The problem could be standing waves. I don't think any FSM is accurate
enough to detect that. First of all the cable modem requires a
specific frequency, but it also requires the sidebands. In some cases
standing waves can cause complete eradication of 400,0001 Mhz yet
barely affect 400.0002 and 400.0000 Mhz. If this happens the signal
strength is fine bit there is so much distortion in the modulation
that the signal is near unusable.

Remember reorienting the antenna to get rid of ghosts in a TV picture
or distortion in an FM signal ? It is the same thing. Standing waves
are very much like multipath in their effects on signal quality. Some
old FM tuners actually had a scope built in to display multipath. The
optimum signal would display pretty much a flat line. Moving the
antenna would cause dips in the line, and that is what causes
distortion. Measuring signal strength just doesn't cut it.

He may have been blowing smoke about the TVs polluting the signal.
It's hard to believe the effect would be a big problem if they meet
FCC requirements on radiation. But then it's possible that he was just
attempting to improve the signal as much as possible. Hard to say. I
know people get alot of lip service when what they want is service,
this one is tough to call either way. Maybe he just did what he
could.

But FCC requirements say nothing about antenna input impedance, if
that is off it can cause the standing waves. I'm not sure if a filter
would take care of that completely. It seems it should but I know
better, things do not always work as they are supposed to.

If you are talking a "thinner" cable than what is used tody it is
probably RG59 or RG59U, both of which attenuate the high frequencies
significantly. If the cables and the fittings are perfect this is
simply due to capacitance and is not likely to cause standing waves.
But then those things are not likely to be perfect, and may not have
been in the beginning.

The only way to tell really is with a sweep spectrum analyser, and
those things will not be on the truck due to cost. The cables could
also be checked for that using a time domain reflectometer, which
would be even better, but look up the cost of one and you'll see why
there was not one on the truck. It's simply too expensive.

It is possible that it is the cables, and you don't need a licensed
electrician for that in most localities because there is no power
involved. But finding someone who really knows how to hide the wires
is not easy. Most higher caliber electricians can do it but they
usually simply refuse because it is a ballbuster. I can do it, but
unles you live nearby it is not going to happen.

Do your neighbors have this problem ? If not get them to run a line
straight into your existing cables and see if the problem persists. It
will have to be attenuated to the same level you have now to make it a
valid test. If it is found to be in the wiring in your unit, which can
only be proven by others in the same complex using the same modem,
with a couple of other requirements, it may be a matter of fishing a
new cable into wherever it splits off into your unit. It is very hard
to be absolutely sure, and the shotgun approach may be a better idea -
which is to replace all the cables in your unit.

Now is another factor, there is more than one carrier frequency
involved in cable internet distribution. These two modems might work
on different frequencies, and due to the nature of the effect of
standing waves that can make all the difference in the world. So now
the question is, since they got you hooked up with the other modem,
why not just leave it that way ? Is there a rational explainaition for
that ? They may have reasons we may never know, but it seems to me if
they want that check every month they should do whatevwer it takes.

So my highly technical ass with all the experience has this advice -
Tell them to take their service and shove it up where, well make sure
it doesn't get a sunburn. Tell them the wires are fine with the old
modem, why change it ? Tell them you are considering other options and
since they can't provide what you are paying for the contract is null
and void - they are in breach. You should see some action.

See to them it's not just the monthly check, it's market share.
Therefore threatening to quit works wonders. Got someone I know a free
wireless router a few months ago, but she is sharp. Not when it comes
to computers, but when it comes to money. She was head of the
purchasing department before she retired and she gets things done.
Threatening to do business elsewhere has alot more impact to companies
like this than one might think. Having more customers does alot, it
can affect stock prices, the D&B rating as well as their advetising
plans. Use it against them if they don't deliver the goods.

J