"Rich Wood" wrote in message
...
On 15 Jul 2004 03:37:05 GMT, Diamond Dave
wrote:

They have three satellites orbiting in a figure-8 pattern.

According to my engineering friends at SIRIUS and the big satellite
display just off the lobby shows only two satellites in use at any one
time. One is rotated out to recharge.

So, effectively, both services have two operating satellites. In
heavily wooded areas of New England overhanging trees block the signal
from both services. I suspect the same is true in the Pacific
Northwest where you're often driving in tree-formed tunnels.

Rich


Actually, Rich, I'm glad you brought this up again, since I wanted to comment on your
observations made a while ago. I finally had my Sirius radio (and the car it was in)
far away from its local haunts (back-and-forth to work), as my son and I took a trip
to the Downington/West Chester area to see his new choice of University (yeah, I
know...too much information). What I found was, more or less, the same issues you
have...on local roads, where tree coverage is thick and low, I'd get occasional
drop-outs. It never was an issue on major thoroughfares, since brush and trees are
cleared higher and further away from the road. And, since we'd been listening to the
same station for over 250 miles from our origin, I'll take the occasional drop-out
over having it gone entirely long before had it been conventional radio.

But on our way back, I was astounded to find that (as opposed to complete absence in
the tunnels on the turnpike) I had coverage after travelling only half-way through
the Squirrel Hill tunnels in Pittsburgh. Clearly Sirius must have a terrestrial
repeater here, most likely on the downtown side of the tunnel, as I can't explain how
this could be any other way, but I really hadn't expected that Sirius had gotten
around to attending to Pittsburgh just yet. I know that this doesn't address the
outlying areas such as where you are, but clearly the terrestrial links will be
dealing quite adequately with this issue in metropolitan areas.

And thanks for explaining how Sirius' satellite use works. This also means that,
were one of the birds to fail, they could probably continue operations relatively
unaffected, although clearly more delicately balanced between operational use and
keeping the birds in a position to do so.
--
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