Radio Control interference to FTTC

Yesterday afternoon the kids in a family in our street were playing
with a radio controlled car. I noticed them out of the window of my
home office. The next thing I noticed was that my FTTC modem's DSL
light was flashing as it had lost sync. It regained sync when they
paused for a short while, only to lose it again when they continued
driving the car around. The one with the transmitter happened to be
standing right under the wire from the telegraph pole to our house,
and also directly above the underground conduit to the pole.

Once they had finished and gone indoors, the line regained sync and
stayed up. I assume the (presumably) 49MHz signal was getting picked
up by my phone line (or perhaps the modem) and was to close to, or
overlapping with, the VDSL signal.

Not sure there's much I can do about it apart from hope the batteries
run down quickly :-) but I'd be interested in anyone's comments.

Cheers
Tony
--
Tony Mountifield
Work: (E-Mail Removed) - http://www.softins.co.uk
Play: (E-Mail Removed) - http://tony.mountifield.org

Tony Mountifield wrote:

> Yesterday afternoon the kids in a family in our street were playing
> with a radio controlled car.
> Once they had finished and gone indoors, the line regained sync and
> stayed up. I assume the (presumably) 49MHz signal

R/C for surface models should be 40-41MHz, though it could use the ISM
frequencies 433MHz or 2.4GHz, but those would be more likely to
interfere with your car's central locking or WiFi respectively.

> was getting picked
> up by my phone line (or perhaps the modem) and was to close to, or
> overlapping with, the VDSL signal.

VDSL tops-out at 12MHz, I've never inspected an openreach service
specific faceplate for FTTC, but I'd expect they have a low-pass filter
that would cut out signals significantly above that point,

In article <(E-Mail Removed) >,
(E-Mail Removed) (Andy Burns) wrote:

> R/C for surface models should be 40-41MHz, though it could use the
> ISM frequencies 433MHz or 2.4GHz, but those would be more likely to
> interfere with your car's central locking or WiFi respectively.

or 27MHz...

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981

"Tony Mountifield" <(E-Mail Removed)> wrote in message news:j20e14$10g$(E-Mail Removed)...
> Yesterday afternoon the kids in a family in our street were playing
> with a radio controlled car. I noticed them out of the window of my
> home office. The next thing I noticed was that my FTTC modem's DSL
> light was flashing as it had lost sync. It regained sync when they
> paused for a short while, only to lose it again when they continued
> driving the car around. The one with the transmitter happened to be
> standing right under the wire from the telegraph pole to our house,
> and also directly above the underground conduit to the pole.
>
> Once they had finished and gone indoors, the line regained sync and
> stayed up. I assume the (presumably) 49MHz signal was getting picked
> up by my phone line (or perhaps the modem) and was to close to, or
> overlapping with, the VDSL signal.
>
> Not sure there's much I can do about it apart from hope the batteries
> run down quickly :-) but I'd be interested in anyone's comments.
>
> Cheers
> Tony
> --
> Tony Mountifield
> Work: (E-Mail Removed) - http://www.softins.co.uk
> Play: (E-Mail Removed) - http://tony.mountifield.org

You are understandably assuming that the radio transmitter is causing the interference, but
that's unlikely given the likely frequencies involved.
It's much more likely to be the car itself, specifically its brush motor.

How far away are you from the FTTC cabinet?

--
Graham.

%Profound_observation%

In article <(E-Mail Removed) >,
Andy Burns <(E-Mail Removed)> wrote:
> Tony Mountifield wrote:
>
> > Yesterday afternoon the kids in a family in our street were playing
> > with a radio controlled car.
> > Once they had finished and gone indoors, the line regained sync and
> > stayed up. I assume the (presumably) 49MHz signal
>
> R/C for surface models should be 40-41MHz, though it could use the ISM
> frequencies 433MHz or 2.4GHz, but those would be more likely to
> interfere with your car's central locking or WiFi respectively.
>
> > was getting picked
> > up by my phone line (or perhaps the modem) and was to close to, or
> > overlapping with, the VDSL signal.
>
> VDSL tops-out at 12MHz, I've never inspected an openreach service
> specific faceplate for FTTC, but I'd expect they have a low-pass filter
> that would cut out signals significantly above that point,

Interesting, thanks. I'm on friendly terms with the family, so if it
starts to happen frequently, perhaps I'll arrange to do a little diagnosis
with them, to pass on to the Openreach bods via my ISP.

