Hi,
I was wondering if anybody might know, why my AP910c will stop transmitting on the 5GHz network after a while ? and I have reboot the box to make it work again. As it seems to work fine and then stop working and then I repeat the reboot and all working again - which seems a little weird - can other networks around cause problems?

Thanks
Mark.

Try non-DFS channels of 36 to 48 to see if that helps. The channels above that need to scan periodically to check whether the frequency is in use by Radar & other higher priority radio systems.

Beyond that, check the access point's syslog output, that should give an indication of why the 5GHz wireless LAN is not broadcasting.

Try setting it to used Channel 36 instead of automatic.
I found out long ago that the automatic may move it to the higher channels that some devices just don't support, hence they would just stop working.
Since setting to 36 I've not encountered it again.
Also make certain you have the firmware up-to-date just in case.

If you find that the VigorAP is moving up to unsupported frequencies when its forced to move by a DFS check, you can set which channels can be used in the [Wireless LAN 5GHz] > [Advanced Setting] page.