[mythtv-users] HDHomeRun(s)
Brian Wood
beww at beww.org
Thu Jan 14 19:16:02 UTC 2010
On Thursday 14 January 2010 12:04:04 pm Ben Kamen wrote:
> On 1/14/2010 12:52 PM, Brian Wood wrote:
> > Close, the upper end of frequency response of cable systems does keep
> > going up, and the reason is the additional services being carried, but
> > many digital services are carried well below the top end of the system,
> > especially the return (upstream) portion of cable modems.
> >
> > All that matters is the frequency response of the passive devices, the
> > word "digital" really means nothing, though it might be easier for the
> > installers to understand than an actual frequency rating.
>
> Right.
>
> Ultimately, all the "digital" services on the cable are delivered in the
> analog domain in an RF fashion.
>
> Interestingly, if they delivered CAT5e to your house and plugged right into
> an Etherswitch and gave you a special network tuner, I could see that as
> being more "digital" (even though the higher speeds of ethernet use an
> "analog domain" style of transmission to deliver the bits).
>
> Even now, HDTV still only consumes only 6MHz of bandwidth like the old
> analog stations did. http://en.wikipedia.org/wiki/ATSC_(standards)
>
> Cable systems have been going up no matter what.. digital or not. So as
> Brian mentions, it's probably easier to print "digital" on the silly thing
> than try to train some of these guys as to what "bandwidth" in terms of Hz
> (Hertz) really means.
But when the cable systems get up to 1.5 or 2.0 Ghz., the "digital" will have
no meaning at all, and just confuse the "expert technicians".
>
> I used to work in CATV (fixing old OAK TC56 STV's when I was 17 and our
> system was a staggering 450MHz!) and some of those guys should have never
> been given a crimper.
You young guys :-)
When I worked in CATV we had 12 channels, with a top end of 216 Mhz. (the top
of channel 13). We used "pressure taps" on .412" feeder cable, and still had a
few vacuum tube amplifiers in service.
The old 2-piece F connectors were crap even when installed correctly.
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