I have noticed that XM tends to make the traffic/weather people sound like robots a bit...
Same thing on Sirius- sounds normal.
Also- if XM is like Sirius---
sirius does this in major cities...
they have 'repeaters'- transmitting the signal--- that way if you lose the signal from overhead- you can capture the signal from the repeaters.
This to overcome problems with bldg interference and you dont hear a break in the signal.
In areas where they dont offer the in city signals- youll notice the break in the signal.
If I recall correctly- my portable sirius unit- has a feature where I select it- and it shows the signal strength of the satellite and the city signal--
it shows bars for both.
I know the XM satellites travel differently in the sky than the Sirius satellites do...
So I dont know how far south- the signal would reach---
But when Ive drive to Guadalajara Mexico- I can listen to my Sirius unit- way down there---
though in the city--- on narrow trees--- lines by small 1 story homes--- these block the satellite signal- meaning that the satellite is actually about lets says 25 degrees above the horizon--- instead of the 90 degrees (overhead) like in the US...
below is a map- showing Los Angeles where I live-- and the path (in red) of the route I take to go to Guadalajara.
As you can see its halfway down into Mexico- Its interesting how I can tune into the traffic conditions of LA- while way out there.