[clue-tech] Line noise and modem hangups

[F.L. Whiteley]

Have you spoken to the radio station antenna guy?  I had some issues here in
Greeley with a Windsor based station transmitting off frequency.  Corrosion,
bad grounds, bad connections, or wave guide problems can cause RF leaks into
the antenna structures and every nut and bolt and strut can 'cut' a variety
of frequencies and harmonics leading to this type of interference.  In the
UK, one of our 10K USAF HF transmitters blanked out VHF air traffic control
frequencies for a 150 mile radius each time it was keyed. This was due to
corrosion between one element and the wave guide which meant the RF leaked
down the 110ft tower. In another case a USN HF radio harmonic was
interfering with the unfiltered AM luminosity playback frequency of a VHS
VCR while it was connected to the satellite receiver.  The person could
record okay, but viewing was bad due to a bright streak blocking 50% of the
display.  We suggested he contact the satellite receiver guy about filtering
that system.  I run into about a half a dozen connectivity problems each
year due to electric fences (with bad grounds or brush) 'sparking' noise
into the phone lines.  Most of these are temporary fences while cattle and
sheep are in the corn fields.  After about 10 re-trains, the modem
disconnects, which may be what you are seeing.  Fixing the fence does the
trick.

Personally, I would complain to Qwest that the radio noise is interfering
with your ability to carry on a coherent voice conversation on the phone
line and you want the interfering noise off of your line.  That should get
the problem solved at no charge.  Qwest does not charge for repair calls
that are demonstrably upstream of the demarc.  Had a recent case where the
tech had to remove some bridge taps to stabilize service to a DSL customer.
DSL is unregulated, but voice is and I have yet to seem them balk at fixing
noise issues when it affects your voice service.  Some spectrum analysis of
the radio stations might reveal problems, but it might be easier to ask your
neighbors if they are experiencing the same noise.  If not, it puts it
squarely back into Qwest's lap.

Frank Whiteley
Greeley

> -----Original Message-----
> From: clue-tech-bounces at clue.denver.co.us
> [mailto:clue-tech-bounces at clue.denver.co.us]On Behalf Of Doug Williams
> Sent: Monday, June 27, 2005 9:19 PM
> To: CLUE technical discussions - Q&amp, A
> Subject: Re: [clue-tech] Line noise and modem hangups
>
>
> Nate,
>
> I determmined that it was coming from the outside by
> hooking up a phone directly to the network beyond the
> box and was getting either KOSI or KEZW crystal clear
> from the phone. I pointed this out to QWest and they
> told me that unless I get DSL they will do nothing for
> me. I also can use another computer here in the house
> that has a Winmodem and connect at least at 34k and
> not drop the connection until I am finished with the
> session. I have moved the computer to other rooms
> thinking that it might be the proximaty to an alarm
> switch box in the house but that is not it. I can
> connect on occasion near 32 or at slowest 29k but I
> have to hit the right time of the night and right day
> of the week to do it. I am just getting tired of
> hearing elvis if I use an internal modem on the phone
> I connect to it and not having a reliable connection
> to the internet.
>
> Doug
>
> --- Nate Duehr <nate at natetech.com> wrote:
>
> > Doug Williams wrote:
> > > Hello,
> > >
> > >  I live in Centennial near the KOSI radio towers
> > and I am having problems with line noise cutting me
> > off when I am trying to use dial up on my computer
> > with either SUSE or (unfortunately)Windows XP. I am
> > using an external USR V92/fax modem I thought that
> > it might help me connect as I have had good results
> > with external modems before, but not now. I have
> > talked with local side of QWest to no avail as they
> > won't help home customers who don't use their DSL
> > service. I was wondering if anyone else has had this
> > issue or lives in the Centennial area near Arapahoe
> > and Colorado Boulevard and has any suggestions short
> > of going to DSL or a cable modem. I have tried using
> > the rfi filters that you can get at Radio Shack with
> > the same results. I also tried the advice of someone
> > who works at a Radio Shack and is a SUSE user and
> > added a shielded connector cable from my computer to
> > the wall but still getting noise hangups.
> > >
> > > Thank you for any help
> > >
> > > Doug Williams
> >
> > Hi Doug,
> >
> > How do you know it's line noise cutting you off?
> > Your neighborhood
> > could be serviced by a SLIC or similar muxing
> > device, and thus
> > un-friendly to analog modem service.  Can you hear
> > KOSI on your phones?
> >
> > If so, unplug ALL of your phones except the modem
> > and see if the problem
> > goes away.  Something is bringing the RF into the
> > audio frequency range,
> > and it may not be the modem -- you could have a
> > cheap phone acting as a
> > receiver.
> >
> > There's a number of other things to check, but
> > that's the simplest to
> > start with.
> >
> > If you have a modular demarcation point outside your
> > home (one of the
> > newer ones with an RJ11 jack) you can put a
> > male-to-female adapter in
> > and make a call right there at the outside service
> > entrance...
> > especially if you can borrow a laptop and keep the
> > cables short (so they
> > don't act as antennas).  If the problem exists even
> > during that test,
> > there's probably little you can do about it.
> >
> > Qwest should at least be willing to provide you with
> > the results of an
> > automated test done by a technician at the demarc
> > outside your home.  If
> > there's no problem found, they could charge you for
> > the site visit, though.
> >
> > Other things that can be done... you can buy phone
> > cables with ferrite
> > beads already installed on each end (sometimes you
> > see Ethernet cables
> > for laptops come with these also, so they'd pass
> > their spurious
> > emissions tests).  They sometimes can help in high
> > RF environments.
> >
> > Nate
> > _______________________________________________
> > CLUE-tech mailing list
> > CLUE-tech at clue.denver.co.us
> > http://clue.denver.co.us/mailman/listinfo/clue-tech
> >
>
>
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