[Gllug] [slightly ot] ADSL config fun

[Chris Bell]

On Fri 20 Sep, John Hearns wrote:
> 
> On Fri, 2002-09-20 at 12:30, Chris Bell wrote:
> > On Fri 20 Sep, Mark Lowes wrote:
> 
> >    I understand that one of the reasons why BT appear to have dragged their
> > feet in the past was the requirement that any telephone should work in an
> > emergency without any local power as long as the wires were still intact.
> > This is still true with most analogue phones even if they are normally mains
> > powered.
> >    Many of the lines I worked on were just that, a chain of bits of wire
> > joined together for a few days, often without line power or repeaters, so we
> > had to supply our own line power and ringer supplies, and needed to shout if
> > we were some distance from the other end. If we were very lucky there might
> > be some spare capacity at the local exchange to give us a standard phone as
> > well, but that cost a 1 year rental each time. We often had to search for
> > the end of the cable, left in a convenient hedge or tree. We usually have
> > our own PBX now, linked with a mobile phone unit, with the main output going
> > by satellite because it is cheaper to set up each time.
> 
> OK. You've got us interested. Just what exactly were you up to? 
> My guess territorial army - how far off am I?
> 
> 
> 
   BBC TV outside broadcasts, hence the silly things we had to do in silly
places at silly times. As an engineer you were expected to be able to do
almost anything at any time. We worked part of the time in the test rooms
doing maintenance, and part of the time on the road. Most of the time I was
a vision engineer, looking after and operating equipment in a mobile control
room, but I also did some time with communications department, setting up
temporary links.
   There was a famous occasion when a music circuit back to London was
divided into three frequency bands and sent down three parallel circuits. A
man with a digger cut through the mid frequency circuit, leaving an easily
recognisable voice with absolutely no intelligence.
   I spent a couple of days in mid winter parked outside a (then Post
Office) communications tower on top of the Pennines as the receive end of a
BBC link. We passed the good quality signal to the permanent link, but the
local engineers forgot to tie down the relay change-over to the reserve
link. There was some intermittent interference which kept making the relay
rattle, causing no problem with their normal traffic, but carving up our
signals completely, and we were nearly attacked by their deranged cleaner
when he turned up for work. He had told us the day before as he went off
duty that he wanted to watch the programme.
   If anyone is interested, they may be selling off their first satellite
dish soon. It is a trailer mounted four metre dish, with enclosed cupboard
space for the electronics. It could only be used as the starter end of a
link to Goonhilly at first, so the signal was mangled by the time it arrived
back in London. The person who specified it doubled the transmitter power
from what he thought was needed, but so did every level of management above,
so by the time it was built it could almost set fire to a brick wall. The
original electronics has been replaced since.

-- 
Chris Bell


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