[time-nuts] Sun Outage
W4wj at aol.com
W4wj at aol.com
Fri Oct 10 17:23:38 EDT 2014
Andy...
On DirecTV and Dish, in order to get channels beyond the basic package,
Dish and Direct both use additional satelites at different orbital
locations.
If you have only the basic package, you get one antenna and possibly only
one feed horn.
Dish for example can use a two antenna setup. The main antenna could
have a dual feed horn that looks at two different satellites at 110
degrees W
and 119 degrees W. Then the second antenna would have a single feed
horn looking at either the satellite at 61.5 degrees W or 148 degrees W.
The 110 and 119 satellites can be viewed from the east coast to Hawaii.
The 61.5 satellite can be seen from the east coast to west Texas. The
148 satellite can be seen from west Texas to Hawaii.
It would not be uncommon to have rain fade on one satellite and not
on the others!
Here is a list of some of the DishNetwork channels with their channel
number and satellite assignment(s)
http://www.alanthompson.com/dish-network-satellite-tv-channel-listings.asp
Note that other than the ABC/CBS/NBC/Fox stations on channels
241-248, the local stations that you would normally watch, unless they
are in SF or NYC, are not listed, but they are being carried on "spot
beams" from one of the satellites.
It is quite a "shell game" to fit all the feeds into the bandwidth
available,
and then instruct the receiver as to the frequency, polarization and
satellite location for a particular channel.
73
Don
W4WJ
In a message dated 10/10/2014 1:34:34 A.M. Central Daylight Time,
AI.egrps+tn at gmail.com writes:
Bob Stewart <bob at evoria.net> wrote:
... Also, the cartoons I was recording for my granddaughter were
> unaffected, but the station I was watching had the outage. That doesn't
> all fit together unless it was the uplink that had the problem.
I don't think the uplink itself can have this problem.
But DirecTV uses multiple transponders per satellite, and in some cases
more than one satellite, so all the channels are not affected equally.
When I had DirecTV, we had two dishes. The installer boggled up the first
install so they came back and put up another one several feet away, mounted
on a more stable surface (not roof shingles). The first dish was one that
could be used for multiple satellites. It had three 'focal' points with
three little radomes that either had, or could have, LNAs in them. Each
points to a different spot in the sky. The second dish had only one.
Regardless, we received only one satellite.
I don't recall ever being affected by a solar outage, but rain and ice were
real killers! Yeah they say rain shouldn't cause an outage, but it does
when the rain density is high enough. I could use that to predict when we
were about to be hit by a downpour. There was about a 3 minute lag
between
losing all the channels, and the downpour starting.
It occurred to me that one could use satellite signals as a meteorological
instrument to measure the water density in the atmosphere above you. I
wonder if the NWS does that.
Andy
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