Hello,
Placing the RUT240 on the mast should not be an issue. Make sure you are using passive PoE to power it on the LAN port, and the pairs described here are used for power.
As for waterproof enclose, we do not sell such products, however, our partner Poynting sells antennas, which can be used to house the RUT240. I would recommend reaching out to them to find out which antennas would be suitable for your use case. Let me know if any more information is needed!
Best regards,
DaumantasG