Kitz Forum
Broadband Related => ADSL Issues => Topic started by: David Simpson on December 07, 2020, 09:16:32 PM
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As a newbie to this Forum, please bear with me as to questions raised. I wont boor you with the recent troubles I've encountered with BT & Openreach, as I'm sure many other subscribers in remote areas experience the same these days.
Since experiencing a horrendous bout of "Dropping-Out" about 3 years ago, I've made an effort to become acquainted with my POTS/ADSL 2.5 mile line from the exchange which I share with a couple of dozen other farming premises & cottages. Thanks to Kitz, and my pre-retirement employment as an electrical inspector & registered(MIET) electronics technician(more analogue than digital), I've managed to get my head around ADSL & the Audio/VLF/LF/MF frequencies up to 1.1MHz. My problem is asking the O/R Engineers the pertinent questions relating to the information they observe on their h/held analyser/tool. Some engineers are reluctant to show me the Bit Allocation Chart or S/N Chart. Many guys simply say that they don't know anything about the electronics involved. Many wont study the TDR info & jolly well set off walking the line. Mind you, just recently(more horrendous drop-outs) one brilliant guy spent 12 hours over 2 days doing just that & found over 50 faults. But he was the exception. Some guys say that they are not "Pole Climbing" trained, others say their not U/G JB trained.
So, please, is there a basic list of questions that I should ask ? Also, are Openreach legally obliged to reveal their test info, either visually or in writing ?
Regards, David
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Welcome to the Kitz forum. :)
. . . are Openreach legally obliged to reveal their test info, either visually or in writing ?
To the end-user, i.e. you or me, no.
To their customers, i.e. service providers, it depends upon the contract under which they provide the facility (to the service provider(s)).
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Hi David, and welcome to the forum :) - the ideal place to discuss bit allocations, SNR etc.
At the risk of invoking the evacuation of eggs by grandmothers - are you familiar with the tools provided by DSLstats (http://dslstats.me.uk/) and RouterStats (http://vwlowen.co.uk/internet/files.htm)?
One or other could help produce your own line stats, depending which router you have.
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Welcome to the forum David! ;D
If by chance you use a ZyXEL modem then we have some custom firmware developed by members johnson and later by siofjof that produces graphs including bitloading from a built-in secondary webserver in the modem itself. The user can then produce very informative stuff without any extra software even being required and it also has the benefit if you are using the device as a straight modem, not a modem-router, that the modem will support a PPP MTU of 1508 for a full IP MTU of 1500, not a reduced MTU of 1492. I use this on my VMG 1312-B10 modems and other models are supported too: see https://github.com/johnson442/custom-zyxel-firmware/releases (https://github.com/johnson442/custom-zyxel-firmware/releases). If you are using FTTC with vectoring take a look instead at siofjof’s build (we can dig out the url for that).
I find this custom software to be superb and it’s built from sources supplied by ZyXEL with johnson’s own huge contributions too. Even if you don’t use it, then excellent applications for a PC are available as already discussed. If you use no software at all, with a Broadcom chipset-based modem, or modem-router, you can telnet into the device and access its CLI to get stats including bitloading iirc.
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Hi David
I could spend hours chatting about this, but obviously won't do. It is quite difficult to answer a question that also brings individuals own personalities into the equation .... not just the engineer, but also the end user.
I use the term end-user, because officially that it what you are, David. Although I hate the term, the fact is our customer is the service provider and you in turn are theirs. So, our remit is to perform 'x' amount of agreed tests on-site, which then get automatically filtered back to the provider.
Our job is to prove to them that the metallic path facility they rent from us, passes an agreed 'cone of acceptance' test. Plus, to carry out an agreed 5 minute DSL test and an agreed audible noise test on the landline.
If all three pass (the first two tests being auto pass or fail, the last is dependant on the individuals hearing ability), then we are expected to pack up and leave and move onto the next customer.
Of course, this practice may benefit lets say 80-90% of customers, but there's always that grey area that will see repeat visits, I'm afraid. The reason the agreed COA tests are there, is to protect OR from the totally pedantic folk out there who chase a 0.5dB swing in SNR as a fault, wasting time and money for all concerned. Believe me, they exist .... some are on here ;) ;D. But genuine difficult/intermittent faults can also suffer as a result of this agreement.
