Just talked with Vince at WXWORX and he had no specific solutions other than trying a new antenna before I send the WXWORX box back to them. My XM antenna is mounted under the cowling (this whole system has about 425 hours of use). He said antennas have been known to go bad. So I decided to get a new one so that has been ordered and I'll give it a try. Will let you know.
Doug