Satellite Radios and reception

[R4RandR]

I know a lot of you out there have joined the latest satellite radio craze (services from XM and Sirius). I currently have a Sirius Xact radio and have been using it on the bike for the past year. Overall it's nice to have, especially for news/weather updates and of course the music. But......There are times I lose the signal and it doesn't make any sense as to when/why. I can be on a flat road, clear skies or right on the side of a mountain or in a valley. I understand next to a mountain and losing signal (which is REALLY annoying) but why does it drop when my angle to the satellite stays the same, without any obvious obstructions? I used this unit in a car for a short period before mounting it on the bike and it would occasinally do the same thing.

I'm wondering if XM does this also? Anyone out there have XM with these problems? I don't know if it's my receiver, antenna mounting position, or Sirius? Currently the antenna is sitting on top of my clutch reservoir and I've tried it in other places too with the same luck.

I've googled subjects regarding antenna placement and satellite locations and learned that XM uses two stationary satellites over the equator and a good dosage of terrestial repeaters in major metropolitan areas. Siruis apparently has three satellites that have a strange orbit where two are over north america at any given time. Sirius also has terrestial repeaters but not as many as XM (I read that on the internet, so it must be true!)

Let me know your experiences on solid reception, service and receiver brand.

Thanks!

 

[jakfrost]

John, I have XM with my Garmin 376 on the bike and Starmate Sirius in the car and generally get pretty consistant reception, but have on occasion had the same concerns as you mention. Every now and then for no logical reason the signal fades or fails for brief (3-10 secs.) periods of time.
I do find generally speaking here at my latitudes in Canada I get more consistant reception with Sirius than XM, due I'm sure to the difference in satalite orbits as you mentioned.

Jim

 

[Stuff2c]

Could be your riding faster than the signal...you may need to slow down.

 

[BRADFORDBENN]

First of all in the interest of full disclosure, I am a business developer for Crown and we make an XM receiver, so I know more about XM then Sirius. However we did look at doing both brands very carefully and chose XM based on their subscriber base and the fact that they have a commercial subscription.

The statements you made about Geosynch versus non-synched satellites is correct. Also your comment about varying numbers of terrestrial repeaters is correct.

Here is the other difference, the memory buffer for each unit can vary. I do not remember all of the specs, not like it really matters the exact amount, but the minimum buffer size on the XM is bigger if I remember correctly. Of course each manufacturer can make a bigger buffer if they want. I know that we do. (For those of you who have some of the newer XM units with the pause feature, now you know how it works.)

The size of the buffer helps with avoiding drop outs.

Having said that, another item might be your ground plane, depending on your antenna it might require a ground plane, especially if it is magnetic. You may want to look at other antennas. I know that XM has a few versions, you want to loof for a through window or a plastic mount antenna as they do not need a ground plane.

 

[furman]

Sirius and Xact

I have the same set up with the Xact receiver. But I have the antenna monted behind the rear luggage rack on a metel plate. I have noticed that when I go on heavy tree lined road I will loose the signal. But besides that it seems to work pretty good.

 

[furman]

Sirius Set Up (antenna)

Antenna mount.