The POTS ring frequency is 16-2/3 Hz (in UK), so it may be hard to detect.
Downstream ADSL traffic is upto 1104 Khz so you may be able to detect that with an AM radio. (just leave you-tube on auto-play or something like that.)
-- Jasen.
Except when it is shielded. I have an underground BT phone line (with VDSL internet) which uses steel wire armoured twisted pair cable. Two pairs I think. Such cable is very robust. It is also possible to attach a signal generator to the shield which might help with tracing.
John
Inject a signal in the AM radio band and use a small AM radio like you'd use a metal detector. Dunno if it'd be better to use the shield, fly the shield from ground or what.
-- Les Cargill
Isle of wight.
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Worth a try... with my metal detector with the phone ringing...
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Pity, I have the kit you need but the IOW is a long way to go.
You won't pick up anything from loop currents in the 'phone line, you need to inject longitudinal current in all the conductors in the same direction ('common mode'). Then connect a multi-turn coil to a sensitive amplifier and listen on headphones (a loudspeaker might create a strong enough field to give feedback). Frequencies around 1 to 2 Kc/s generally give the best results and pulsing them can help to make them more audible if there is a lot of noise.
The coil could be something like the mains primary of an old transformer with the laminations removed or the energising coil off an old loudspeaker. If you can fix it on the end of a broom handle and swing it to-and-fro like a pendulum, you will hear a sharp null in the signal when it is pointing directly at the cable.
Make sure your signal earth return path doesn't run anywhere near the cable you are trying to trace or you may find you are following the wrong one. Ideally you should hammer in an earth stake some distance in the opposite direction from the cable run and make your earth connection to that.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
I was asked to locate a break in buried wires to an electric security gate on a 1000+ acre nursery. I used a modulated signal in the AM Broadcast band, and a transistor radio to follow the signal. One of their Gardners had cut it with a shovel in three places. I found one, repaired it and the gate still didn't work. I found the other two breaks and repaired them, before it worked. The intercom part hadn't worked in years. I repaired that as well. I was tere to repair a C-band TV system. Before I l left that day I had also repaired a front end loader's damaged wiring harness. I always hated multiple jobs on one ticket!
-- Never piss off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-)
Just to follow this up, I've been making some measurements:
For the detector coil I used 2,000 turns of wire on a small plastic reel that had been used for solder, the winding space was 2" long, 2" outside diameter on a 1" dia core. I screened it against unwanted capacitive pickup with cooking foil, overlapped but insulated to avoid a shorted turn.
The amplifier was a NE5534 arranged for an input impedance of 47K, followed by a TL072; full gain was about 94 dbU into a pair of 30-ohm stereo headphones with the capsules wired in series mono and driven in 'bridge'. I have uploaded the circuit to:
A piece of wire lying on the surface of the lawn, carrying 1mA rms sinewave at 1.5 Kc/s was very easily detected at a distance of well over a metre. As this is magnetic induction, there will be very little attenuation from passing through the soil, so you could expect similar results with a buried cable.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
Call 811 first... oops that must be 118 Over There.
-- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
In the US, the locator companies typically inject 38KHz from a conductor to ground, and use a loop antenna and receiver to mark the route.
-- A host is a host from coast to snipped-for-privacy@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
ADSL is good for up to 8Mbps down and 448kbps up back to the exchange. ADSL2+ (current offering) will do 22M/1M on a good day but not for me.
Speed is intimately related to line attenuation and distance. I get about 5Mbps/1Mbps on a 5km 1960's copper line back to the exchange. Less if it is windy or the beck is in spate and the cable ducts flooded with water. Combination of overhead lines and buried so worst of both worlds.
Fibre to cabinet will get you closer to 80Mbps down 20Mbps up. That typically leaves only the last 500m on copper twisted pairs.
The graph at the bottom of this page shows the distribution of speeds and technologies in the UK at present (well in 2014).
FTTrN sank without trace some while ago. Some diurnal variation in SNR as continental radio broadcasts interfere a bit after sunset.
Cable TV is only available in cities. My brother in law gets 350M down/35M up on that with a cable TV feed.
