Why is that?

[gunny]

Drive under some over passes and my Sirius radio drops out for a couple of seconds. Park under the overpasses in down town Atlanta and never loose reception, shows real good signal strength.

They got some sort of repeater system in place? Good cell reception there too.

[Dick]

Drive under some over passes and my Sirius radio drops out for a couple of seconds. Park under the overpasses in down town Atlanta and never loose reception, shows real good signal strength.

They got some sort of repeater system in place? Good cell reception there too.
Sorta the same here in Cheryl's cage. Back up the drive and into the garage and the antenna just enters the door opening - zap goes Sirius. Continue backing into the garage and park and Sirius comes back up and plays just as strong as normal. Must be some sort of software that reckons with decreased signal strength.

[DaveDragon]

I major markets, XM/Serius uses land based FM to augment the Sat signal.

[WildBil]

Yes, as Dave says, XM went with 1 - 3 large land based repeaters in major markets. Sirius went with many small transmitters.

The father north (or on the other side of the planet, the farther south) you go, you will lose the signal parked on the north side of buildings in small towns which do not have repeaters.

FWIW, most XM receivers have a 3 -5 second delay due to the buffer they have to avoid signal loss in underpasses or passing large buildings. I don't know about Sirius.

My XM works fine in my garage, but its just plywood and shingles above. Metal would be a killer for the signal.

bil