We need to transmit an optical signal over a distance of approximately 24km to an OB track. Currently, we are using Questtel SDI over fiber extenders to connect a Sony PTZ camera, including RS-485 control data. However, the fiber extenders have a maximum transmission distance of 20 km, and we are experiencing signal attenuation at the receiver beyond this limit. Could anyone advise on the use of optical amplifiers or boosters to extend the signal range, so we can avoid upgrading the existing extenders?