Thanks to all for fine ideas. I disconnected ALL devices connected to my new Netgear Nighthawk router as suggested. No DropCam, no AppleTV, etc. Just cable modem and Remote Rig radio RRC are connected to the router. On the control end, I am using iPhone 5S hotspot, new Netgear Universal WiFi Adapter, and AT&T 4G/LTE carrier. Audio quality = 0 in both control and radio RRCs. Jitter buffer 10, Jitter delay 9, packet size 20.
Bottom line: I still get consistent dropouts in the receive audio. About every 3 to 10 seconds (it varies), there is a total chop off of audio for just the blink of an eye, then it's back until the next dropout. Removing all devices from my router did not affect the dropouts in receive audio. On the transmit side, no dropouts have ever been reported from other stations I have contacted. Only the receive side is having issues.
At some point, I'll try to eliminate the AT&T connection in favor of a different one. For now, I'll live with the dropouts...
73 John K7FD