports as Local. If you connect through another (peer)
unit and radio channel, a certain amount of caution is necessary. For example, do not reduce the
transmission power so that the link interrupts accidentally. Errors of this type should be fixed by the
rollback function within approx. 1 minute.
Resolution can be done by comparing the length of ping on Local and Remote. Pinging the unit
behind the radio channel is slower. The difference is more pronounced in the case of a long packet
and the low speed of the radio channel.
• Access security
For better protection against unauthorised access to configuration you should only allow as few
kinds of access as possible. The most secure type is SSH with key – leave only SSH active with
"only key" choice.
• RSS
To configure the link and monitor its state, several menus display the RSS signal strength. Please
keep in mind, that Ray2 is not a measuring instrument, hence the precision of the RSS reading is
RAy2 Microwave Link – © RACOM s.r.o.170
Troubleshooting