tom wrote:
On 2/9/2012 9:35 PM, Michael A. Terrell wrote:
Grow up. That is an excessive length drop. A standard drop is under
100 feet. You think you know everything, and that the world has to live
by your rules. You don't, and it doesn't. I'll bet you've never even
seen a CATV franchise, or the dozen of pages of specifications agreed to
by both the CATV company and the local government. The CATV company
isn't a Santa Clause machine, and local governments know why there are
limits to the service provided. If there were't, no one could afford to
build or operate a CATV system. You've never designed a headend, or a
physical plant If they build to supply higher port levels, it has to
start at the headend, and requires closer spaced trunk amplifers. The
system noise goes up from all of the cascaded amplifers, and the
equipment runs hotter, withj a very reduced service life. When you can
design an RF distribution system of more than 500 MHz bandwidth and has
over 10,000 output ports, with the gain stabilized to a couple dBmv 20
miles from the headend and over a range from sub zero F to + 100 F then
you can tell me I'm wrong.
One headend I designed and built was only off by .1 dBmv at the test
port on the first trunk amp which was a half mile from the head end. If
you can do better than that, I'll listen to you and your opinions
Cool! You seem to know what you are up to.
Can you put rough numbers around what you mentioned? Like what are
providers legally required to deliver at the far end of the drop?
We were required to deliver 0 dBmv at the end of 100 feet of RG-59 or
RG-6 for two sets per the franchise. The system was designed at +10
dBmv at the tap to allow for three or four TVs at the 100 foot range.
That was on a 36 channel system with RCA modulators & HST. It was done
for two reasons. To have a little extra signal available when the
system was built, and for conversion for a 300 MHz plant to a 450 MHz
plant without respacing the trunk amplifiers.
I build a headend & interface to tie two incompatible community loops
together. Ours was a sub split loop, and the other CATV company used
mid split. We used 2 & 12 for pilots, so we fed them Channel 2 into
their return, and down converted their feed to T-9 for our return. That
headend had two RCA HSP and a combiner. The interface was another HSP
in a large stainless steel NEMA box mounted to a power pole at the
boundary of the two systems. A pair of two way splitters were used to
route the signals between the systems, as well as into and out of the
HSP. The other company wanted us to install a modulator and a
demodulator at the boundary to give us audio & video, and another pair
from our side so the interface would be baseband. Their design was over
$15,000 in hardware alone. My design was under $3000 for all the
hardware & labor to install. I had system designers from both sides
telling me it wouldn't work, but it did the job with no problems.
--
You can't have a sense of humor, if you have no sense.