However, the hierarchy are more than aware of these issues and have a triage team that should liaise with the provider after a certain amount of EU visits have occurred. Failing that, there's also the chairman's office team, as a last resort.
Regarding the engineers .... as with all walks of life and any mahoooosive company like OR, you get the full spectrum of people. I myself do not understand whatsoever, why you would not want to engage the EU and get them involved in what you are doing. I have only had ONE person tell me he had no interest in it and to 'Just fix it', in all my years faulting.
Most folk are eager to know what's going on and will quite happily listen to a laymans' chat about how DSL works and what we are looking for with out test equipment. More-so when you do have an intermittent fault, as you can show the EU that no amount of trying, the issue will not manifest itself whilst we are there on-site. It at least goes some way to show that we are trying to resolve or locate a problem.
But ... I've witnessed it with my own eyes, you do get the 'grunt' as we call them round here. Basically, rocks up, hardly any conversation in them, grunts a few words and buggers off. Seen them in hospitality roles throughout our travels and I often wonder WTF they have gone into a role they clearly have no patience or aptitude for ??
There's nowt as queer as folk, someone once said.
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Many thanks Guys for the encouraging replies. Having lived at the same address for 30 years, and being a BT customer all that time, plus having Internet access for about 20 years - - I guess we as a family had taken for granted our 2 wire rural O/H line. But about three years back annoying faults started. Back then, reporting faults involved call centers based in India, and I found that learning a smattering of Hindi produced wonderous results - quicker O/R visit bookings, getting passed on up to 2nd level knowledgeable staff & so on. So hey, me thinks that a similar approach is required with visiting O/R staff. More out of politeness than any sort of banging-on about my old electronics training & qualifications from an analogue yesteryear.
Thanks to Kitz, & info on the Wiki site I was able to gen up on basic ADSL principals involving a mixture of analogue & digital functions(6). Approx minus 48V DC on the B & A wires, 25Hz 75V AC Ringtone, Speech, Guard, Upload, Download. Then we get to the use of approx 250 virtual modems, QPSM, the micro-processing on the DSLAM board - - & so on - all wonderous but beyond my old analogue trained grey cells.
But now, with the latest spell of broadband faults, I guess I need to remove my digit & attempt to understand the 21st century technology. Mind you, our village exchange has gone fibre, but our remote postcode will not be eligeable till 2025. So me thinks that O/R is quietly giving up on the remaining spiders web of aging long O/H & U/G copper wiring. (Thankfully - no aluminium, I'm assured).
Hence joining this jolly interesting Forum & hopefully benefiting from much wiser & experienced guys.
Regards, David
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Mind you, our village exchange has gone fibre, but our remote postcode will not be eligeable till 2025.
Regards, David
Interesting .... when you say 'has gone fibre', do you mean full FTTP, or FTTC (Fibre to the Cab only) ?? Your line length from the Exchange to your premises is only 2.5km you mention, if it is FTTC and you have a Cab in the village, you may be able to benefit from higher speeds ??
Or, you could have been on a E/O line which means if it is FTTC, the Cab would be outside the telephone exchange (ie 2.5km away), which means the FTTC frequencies would struggle to reach you.
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The whole inter Village Network is Full 50Mb+, UG cabling. Villagers & close by residents all boast about their 50Mb speeds. Only those rural residents within a couple of hundred metres of the village to village UG fibre cabling get a fibre supply. The rest of us(some even over 3 miles away) are stuck with our ancient 2 wire POTS. When the scheme was announced over 4 years ago, I phoned the designated BT phone no & was told my postcode would get fibre in 2022. I inquired again back in August & was told 2025. One or two pessimistic O/R engineers quietly laughed at this.
So, I'm stuck with POTS/ADSL. If I'm lucky, I get an approx. asymmetry of 1:10, i.e. 0.37Mb Upload & 3.7Mb Download. In recent months the D/L speeds have been dropping to less than 1Mb & I've given up keeping a log of the numerous drop-outs. I received a brand new BT HomeHub6 about 5 weeks ago & an Eng. fitted a brand new Master Socket 5C. Ten days ago, another Eng. tells me the HH6 tends to suffer drop-outs at the end of such long lines. He reckoned the HH5 was more reliable.
