I purchased an XM tuner on ebay, the alpine unit... it was used. When I got it and hooked it all up it was working right away... all the channels. I called XM and gave them the serial number and they told me that tuner was NOT activated... I had it for a month or 2 and it never stopped working, then re-sold the system as I wasnt all that impressed with it. Out of the 120 channels, i only found 3 that I liked and they all played the same damn thing over and over... it sucked if you ask me.