Also, consider if "crack" here is a verb or noun. If it's a noun, maybe the portable crack is the device itself.
: Cracks often appear near the base or the joint where the radiating element meets the plastic sleeve. portable crack atas link
The terms "portable," "crack," and "atas link" in this context typically refer to mechanical failures (cracks) in the antenna's weatherproof housing or the specialized cables and connectors (links) used to integrate the antenna with a radio like the FT-817, FT-857, or FT-891. Technical Overview of the ATAS System Yaesu ATAS-120A Also, consider if "crack" here is a verb or noun