If you need the standard for professional use, consider these legitimate avenues:
In the high-stakes world of aerospace engineering and defense contracting, access to critical calibration standards like SAE ARP958 (Design Criteria for Precision Photometric Test Equipment) is often gated by expensive paywalls. This feature creates a centralized, free-to-access repository for non-current or public-domain reference versions of SAE ARP958 PDF documents. sae arp 958pdf free
The central premise of SAE ARP958 is . This is a measure of the loss in signal strength between a transmitting antenna and a receiving antenna placed on a test site. If you need the standard for professional use,
: It provides a standardized method for calibrating antennas at a 1-meter distance sae arp 958pdf free
ARP 958 with ANSI C63.5 (the other major calibration standard).