Cheers
Tony
--
Tony Mountifield
Work: (E-Mail Removed) - http://www.softins.co.uk
Play: (E-Mail Removed) - http://tony.mountifield.org

In article <j20gth$9oo$(E-Mail Removed)>,
Graham. <(E-Mail Removed)> wrote:
>
> "Tony Mountifield" <(E-Mail Removed)> wrote in message news:j20e14$10g$(E-Mail Removed)...
> > Yesterday afternoon the kids in a family in our street were playing
> > with a radio controlled car. I noticed them out of the window of my
> > home office. The next thing I noticed was that my FTTC modem's DSL
> > light was flashing as it had lost sync. It regained sync when they
> > paused for a short while, only to lose it again when they continued
> > driving the car around. The one with the transmitter happened to be
> > standing right under the wire from the telegraph pole to our house,
> > and also directly above the underground conduit to the pole.
> >
> > Once they had finished and gone indoors, the line regained sync and
> > stayed up. I assume the (presumably) 49MHz signal was getting picked
> > up by my phone line (or perhaps the modem) and was to close to, or
> > overlapping with, the VDSL signal.
> >
> > Not sure there's much I can do about it apart from hope the batteries
> > run down quickly :-) but I'd be interested in anyone's comments.
>
> You are understandably assuming that the radio transmitter is causing the
> interference, but that's unlikely given the likely frequencies involved.
> It's much more likely to be the car itself, specifically its brush motor.

That's quite possible too, I guess! Easy to test for - just use the
transmitter with the car switched off.

> How far away are you from the FTTC cabinet?

About 500 to 600 metres. Normal BRAS is about 24M, but it's now dropped
to 19M.

Cheers
Tony

--
Tony Mountifield
Work: (E-Mail Removed) - http://www.softins.co.uk
Play: (E-Mail Removed) - http://tony.mountifield.org

On Thu, 11 Aug 2011 12:52:03 +0100, Andy Burns wrote:

> R/C for surface models should be 40-41MHz,

Isn't 27MHz used any more? Pretty sure my old (as in around 15 years
old) RC model car uses 27MHz.

>> was getting picked up by my phone line (or perhaps the modem) and
was
>> to close to, or overlapping with, the VDSL signal.
>
> VDSL tops-out at 12MHz,

IIRC the signal from a RC transmitter isn't particularly "clean" it
could well be putting out significant amount of noise in the VDSL
band that is getting picked up by the overhead line and messing
things up.

--
Cheers
Dave.

"Tony Mountifield" <(E-Mail Removed)> wrote in message
news:j20h9l$2fh$(E-Mail Removed)...
> In article <j20gth$9oo$(E-Mail Removed)>,
> Graham. <(E-Mail Removed)> wrote:
>>
>> "Tony Mountifield" <(E-Mail Removed)> wrote in message
>> news:j20e14$10g$(E-Mail Removed)...
>> > Yesterday afternoon the kids in a family in our street were playing
>> > with a radio controlled car. I noticed them out of the window of my
>> > home office. The next thing I noticed was that my FTTC modem's DSL
>> > light was flashing as it had lost sync. It regained sync when they
>> > paused for a short while, only to lose it again when they continued
>> > driving the car around. The one with the transmitter happened to be
>> > standing right under the wire from the telegraph pole to our house,
>> > and also directly above the underground conduit to the pole.
>> >
>> > Once they had finished and gone indoors, the line regained sync and
>> > stayed up. I assume the (presumably) 49MHz signal was getting picked
>> > up by my phone line (or perhaps the modem) and was to close to, or
>> > overlapping with, the VDSL signal.
>> >
>> > Not sure there's much I can do about it apart from hope the batteries
>> > run down quickly :-) but I'd be interested in anyone's comments.
>>
>> You are understandably assuming that the radio transmitter is causing the
>> interference, but that's unlikely given the likely frequencies involved.
>> It's much more likely to be the car itself, specifically its brush motor.
>
> That's quite possible too, I guess! Easy to test for - just use the
> transmitter with the car switched off.
>

It doesn't matter whether it is the car or the control, Openreach are fairly
toothless when it comes to any type of RF interference. If you did get a
case raised all they can do is investigate and report back to your ISP
(which isn't Openreach). As to what happens after that is up to your ISP or
possibly you.

