Tower_Q A_021116.pdf

AG-1484-S-16-0005 WMNF HQ Antenna Modification/Radio Frequency Cabling and Tower Questions& Answers 02/11/2016

1. Is a ground ring needed or simple ground rods in each corner for the shelter? R56 says that there should be ground ring around the shelter and one around the tower using a minimum 2/0 cable, and those should be tied together at 2 points (for redundancy, also with 2/0 cable) to present a single grounding system. All metallic components inside the shelter should be bonded to a master ground bus, which is then bonded to earth ground, providing a single point to ground. All connections should be made using either an exothermic weld or by irreversible high compression crimps. No mechanical connections. The number of ground rods would be determined by performing a soil resistivity test (4 point Wenner test) using a Megger or similar set.

2. I do not know the answer to the coax question either but the shelter has a ground bus bar that the grounds mentioned above are attached, I assume antenna coax ground to that correct?

Yes…sort of. The shelter should have an internal Master Ground Bus for all interior connections and an external bus bar for all exterior connections, both of which are bonded to the ground ring. The coax ground kits connect to the external bus. See attached images 0514 and 0532 for examples.

3. Do you want cable ladder on tower or brackets? Cable ladder with ¾” holes to use snap in hangers. See attached image 503. It’s integrated into that particular tower design, but same concept.

4. The air conditioner unit is made to function on either 208 or 240VAC. Do you folks have issues with voltages from 3 phase source? The shelter outside power disconnect is not needed unless electric code requires. As long as we have 120V single phase present at the receptacles, you can run 3 phase 208.

http://www.esgroundingsolutions.com/what-is-soil-resistivity-testing/ http://us.megger.com/4-terminal-earth-resistance-and-soil-resistivity-testers-megger-det4t2-series/ azero Typewritten Text