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  3. Re: Technical Demo turns political 2/26/1909 [Telecom]

Re: Technical Demo turns political 2/26/1909 [Telecom]

Around here the wooden poles are loaded down, to the > extent that some poles are "doubled", there is a second > pole alongside, apparently to help with the weight.

A more common reason for poles being "doubled" is unfinished pole transfers. When a pole owner (typically power) replaces a pole, it sets a new pole next to the old one; transfers its facilities to the new pole; "tops" the old pole (cuts the top off above the highest communications cable); and notifies the communications companies (CATV, telco, whatever). The comm companies are supposed to transfer their facilities to the new pole, then notify power so it can come back and remove the old pole.

This process frequently breaks down, and you can probably guess why.

Historically around here the lines were--top electric, > middle phone, lower cable.

Actually, it's top electric, middle cable TV, and phone in the lowest position.

That's the standard arrangement for joint poles everywhere in the United States. See "Joint Pole" in any recent edition of Newton's Telecom Dictionary. An expanded (if somewhat obsolete) version of the same definition is at

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> The electric lines do not appear to have changed, but the > rest of them are heavy. I don't know which kind they are.

Multi-pair telco cables are indeed heavy. To keep them from sagging, the supporting strand is placed under tension, sometimes several hundred pounds.

CATV cables aren't as heavy, so strand tensions can be lower. But they're usually placed under high tension ("fiddle-string tight") anyway to prevent sag.

They've also added buried FIOS cable.

Many polelines also support fiber-optic cables. Since all fiber cables have the same general appearance, they're usually labeled by a red plastic sleeve at each pole. The label indicates the owner and provides a contact number.

Fiber cables are usually placed above copper telco cables on poles.

Despite the load, it's still relatively easy to carry > phone and cable since they're low voltage.

It's not as easy as it looks.

Strands supporting phone and CATV cables have to be placed under tension so that they don't contact each other under extreme weather conditions. A severe ice storm, combining heavy icing and heavy wind, greatly increases the tension on the strands. But the strands still have to be placed under sufficient tension that they don't sag on hot summer days when high ambient temperatures and direct sunlight combine to heat them.

Electrical conductors have an even bigger hot-summer-day problem: high I-squared-R losses (all those air conditioners draw a lot of current). But that 30-inch-at- midspan spec shown in Newton's book still applies.

Sag calculations can be extremely complicated.

But there is a > big shortage of carrying capacity for very high voltage > power lines that interconnect generating stations. > Neighbors fight those lines out of health worries.

I think you mean substations.

Neal McLain

Reply to
Neal McLain
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Neal McLain wrote in news:49AD4076.1080503 @annsgarden.com:

With municipal fire alarm (and other city communications) next under electric, where such systems still exist.

Reply to
Paul

The phone lines were relatively high up, and when new cable lines were installed to provide cable TV, the only place for them to go was lower. Unless of course the whole pole was redone.

The problem is it's not just one cable, as there was in the old days. Now there are many cables. (Don't know who they belong to.)

[I think power generation and distribution is on-topic as it is a closely related public utility to telphones. What happens to one utility effects the other.]

No, I meant generating stations. Running power to homes from the substation is not a major problem. Running power to the substations from the generating plant is somewhat of a problem due to insufficient capacity. But the electric companies can usually install intermediate range lines without too much opposition.

The big problem these days is the national 'grid' and interconnections. The power grid was orginally designed and construction to provide backup in case of a generating station or system failure; other systems would sell power so as to avoid a blackout. These are the "high tension" wires on very high poles, usually on their own right of way.

But in recent years power became a commodity and is traded. Power distribution managers seek the cheapest power, regardless if it's home grown or imported from far away. That 'trading' puts a huge strain on the interconnections of the grid.

I don't believe the grid has much margin for error. that is, when power is needed, it is needed instantly, otherwise the overload demand will trip out breakers causing a mess. Presumably, power demands in the aggregate do not zoom up suddenly, but gradually as individual customers turn on stuff. Of course, when a major transmission line or generating station suddenly fails, that puts a significant dent in the grid, and the ripple effect is very nasty (as in the NYC power failure not long ago).

I always wondered if there was any feasible way to temporarily store power in such cases, to act as a buffer.

Also, I wondered how can re-start times be improved if a plant shuts down totally. If a power failure does hit, apparently it can take hours or even days to bring plants on line again.

Reply to
hancock4

In the late 1960's, I worked for Bell labs, and was in Williamsport, PA on business. I noticed that there were two and sometimes three CATV cables on the poles. A local Bell craftsperson explained that there indeed was three competing CATV companies. They did not operate on a franchise basis. The first company signed up a lot of people, and then raised their rates very high. A second company saw a businesss oppurtunity, constructed a distribution system, offered low rates, and took customers from the first. Then the second raised their rates, and the cycle repeated. I looked in the phone book Yellow Pages, and indeed there were three CATV companies listed.

Reply to
Richard

Back during the dot.com boom Providence almost got a second cable carrier, AB Cable.

Reply to
T

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