For your sake I hope that the cars in question are cheap, shoddy grey
imports and get broken very quickly. It would be less painful and a whole
lot quicker than getting a REIN case raised, possibly proved or not (that
will depend upon whether the little tykes are out or not) reported back to
your ISP who do decide to pay OFCOM to investigate (they have the powers
now) who then alienate you from your neighbours. Personally a little talk
asking about their internet and if it's suddenly gone slow....you get my
drift.

On Thu, 11 Aug 2011 15:28:22 +0100, kraftee wrote:

> "Tony Mountifield" <(E-Mail Removed)> wrote in message
> news:j20h9l$2fh$(E-Mail Removed)...
>> In article <j20gth$9oo$(E-Mail Removed)>,
>> Graham. <(E-Mail Removed)> wrote:
>>>
>>> "Tony Mountifield" <(E-Mail Removed)> wrote in message
>>> news:j20e14$10g$(E-Mail Removed)...
>>> > Yesterday afternoon the kids in a family in our street were playing
>>> > with a radio controlled car. I noticed them out of the window of my
>>> > home office. The next thing I noticed was that my FTTC modem's DSL
>>> > light was flashing as it had lost sync. It regained sync when they
>>> > paused for a short while, only to lose it again when they continued
>>> > driving the car around. The one with the transmitter happened to be
>>> > standing right under the wire from the telegraph pole to our house,
>>> > and also directly above the underground conduit to the pole.
>>> >
>>> > Once they had finished and gone indoors, the line regained sync and
>>> > stayed up. I assume the (presumably) 49MHz signal was getting picked
>>> > up by my phone line (or perhaps the modem) and was to close to, or
>>> > overlapping with, the VDSL signal.
>>> >
>>> > Not sure there's much I can do about it apart from hope the
>>> > batteries run down quickly :-) but I'd be interested in anyone's
>>> > comments.
>>>
>>> You are understandably assuming that the radio transmitter is causing
>>> the interference, but that's unlikely given the likely frequencies
>>> involved. It's much more likely to be the car itself, specifically its
>>> brush motor.
>>
>> That's quite possible too, I guess! Easy to test for - just use the
>> transmitter with the car switched off.
>>
>>
> It doesn't matter whether it is the car or the control, Openreach are
> fairly toothless when it comes to any type of RF interference. If you
> did get a case raised all they can do is investigate and report back to
> your ISP (which isn't Openreach). As to what happens after that is up
> to your ISP or possibly you.
>
> For your sake I hope that the cars in question are cheap, shoddy grey
> imports and get broken very quickly. It would be less painful and a
> whole lot quicker than getting a REIN case raised, possibly proved or
> not (that will depend upon whether the little tykes are out or not)
> reported back to your ISP who do decide to pay OFCOM to investigate
> (they have the powers now) who then alienate you from your neighbours.
> Personally a little talk asking about their internet and if it's
> suddenly gone slow....you get my drift.

My experience of reporting interference to Ofcom is that they take so
long to get around to the case that the interference will have gone away.

I couldn't hear Radio 4 on 198kHz in the house because of huge wide-band
noise at repeatable times.
I reported it in the February, and by the time Ofcom got around to
looking at the case it was May. In the intervening months my neighbours
had some work done on their burglar alarm and the interference ceased.

"Tony Mountifield" <(E-Mail Removed)> wrote in message
news:j20e14$10g$(E-Mail Removed)...

> Once they had finished and gone indoors, the line regained sync and
> stayed up. I assume the (presumably) 49MHz signal was getting picked
> up by my phone line (or perhaps the modem) and was to close to, or
> overlapping with, the VDSL signal.
>

It may not be frequency-related, but a case of "blocking" where the "front
end" of the modem is overwhelmed by signal strength rather than signals at
any particular frequency and - effectively - switched off. This is a very
familiar problem - not just in the case of DSL - when a radio transmitter is
close to any type of broadband receiver's "aerial".

PA