-- Regards, Martin Brown
We have some friends in a small town with horrible internet, so one of their neighbors bought a microwave dish pair (amazingly cheap) and shoot across Tomales Bay to connect their neighborhood. At work we have a dish on the roof for internet and IP phones. It would have been a big deal to jackhammer the sidewalks to run fiber to our place.
Any way you can warm it up so you can use a thermal imaging camera?
-- Cheers Clive
UK ???
Never heard of Fox and Hound signal tracer ? Harbor Freight or other places .
The rural fast solution in the UK is a peer to peer (actually there are supernodes) microwave network. From the antenna size and available data rates I'd guess up in the 30GHz band somewhere. Particularly since there is a very strict line of sight requirement and no trees in the way.
It is popular with farmers since you get reliable 20M symmetric links or
30/10 and they are typically on unreliable
There are a few places where there are strictly enforced "no dig" zones typically around very high pressure gas pipelines. The one near me has a
50ft exclusion zone either side and a helicopter patrol once a week with a leak detector. Apparently if it did rupture it would be 180dB at 100m.There was a spectacular failure several decades ago, but most people have now forgotten about it. The expected mode of failure if it ruptured is exciting since the cold ethylene gas is heavier than air and will run down the hill to the sewage pumping station which may well ignite it.
However, most street digging is pretty hit and miss. Especially with the plastic gas pipes buried in the 1970's with no foil tape on to find them again. We were involved in an early ground penetrating radar to try and locate them. The official maps tend to be quite inaccurate so it is always wise to dig with the utmost caution in city streets.
-- Regards, Martin Brown
Many years ago a high pressure natural gas main was ruptured by digging close to the boundary of Guy's Hospital and Snowsfields in London. I think it took an hour or so for the gas company to find the appropriate shutoff valve. According to a colleague who was there at the time the noise was extremely loud even on the other side of a multi-storey building. Fortunately the gas did not ignite.
Later in the same area I saw an excavator that had fallen into a forgotten tunnel while it was digging on the site of a new building. That part of London is very cluttered underground and many records were lost and underground structures forgotten as a result of WW2 bombing damage.
John
Utilities in (under) the street -- or sidewalks -- are fairly well documented, here. But, once you leave the main feeders and move onto "private property", there are no real records that can be consulted.
And, the folks who come out (free of charge) from EACH of the utilities when you indicate that you'll be digging on your property are pretty cavalier about their work. They often "detect" the line (gas, electric, phone, water, etc.) in a few places and then INFER that it continues in a straight line "between the dots". (different color spray paint used to mark the ground for each utility's lines when you request this service).
And, they only guarantee their work to ~36 inches (i.e., if you dig more than
36 inches from their marks and hit a buried service, THEY are on the hook for the repair, else YOU!)Local gas company sent a guy out to mark our service. When the work crew came out a few days later (servicing the electric), I looked at the markings and told them that the gas company guy had made an error in marking where the gas lines ran.
Of course, they ignore "silly homeowner".
Then I told them that I had watched them excavate and install the gas main a few decades ago and could tell them EXACTLY where it was routed.
("Hmmm... maybe we'd better humor this guy?")
Amusing to see their reactions when they realize that if they'd ignored my warning and assumed the markings were correct, we'd have likely had a gas leak when they INTENTIONALLY tore into the space that the markings claimed was free of services!
Hell yes. And they will charge you even more if you dig up their services and break them.
Most spectacular one we had was a decade or more ago when a farmers hedge flailer took out an entire telecoms cabinet. Lots of coloured wire spaghetti and no phone service at all for a fortnight!
-- Regards, Martin Brown
Amazon will sell you a pair of dishes for well under $200, that apparently act like a long piece of CAT6. We get out internet from Monkey Brains, with a little dish on the roof. It's been great. We signed up for 50/50 speed and usually get about 400/400.
The line of sight is under half a mile, apparently to another of their dishes in some sort of distributed network. The initial proposal referenced a 174 dB link budget.
Even with my rotten eyesight, I can see about 30 or 40 various dishes from the roof of our office. It would be cool if all those beams glowed in the dark at night.
I assume that 6G or something will eventually replace the tangles that we use now.
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
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