So, an O/R Eng. comes into your house, listens to you whinging about multiple D/O's & slow speeds, then removes the M/S's front plate & wires in the tails from his "Tester"/ DMT TOOL/ "Hand Held"/ Analyser - - ? - - - all different descriptive names used by different engineers. What is the correct name, and am I right in assuming that there are two types currently in use ? Then - what is the sequence of testing/analysis he carries out ? ( Jesus - I wish I could get my hands on a decent one). (Hey - back in the 60's I used to service & repair RAF TDR's - over 2ft Sq. & weighed a CWT).
Regards, David
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There are only two types of hand-held tester (some updated versions of the two, as well) but they are simply the JDSU & EXFO testers.
The first test an engineer really would do is the simplest, listen to the dial tone for any signs of noise ... as if the low frequency audible signal is affected, the HF DSL signal will definitely be !!
Then, I personally would take the socket apart (as there may be high-resistance issues within the actual socket components), and attach the HHT direct to the incoming pair of wires. At this point, the engineer will perform the 'Pair Quality Test' which is an auto-scripted test looking at a plethora of different values, and very simply sums it up as a pass or a fail. Because of the 'cone of acceptance' a 'pass' may be very borderline and that is where knowledge is power.
Then, the 5-minute DSL close-out test will be performed, which sees the HHT hooked up as a modem and again it is an auto-scripted test that logs onto the ISP's RAS, and pings data back and forth looking to see if there is any data corruption present. Again, it is a pass or fail, but again .... experience and knowledge is power in interpreting a 'pass' result.
A simple method that can be deployed to try and 'force' a fault to occur, especially if it is a high-resistance issue, is to ring the landline number when the HHT is connected as a modem monitoring data flow. Another may be to bash the overhead wire with our measuring rods whilst data is flowing, especially if the wire goes through trees and rubs in poor weather ??. There's a few little tricks the seasoned engineer will have up his sleeve ...... but to get all pedantic (which is actually a bug bear of mine :-) ), our remit is to perform the tests as above. Nothing more, unless a faulty reading has been recorded on the HHT.
As an aside, I'm struggling to understand the lay-out of your villages connection ?? Is the telephone Exchange actually located in your village, or is it elsewhere ?? 2.5km is not a long line at all dependant on where the relevant equipment is located.
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The whole inter Village Network is Full 50Mb+
David, It might be helpful especially to Black Sheep to visit https://www.broadbandchecker.btwholesale.com/ (https://www.broadbandchecker.btwholesale.com/) and provide the resulting output however please be mindful to remove your actual telephone number which will appear at the top LHS. Attached is an example output from my own line - it provides the exchange, and local cabinet.
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...
As an aside, I'm struggling to understand the lay-out of your villages connection ?? Is the telephone Exchange actually located in your village, or is it elsewhere ?? 2.5km is not a long line at all dependant on where the relevant equipment is located.
Agree, when I was on ADSL, with a line length of approx 3km, I was getting about 7Mbps download and about 0.7Mbps upload. You should be getting a lot more than you are if the line is really only 2.5km.
:)
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You should be getting a lot more than you are if the line is really only 2.5km.
:)
The OP says 2.5 miles.
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Agree, when I was on ADSL, with a line length of approx 3km, I was getting about 7Mbps download and about 0.7Mbps upload. You should be getting a lot more than you are if the line is really only 2.5km.
:)
My line was about 2km (as the crow flies, so likely longer) but a certain amount of that is aluminium so it was 5.8Mbit only when I could push a 3dB SNRm, when MaxDSL came along that dropped to 3.2Mbit.
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The local exchange is plonked right in the middle of the village. It was completely refurbished back in the late 90's. All the old electro-mechanical racking was ripped out & replaced by U/T/D Digital equipment. Hell, I spent a half day there commissioning the new 3PH mains supply & testing all the metalwork bonding, wearing my electricity board's inspector hat. One long main st/high st, with cabling under-grounded & village poles removed back then. Obviously, the recent fibre project has changed all that. Those of us out in the hinterland of fields & lanes & single track roads, get our POTS/ADSL fed out of old green roadside cabinets out on the edge of the village. Then laterals of multi-cored U/G cables with changes to pole mounted JB's & O/H spans whenever a farm/croft/cottage appears. The very end of our U/G lateral is two spans away, then it changes to multi-core(7 pairs) for the remaining half mile, with overheads to us & three remaining subscribers further along. (Two of them have told BT to "Stuff-it" & changed to 4G Vodaphone), after a similar 3 years of a multitude of faults. Me - I'm hanging in there just now.
