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tom tom is offline
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Default Increasing Cable TV signal strength

On 2/9/2012 10:34 PM, Michael A. Terrell wrote:

tom wrote:

On 2/9/2012 9:35 PM, Michael A. Terrell wrote:
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.



Very nice. We were much more constrained on the install I mentioned up
the thread a ways. The fiber was fed at E1 speed, which probably didn't
work it very hard.

We had an issue at one point.

This was a distributed proc/data system, one of the first. Each cabinet
was a standalone PBX. And you could make 126 of them look like one.
And each could survive on its own.

First fiber campus we'd done. Staggered cut to the new infrastructure.
Fun stuff.

At one point we had to do the cutover to the other large pice of the
system. Each end connected the fiber. 0 signal.

TDR from A end showed 700 meters from A end, 800 meters from end B.
Length from A to B is 1500 meters.

The work that occurred because of that was not fun. Had to go get the
guy doing fusion splicing.

Joy. Midnight trip to Pittsburgh with the salesman.

Actually it was fun. Not much traffic at night.

Landing pattern at 160mph in between DC9s into Pittsburgh at about
midnight. And they didn't like 160 at all. This was scary.

Quickest turnoff onto a taxiway I've ever experienced. Of course the
taxiway may not have been one. We didn't care.

tom
K0TAR