[Tfug] modem and router combo

[christopher floess]

On 10/27/07, Ronald Sutherland <ronald.sutherland at gmail.com> wrote:
> On 10/27/07, christopher floess <skeptikos at gmail.com> wrote:
> >
> > > Christopher is there any chance your cable modem is getting hot
> >
> > Actually that seems like it MIGHT be an issue. I noticed the
> > other day that I was dl'ing at an unprecidented speed. I
> > actually have their low level service (I think it's supposed
> > to top out at 256k), but I was way faster than that. But I
> > wonder how fast you have  to be for heat to start becoming
> > an issue b/c my modem is in a very well ventilated place.
> >
> >
> Downloading should not work the RF amplifier much (only sending), so little
> heat from that...
> It all has to do with how much current the amplifier has to push into the
> cable to change the potential.
> Adding impedance reduces the amount of current to get to a desired potential
> (voltage level), although after the impedance the level is even lower. Every
> data bit that goes out of the modem is a finite amount of current from the
> RF amplifier, and that current heats the amplifier. The amplifier is tied to
> a thermal sink, a reservoir for heat that also spreads the heat out and
> moves it to ambient (where your ventilation helps). The rate that heat moves
> to ambient is often less than the rate heat is added by the amplifier at
> high transmit rates so heat builds up until a thermal sensor trips that
> shuts down the amplifier (indeed a good calculus problem).
>
> I hope the cable installer person can find the problem, since they need to
> set the system up so it does not go into thermal shutdown. I'm starting to
> think that adding impedance may be a common fix. Also as connections are
> made to the cable its reactance will change so the amount of heat will
> change. The good news is that every house gets a splitter signal which
> limits the effects of one user on another, for example if some next door is
> shorting the cable TV to keep the kids out of the house.
>
> 256k sounds like low DSL? Throttled data rates are done by buffering data or
> resending data packets, both cost them extra, everyone should request the
> low speed >:-)

russian, russian, and then some more russian. I just don't stop
being amazed at all the stuff people on this list know. I guess
in a way that's what I'm here for. But really, I got on to get in
touch with what people know about *nix. I knew I'd get
schooled about that stuff, but that's how you learn, you get in
touch with people doing the stuff you like but have done it
longer or know it better, etc. But sh*t, I've read some stuff on
this list that just makes me realise that yah, the crap you learn
in college really is useful in some ways.

Hopefully I'll be able to follow some of the stuff you just wrote
some day, but until then, keep throwing it my way b/c it can
only bounce off for so long before I start absorbing it :)

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A: Make me one with everything ~ Dr. Jonathan Katz