Regards, David
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The OP says 2.5 miles.
Oh yes, I picked up the 2.5km from Black Sheep's post - oops!
:)
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I'll try attaching a scan of my BT B.B Checker info , as per "Starman's recommendation.
Moderators - - am I allowed to attach a copy of your "Kitz Broadband Availability Checker" results page ? As it seems to have more detailed & advanced info.
Regards, David
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Moderators - - am I allowed to attach a copy of your "Kitz Broadband Availability Checker" results page ? As it seems to have more detailed & advanced info.
Yes, certainly. Go ahead. :)
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Thank you burakkucat. Will try another attachment. Earlier this afternoon, I did post another entry, several sentences long, and accompanied by coloured 2 photos. It seemed to be rejected 'cos the photos were too big. Tried to do a reduction, but then got put back to an empty message box. Tried again with shorter writing & a photo which was under the quoted limit - - poof ! Back to an empty message box.
Regards, David
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The local exchange is plonked right in the middle of the village.
That explains it then.
I wondered if you may have been fed via another larger town nearby (not knowing your location at the time), but I can see 'New Deer' has its Exchange right in the middle of it, next to the school ... and the estimator says you are fed through PCP2 (where the FTTC broadband product would begin its journey to you) ... which alas, is right outside the Exchange.
2.5 bananas ( ;) for the pedants ;D ) is a very long line indeed, with which to achieve an FTTC connection. It's not totally unheard of, but you would certainly need to have sections of higher poundage cable in your circuits feed, to alleviate the dB losses. The 7pr cable you mention though, I have never seen that above 0.5mm in size, which is an average poundage for most circuits .... unfortunately for those in outlying areas.
All in all ... not much you can do until FTTP arrives, other than chase your intermittent fault, mate. ???
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Thanks Black Sheep for the honest assessment. Much as I expected. The "Dropping Out" has stopped just now, but I'm still pessimistic.
When all the palaver started 3 years ago, I walked our nearest 3 pole spans with my 1950's ex marine portable AM DF Rx . Two spans back, where the U/G cable rose up to the O/H JB, I detected, whilst standing about a meter away - hellish noise at approx. 225KHz(Tone 52/ Bin 53 ?). I told O/R this, and an older(ex GPO Linesman/Technician) called by with a wee 1960's Tranny in his tool bag & confirmed my results. Seemingly, he'd been using it for years, as O/R don't issue their (men in vans) with any sort of stand-alone RFI tracing equipment. Me thinks I'll walk a lot further if the weather improves.
Me thinks that modern hengineers rely too much on their DMT TOOL, and DSLAM - MODEM adjustments(such as Bit Swapping, Active RFI cancellations, "Handshakes", & "Exchanges") - to sort out many faults. Rather than get out their Spikes, Belts, or Ladders & do some old - fashioned fault-finding in JB's. I recall back in 2017, over a three week period, about a dozen engineers came & went to us & our immediate neighbours. But only 3 said they were pole climbing certified or U/G chamber inspection certified. Christ, over 35 years ago, whilst working mainly as a commercial diver in the far north of Scotland, I did a six year stint as a Hydro-Board Emergency Linesman (240V S/PH. all the way up to 33KV). Consumers on remote mountainsides, or down remote valleys, would've shoved my spanner or screwdriver where the sun doesn't shine, if I had given some such excuse !
The D/F Rx I used is the middle one of the 3 in my collection, in the photo.
Regards, David
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I can't speak on behalf of your previous engineers, but it is a fact that there are both single skilled and multi-skilled engineers within OR.
I won't get into one about it, as it grinds on me the fact that both get paid the same (dependant on service - the new starters get incentive payments to acquire more skills). The problem we have is down to how e operate and that was as a result of Ofcom .... you can't talk directly to us, you have to go through your provider .... they in turn will run a remote line test and it will inevitably come back as 'line tests ok', due to the fact it's ok a lot of the time.
