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Message Digest
Volume 28 : Issue 75 : "text" Format
Messages in this Issue:
Re: under-sea power transmission cables
Re: under-sea power transmission cables
Western Union public fax services, 1960
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Date: Mon, 16 Mar 2009 18:13:57 +1100
From: David Clayton <dcstar@myrealbox.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: under-sea power transmission cables
Message-ID: <pan.2009.03.16.07.13.55.777591@myrealbox.com>
On Sun, 15 Mar 2009 12:12:14 -0400, David Kaye wrote:
> On Mar 12, 10:07 am, Will Roberts <oldb...@arctos.com> wrote:
>> Following up on the discussion of underground high-voltage power
>> transmission lines, it's worth noting a project which was under
>> consideration in Hawaii.
>
> I'm wondering how safe it is to transport high voltages through bodies of
> water. I realize it happens in the Bay Area (the cable that replaced the
> Hunters Point power plant, for instance), but does anybody know how safe
> this practice is?
>
> I know that rats are drawn to electric cables, which is apparently why
> there are so many electrocuted rats who have eaten through cables. I'm
> wondering if there is any other danger from running high voltages through
> water.
>
The DC cable between Victoria and Tasmania was originally going to use the
sea as the "return" conductor, but there were oil rigs in the vicinity and
they kicked up a (justified) fuss about electrolysis corroding the rig
structures, so the line ended up being dual conductor with both insulated
from the environment (AFAIK).
I'm assuming all these long cable runs are now DC to maximise the overall
power that you can pipe down these things - all built on the back of
super-efficient AC to DC conversions at either end. That might keep
"bitey" things away from the cable rather than an AC field.
--
Regards, David.
David Clayton
Melbourne, Victoria, Australia.
Knowledge is a measure of how many answers you have, intelligence is a
measure of how many questions you have.
------------------------------
Date: Mon, 16 Mar 2009 07:35:21 -0700
From: AES <siegman@stanford.edu>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: under-sea power transmission cables
Message-ID: <siegman-341666.07345116032009@news.stanford.edu>
In article <rv7rr456vm8n0ds78b86ji23omb80mkin3@4ax.com>,
Eric Tappert <e.tappert.spamnot@worldnet.att.net> wrote:
>
> With that adaptation, the major problem with undersea communications
> cables these days is fishing trawlers snagging the cable.
>
Or, newer fiber optics cables and technologies coming along which have
so much more capacity that it no longer makes sense to continue using
the only slightly older versions, and they're simply abandoned in place
on the ocean floor, long before the end of their useful life (or are
converted into serving undersea observatories).
(At least it's my understanding that this has happened with at least
some transoceanic cables.)
------------------------------
Date: Mon, 16 Mar 2009 19:42:57 -0700 (PDT)
From: hancock4@bbs.cpcn.com
To: redacted@invalid.telecom.csail.mit.edu
Subject: Western Union public fax services, 1960
Message-ID: <bf7b6b49-7092-4a8e-873e-f81c9e54bd1d@z9g2000yqi.googlegroups.com>
Per our recent discussion on Western Union services, I found some
information about Western Union's public facsimile services.
Western Union ran several advertisments in the New York Times for its
public "wirefax"/"telefax" service. I found ads for 1959-1962.
The maximum size of a document was 8.5" x 11", and the transmitted
portion was roughly 1" shorter on all sides (7.5" x 10").
Transmission took five minutes.
The service was offered in New York City, Washington DC, Chicago, Los
Angeles, and San Francisco. In the time span I checked no additional
cities were added.
The material had to be taken to a Western Union office. WU would pick
it up at an additional charge for their messenger. It would be
delivered by Western Union messenger without charge to any place
within the city limits of the destination city.
The first 4" vertically between NYC and Chicago cost $2.40 and 40
cents for each additional inch. plus Federal tax. The first 4"
between NYC and San Francisco cost $4.00 and 65 cents for each
additional inch plus Federal Tax.
So, a full page letter (with margins) to Chicago would cost about
$3.60 per page, to San Francisco would cost about $5.95 per page, both
plus Federal Tax (10%?), in 1960 dollars, plus the expense of delivery
to the central WU office. By today's dollars that seems quite
pricey.
An engineering drawing would probably be larger than regular office
size and need to be cut up for transmission in multiple pages. Legal
contracts are usually multiple pages. Thus, a typical business
document would be very expensive to transmit. Given that high price I
can't help but wonder if a business might be willing to wait a day or
two for air mail and special delivery, at a fraction of the cost.
Other alternatives might be a Night Letter telegram or a Telex/TWX
message. The business world moved a bit slower in those days*.
I presume there was some sort of air express service by 1960, but I
have no idea what they'd charge for a small package back then. I
believe Railway Express Agency (REA) offered expedited shipping on the
fast overnight trains between New York and Chicago (eg the Twentieth
Century Limited), but again I don't know the charges.
Certain documents would not be faxed such as photographs, or legally
prohibited, such as drug prescriptions, naturalization certificates,
legal tender, etc. I could understand prohibiting legal tender, but
drug prescriptions and naturalization certificates are the kind of
documents a traveller might need transmitted in a rush.
--NYT, 12/3/1959, display ad.
*I am amazed that anyone can sit at their desk today and, at no
charge, receive stock quotes, stock history, and current analysis
from many newspaper websites; that information that once was only
available in a stockbroker's office to regular customers.
Stockbrokers used the Western Union "900 speed" ticker to keep up.
The Bunker Ramo company had stock-lookup computer terminals in the mid
1960s.
[public replies, please]
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