Direct TV and Direct PC ( Satellite Technologies )
Matthias Bannach, bannach@cs.sunysb.edu
There is little information available on this topic
in
WWW references :
| http://www.hynes.com/ |
World Xplorer Online ( commercial )
|
| http://www.directv.com/ | Direct TV ( commercial )
|
| http://fiddle.ee.vt.edu/courses/ee4984/reports.html
| Telecom Class in the Virginia Tech Reports on various topics
|
| http://www.direcpc.com/docs/home.html | Hughes Networks ( big in DirectPC )
HNS=Hughes Network Services
|
| http://www.quiknet.com/satellit.html | Another provided in DirectPC
( seem to be related to Hughes NS )
|
| http://www.dishmaster.com/direcpc.htm | Dishmaster ( commercial )
|
Direct TV
Technical Data :
- Number of available ( possible ) channels
- stationary : 150..200 channels
- mobile : 175 channel
- 18" dish ( has such equipment ) $600
-
- DMX ( digital music => 150 CD quality channels )
- each (of 3 ) Satellite has 16 120Watt transponders
- 24 Mhz tranponder bandwith
Direct PC Technology
Some would like to call it 'Turbo Internet' ( the
request part of it )
Basic Idea :
- dial up link running some kind of IP ( PPP/SLIP )
- requesting ( provider software ) files/data
- request is served from Satellite Uplink location ( they have
a 'really fast link into the internet') and upload the data to
the satellite -> to home ( your PC )
- 400kbps for data downlink
- special dish ( might merge with direct TV dish some time soon
) [ 21 inch ]
- ISA adapter with RISC processor that interfaces to the LNC
and filters out the packages that you are 'allowed' to receive
- DES encoding for data transfers
- COSTS : $800..$900 for equipment
- $16 for 30MB Internet/month + ticker services
What do you actually receive
- framed packages of requested internet data
- ticker services ( CNN, Financial Ticker, Sport highlights,
….. )
- MPEG movie streams
- regular ( scheduled information services )
- software updates etc.
Where does it pay of, whom do they target ?
( advantages and disadvantages )
- guaranteed bandwidth ( as long as there is enough space )
- scheduled services ( like daily updates and information services
)
- information on demand ( 'as it happens' )
- company wide teaching services ( scheduled trainings )
- software updates, scheduled company data distribution ( broadcast
)
- expensive end user equipment
- expensive single user costs ( bytes per $ )
- good for global data distribution ( 'try my software' )
- has high throughput and can be used for 'fast' transmission
- can reach virtually everybody ( no infrastructure needed )
- it is available today ( no startup period like xDSL or ISDN
etc. )
- all broadcast services can be supported