Hello It is the first time that I buy a Basebox 5 and accidentally I power on it without connecting any antenna connected because I was really excited to use this routerboard.My question is what problem can present the basebox after that,because it is new and I used it only for 15 minutes.Please help me.Thanks.

Most likely, there will be no problem, because the built-in pigtails act as small antennas, and you didn't use it for very long.

The only problems could be if you power it with maximum transmit power (connected somewhere and sending over bigger distance), and for a long time. Then the transmitter could get damaged.

Newer products like the Basebox are better to withstand such things, only older devices could have the transmitter damaged in this way.

I feel better after reading your comment.I hope to share my knowledge and learning more about mikrotik in this forum.Thanks.