Radio Frequecies

Propagation of Broadband along telephone cables involves radio
frequencies.

This question is related to why the relatively short length of wire in
your house, between the long phone cable and equipment appears, in
some cases, to affect reliability.

Why is it that the length of drop-wire from the top of a pole into
your premises has little or no effect?

Does anybody know, approximately, what are the highest radio
frequencies involved with Broadband? In MHz.
----
Reg.

on 09/07/2006 at 13:23:38 Reg Edwards wrote:

> Does anybody know, approximately, what are the highest radio
> frequencies involved with Broadband? In MHz.

50Khz - 1.1Mhz

--
"The computer can't tell you the emotional story.
It can give you the exact mathematical design,
but what's missing is the eyebrows."
- Frank Zappa

on 09/07/2006 at 13:23:38 Reg Edwards wrote:

> Does anybody know, approximately, what are the highest radio
> frequencies involved with Broadband? In MHz.

My last reply had old info, this may be of more use.
http://en.wikipedia.org/wiki/ADSL

--
"The computer can't tell you the emotional story.
It can give you the exact mathematical design,
but what's missing is the eyebrows."
- Frank Zappa

On Sun, 9 Jul 2006 12:23:38 UTC, "Reg Edwards"
<(E-Mail Removed)> wrote:

> Propagation of Broadband along telephone cables involves radio
> frequencies.
>
> This question is related to why the relatively short length of wire in
> your house, between the long phone cable and equipment appears, in
> some cases, to affect reliability.
>
> Why is it that the length of drop-wire from the top of a pole into
> your premises has little or no effect?

Because there's a lot more electrical noise inside the premises.

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On 09 Jul 2006 13:26:56 GMT, "We Are Devo!"
<devo.usenet<NOSPAM>@googlemail.com> wrote:

>on 09/07/2006 at 13:23:38 Reg Edwards wrote:
>
>> Does anybody know, approximately, what are the highest radio
>> frequencies involved with Broadband? In MHz.
>
>50Khz - 1.1Mhz
.....for ADSL.

ADSL2+ can use tones up to 2.2MHz, hence the possible speed increase.
(And IIRC, VDSL2 can use tones up to 12MHz but is only useful on very
short loops.)

In message <176uZD2KcidF-pn2-(E-Mail Removed)>, Bob Eager
<(E-Mail Removed)> wrote
>On Sun, 9 Jul 2006 12:23:38 UTC, "Reg Edwards"
><(E-Mail Removed)> wrote:
>
>> Propagation of Broadband along telephone cables involves radio
>> frequencies.
>>
>> This question is related to why the relatively short length of wire in
>> your house, between the long phone cable and equipment appears, in
>> some cases, to affect reliability.
>>
>> Why is it that the length of drop-wire from the top of a pole into
>> your premises has little or no effect?
>
>Because there's a lot more electrical noise inside the premises.
>


What about the electrical noise generated by motor vehicles with poor or
no suppression components on their electrical systems? Doesn't the n
metres of telephone wire hanging from the poles act as an aerial for
these transmissions?

[1] Albeit at different frequencies and power levels, my digital TV via
an aerial is affected badly when one of those fart sounding motor cycles
passes close by.
--
Alan
news2006 {at} amac {dot} f2s {dot} com

On Sun, 9 Jul 2006 18:59:50 UTC, Alan <(E-Mail Removed)> wrote:

> >Because there's a lot more electrical noise inside the premises.
>
> What about the electrical noise generated by motor vehicles with poor or
> no suppression components on their electrical systems? Doesn't the n
> metres of telephone wire hanging from the poles act as an aerial for
> these transmissions?
>
> [1] Albeit at different frequencies and power levels, my digital TV via
> an aerial is affected badly when one of those fart sounding motor cycles
> passes close by.

That interference tends to be spasmodic and I guess the error correction
can cope with it. But ADSL cables are often quite near more long-term
sources of interference, I guess...mains wiring, etc.
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On 9-Jul-2006, "Bob Eager" <(E-Mail Removed)> wrote:

> That interference tends to be spasmodic and I guess the error correction
> can cope with it. But ADSL cables are often quite near more long-term
> sources of interference, I guess...mains wiring, etc.

Twisting the pairs reduces the effect of interference, the twists
aid cancellation at the next twist. Which is why we use twisted
pairs for street cabling, and in general for high frequencies.
Unfortunately a lot of the pre and post war cable is still under our
streets, it's ok for phones, but rather a poor pitch (about 7-12ins
twist) for BB.
The speeds "Up to" would be a lot better with decent quality cable,
but Ian Valance was more interested in his salary and pension
than BB, so BT ended up by losing it's monopoly on the ducts and
cabling. If BT had used it's monopoly position to run fibre to the curb,
we would all be better off, and BT could have sold off a lot of
its smaller exchanges, which would have been a nice little earner.
But the other side of the coin would have been BT having a
monopoly and higher prices.

On Sun, 9 Jul 2006 21:57:17 UTC, (E-Mail Removed) wrote:

(snip anti-BT rant)

All of which has little or no connection with the topic under
discussion...
--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.broadbandbanter.com

On 9-Jul-2006, "Bob Eager" <(E-Mail Removed)> wrote:

> All of which has little or no connection with the topic under
> discussion...

Except that there are endless complaints here
about sync failures, many, or most, of which
are probably cable related problems.
IMHO the cabling we have isn't going to
deliver quality video, which FTC would have.