In article , johnny-b-
says...

On Tue, 31 Jul 2018 16:33:30 +0100, Terry Casey wrote:

Strange - it only seems a very short while ago that we were rolling out
our initial 600bps broadband product in competition with 56kbs dial-up!

Typo? ITYM 600Kbps broadband service. :-)

Oops! Yes, 600kbps.


I *well* remember the time when NTL used the 'harmonisation' of the
128Kbps service to 150Kbps (quarter the speed of the 600Kbps which had
formerly been 512Kbps) to squeeze a disproportionate (exhorbitant!) 3
quid increase over the 15 quid a month I'd formerly been paying.

We were Bell Cable Media at the time (later Cable & Wieless
Communications) and didn't offer a lower speed than 600kbps


Mind you, during the past 15 years or so, that same basic
150Kbps service has now morphed via several free speed
upgrades into an 85Mbps service (only a paltry 5Mbps upload
speed though)

I've never had the need for blisteringly fast upload speeds
and I doubt that the average user does, either.

However, the reason for the lower upload speed is embedded in
history when CATV first started and upload requirements were
usuaally limited to STB and supervisory data comms.

Attainable bandwidths were also low - 300MHz in the mid 70s,
increasing to 450MHz by the mid/late 80s, then 550 - 600MHz in
the early 90s. The older networks were upgraded for the
ionitial digital roll-out, when a figure of 750MHz was chosen
for most networks.

By far the lion's share of this bandwidth was always for the
downstream channels, the return path initially being 5 -
30MHz, increasing later to 50MHz and then 65MHz.

When I was redesigning the RF distribution network for the
Vintage Wireless Museum, I wanted a decent Band I/III diplex
filter, which I managed to scrounge from VM.

As it came out of a large box of identical used 65/85MHz
filters, I surmised that the return path had again been
increased, probably up to 85MHz, meaning that the FM band was
no longer carried.

How widespread such changes have been, I have no idea. Bearing
in mind the large number of original cable operators there
were intially, all with their own design ideas and choice of
equipment manufacturer, uprading the networks on a national
scale must be quite a tall order!

I'm now on what was originally Diamond Cable and, although
I've worked on their broadband routers in the past, I've never
had any contact with the RF side of their network, so know
niothing about it but I've run some speed tests in the last
few minutes and getting about 85Mbps download and just over
12Mbps upload.
--

Terry

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