UMTS antenna cable

Hello

I have UMTS YAGI XP 15 dBi antenna ( BESTPARTNER.biz - wireless technologies - wifi 2,4 GHz 3,5 GHz 5 GHz antennas accessories tools cables - wireless networks ) which is superb, but recently someone cut my cable.. Which cable should I buy for replacement? Can I join the old one with the new one?

This cable is a coaxial type, probably designated RG174U which is the most common type in this size. Your antenna operates at about 2GHz which means that the quality of coaxial connections is critical. You cannot simply repair the cut by soldering the wires back together as you may lose many dB of performance with such a repair. There are two ways to fix this. One way is to replace the entire cable and the other way is to install SMA coaxial cable connectors on the two cut ends and then reconnect the cable. However, installing the connectors is impossible without the correct tool and some experience, so the best thing is to replace the entire cable.

This kind of cable is not difficult to buy, but as I don't know where you live, perhaps it would be best to contact the original seller and ask him to sell you a replacement cable.
Part number 20855 looks correct.