Sirius's Satellite Signal
This is a map of Sirius service coverage area based on Sirius's data, actual reports of subscribers, and our radio sales. The deeper the color indicates a more direct, and often stronger, satellite signal. This is what you should point your antenna towards.
Please note, this is also not a map of where the signal from Sirius's satellites can be easily received, but not where the signal can be detected with stronger equipment (the extended satellite footprint). It goes farther beyond this map, covering most of the Western hemisphere, from Hawaii to the coast of Northern Africa. At the father reaches, many places don't get a constant signal, but only occasionally as the satellites orbit overhead. However, the signal gets far too weak beyond the map above to be picked up by standard satellite radio antennas.
At the fringes?
Some of the mast-mount antennas have better gain (such as the Terk SIR-6 or the Directed 14240 outdoor mast-mount antennas - 42 dB gain, compared to 36 dB for most other car and home antennas). This can help a little, obviously along with antenna placement. This would likely be required, or at least helpful for constant service, in the areas at the limits of the pink area above. Beyond that, the signal is simply too weak for satellite radio antennas. You might be able to get a signal with a satellite dish. The Directed DBS splitter/combiner can connect an EchoStar dish to a Sirius radio. However, for it to be truly useful you'd need to have it track the satellites. Good luck with that...
This coverage map does not reflect the terrestrial repeater coverage - the signal around most major metropolitan regions in the U.S. is much stronger due to the repeater network. A repeater is a ground-based broadcasting station. A repeater's signal coverage appears to be stronger than the standard satellite signal with approximately a 20 mile radius.
The selection between picking up the terrestrial or satellite signal is automatic, and the radio will pick up whichever is significantly stronger. You can see whether your antenna is connected to a repeater by going into the radio's menu, selecting "antenna aiming", and seeing the two bar sets. The one marked "T" or "Terr" is the terrestrial repeater signal. If that is around one bar, it would probably be best to aim your antenna towards the nearest metro area to get the best signal.
Some people have a bit of trouble if they live on the edge of a repeater signal, where both the terrestrial and satellite signals are equally strong for much of the day. If this is the case, it would likely be a good idea to shield either the side or top of the antenna with something metal to allow it easily select one signal or the other. This is likely an issue that will be resolved with newer generation radios.
As you can see from their orbits, one might think that you can get Sirius service in South America. In most cases, as stated above, you can't. Another limitation on service for Sirius' system is the satellite uplink (what Sirius is sending to the satellites). The satellite uplink from Sirius comes from Vernon, NJ, USA. Because of the wide orbit of the satellites, the uplink signal can't reach the southernmost satellite at any particular time (this also means only two of the satellites are broadcasting any any particular time). The Sirius content can't reach the satellites very far past the equator, so there's no coverage much below that.
Also, it's interesting to note (at least for us) that Sirius' satellites do not actually orbit in a "figure 8", as is commonly believed. They orbit high above - much higher than suggest in these illustrations - in an elliptical pattern. That's just the shape of the signal they trace on the Earth (the "ground track").
What's Next? More satellites!
Sirius realizes its signal can be weak at times and that many listeners would appreciate a stronger, more consistent signal, as well as a wider range of services signal. Because of that, Sirius is considering launching a fourth satellite in 2008.
Sirius has a fourth satellite on the ground now as a backup in case one of the three in the sky suffers a catastrophic failure, so the next satellite would technically be the fifth. Launching that satellite would obviously be expensive (approximately $260M), but it would make the existing system more robust and cover many other areas. It would make them even more competitive with XM as well (it's worth noting XM is considering launching an additional satellite of their own). Additionally, Sirius can obviously survive on only three satellites, so if one fails in a constellation of four they could just rearrange them to the original positions.
If a fourth satellite is launched, the idea would be to have two satellites broadcasting and covering North America at any one time instead of only one. This next satellite is planned to use a more advanced signal broadcasting system to allow for great coverage and content capability. The fourth satellite is also planned to be geostationary, as opposed to the orbiting ones currently in the sky. This would provide far more consistent coverage and a stronger signal. Additionally, it would provide more consistent coverage to Central and possible South America as well as the Caribbean, so providing authorized service in those countries would be more realistic.
Also, Sirius is considering adding additional media and content to their service. There has been speculation and rumor about a Sirius video streaming service/device for a couple of years now. Sirius is launching video capability through their satellites, announced at CES 2007. It's called "backseat TV" and only has 4 stations right now. It's due to be released in Q3 2007, with the car model "SCV1", and a service cost of $19.99/month (which includes the radio service). The service is actually streaming now - it was live at the CES! They are all kid's stations now, and are meant to occupy the little ones in the back seat. It stands to reason that to support that for larger capability Sirius would need more bandwidth than is currently available. I doubt they'd limit the broadcasting to four kid's channels if they had another option. An additional satellite would likely make that possible. The next satellite would likely be largely devoted to the video content, and if so will revolutionize the satellite radio/TV industry. This is also part of the reason XM is considering an additional satellite. They currently have more limited bandwidth and technology than Sirius. An additional satellite would allow them to expand their service offering as well as coverage.
XM Satellite Radio
XM Radio coverage area is smaller than Sirius and static - its two satellites don't move and are designed to give the U.S. the best coverage. The below is the farthest reaches of the XM Radio coverage area, and the service will be very spotty at the edges:
Antennas for XM radio are best pointed to the South. As can bee seen in the animation above, the XM satellites are on both sides of the U.S., so the longitude of the aiming is not very important.
The angle of the XM satellites means XM often has a more vertical angle to many locations. This means the XM signal can have a harder time angling beneath bridges, trees, etc., and service can be intermittent. XM's repeaters are more numerous but weaker. The coverage area of the repeater network is similar at this point, but as Sirius expands its repeater network it will likely become stronger.
FYI: We've received report that XM radio can be received in Costa Rica with this [homemade] setup.