|   any takers on CATV bandwidth for digital signals? | estan
Apr 24, 2001 1:36 AM | | curious is ....
I just upgrade my cable boxes to digital...my incoming signal is supplying 2 TV's and a cable modem. The original wiring was standard issue RG8U solid copper with a copper braided shield from 15 years ago. All of the connectors have been replaced within the past 2 years...wires stripped back 6" and new crimpons
installed.
I was experiencing bandwidth problems with the cable modem and a lot of freeze frames with the digital TV boxes which even required frequent rebooting of the boxes.
We did some bandwidth tests and found that we were getting about 1/3 of the bandwidth that we should be getting. Called the cable company (Time Warner) and got to level 3 tech support and they sent out a tech with some pretty decent test gear. They came back with a report that stipulated that all of my problems were cable related and the RG8 that was ok for analog was not working for the digital signal. Had to rewire the whole place with 6U...
This is very interesting to me because now I get great performance from the cable boxes and especially from my cable modem. The cable modem is only 40 feet from the Time Warner junction box and a simple change from RG8U to RG6U has tripled my available bandwidth from the cable modem. This is substantiated with printouts from their test equipment and from our bandwidth tests done on our computers to our own UNIX servers which are co located a few miles from here. We were unable to get over 300kbs and now we are averaging 1.1mbs.
curious....? |
| I'm curious myself... | Resident Loser
Apr 24, 2001 11:37 AM | | ...Belden cable states RG8 to be Coax- 50ohm Transmission and Computer grade, RG6 Coax- Standard Analog and Video Cables. Impedance mismatch?
jimHJJ(...???...) |
| I'm curious myself... | estan
Apr 24, 2001 11:44 PM | | sorry it was late...meant RG-59...
that would definitely be an impedance mismatch
here's the scoop from Sesco on RG6...
Serial Digital Cable
In the near future, video technology cush as Component Wide-Screen and High Definition Television (HDTV) will require rates above 360 Mb/s. To provide for maximum performance in applications demanding higher frequency technology, Belden has a Low Loss Serial Digital coax.
This RG-6 construction (part number 1694A) provides 20% lower attenuation than traditional precision video cables at the current serial digital frequencies; and as much as 30% lower attenuation at 1 Ghz. This impoved performance allows for error-free transmissions over extended distances. |
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