The providers systems then tells the fault receptionist which skill of engineer to send. So, it is very easy to have a chap turn up that doesn't climb, or doesn't do UG ??
When interaction was allowed between us, just the fact that you are in the sticks would usually see a multi-skilled operative despatched in the first instance.
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Right enough BS, as I mentioned at the start - A great multi-skilled chap did come out recently & spent 12 hrs over a two day period, and worked his socks off. But the three other just did their DMT Tooling spiel, and one of them did whack our pole to house O/H cable, but that was it. Normal POTS has never been an issue, and I ring the "Quiet Line" facility from time to time. So no 300Hz to 3KHz Audio complaints. We now have a local area BT "Home Tech" - just started. A great clued-up Radio/Telecoms professional. Served his time in marine radio/telecoms, and even knew some of the old hands I worked with as an engineer with Woodsons Radio over 30 years ago, after I stopped diving.
I've had a shufti at the Kitz "ADSL Technology & DMT" pages and studied the three examples of DMT Tool displays for :- "Bit Allocation & Power Cut Back", "Bit Allocation Table & Low SNR", "Bit Allocation & Long Lines". From the times I've managed to get a look at engineer's displays - I've never seen the first healthy display, but the 2nd & 3rd examples look familiar. So, a low bit allocation means slower speeds, I get that. I've never seen, or heard an eng. mention a display for the handful of bits allocated to the Guard VLF frequencies. If they suffer noise & SNR problems would that be a likely source of "Dropping Out". I.e. I'm phooked if the DSLAM & the Modem cant hold their virtual digital conversations ?
Regards, David
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> 0.37Mb Upload & 3.7Mb Download.
David I envy you, only 2.5 miles from the exchange ? I’m 4.5 miles from the exchange, best estimate I can make (7300m) although one Openreach document said cable length 8.1km which I find a bit strange. And I would love to have 3.7 Mbps downstream, although three of my lines are much better than yours at ~550 kbps sync rate.
Live sync rates:
#1: down 3122 kbps, up 528 kbps
#2: down 3001 kbps, up 579 kbps
#3: down 3096 kbps, up 396 kbps
#4: down 3206 kbps, up 573 kbps
My ZyXEL modem handles ultra-long lines very well, and my ISP is superb at dealing with faults.
If that speed isn’t enough for you, you could get a second line and bond the two together for double speed (I have four, for approx four times the speed in both directions; not so good in the upstream direction as downstream because of the weak line 3 upstream performance.)
That lot combined gives me 10.8 / 1.4 Mbps combined TCP payload on a good day, 10.2 / 1.15 Mbps on a bad day.
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> if the DSLAM & the Modem cant hold their virtual digital conversations ?
You need to increase the target SNRM as the modems are going too fast and need either/or more error correction information added, which extra data will slow them down, or else to go to a lower bit-loading makes the signal easier to interpret correctly.
My ISP’s controls let me adjust this. Some modems eg ZyXEL will let you adjust such things.
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Many thanks Weaver for the info on improvement equipment options. When things are OK, dropping-out wise, I'm quite happy with the approx. 1 : 10 asymmetry of 0.37 : 3.7 Mb. I'm not a multi-media teenage addict, nor am I into Facebook, Facetime, whatever. My wife sometimes uses Facetime on her tablet. And, back in Sept. when all this nonsense started, our daughter was visiting for a few days & went mental 'cos she couldn't work reliably on her O/U coursework. So I went mental & berated BT. Otherwise, my main usage is involvement with a forum site identical to this - UK VRR&R, and occasionally VMARS.
I've no fancy telecoms/computer equipment just - - O/R Master socket 5C on the window ledge, 18" away - the HomeHub6, about 2' away in the hallway - a BT Freestyle 710 with a wander handset. Out of the HH6 runs an ethernet cable about 8m long to my office/workshop in a lean-to out back. That terminates in a NETGEAR Fast Internet Switch FS608 v2, feeding an W10 HP Tower Unit & another BT F/S 710. Not much difference in BTW Speedtests either using my W10 HP laptop close to the HH6 or on the tower unit. Dropping - Out triggers wee warning boxes appearing on laptop or tower unit screens. Look at the HH - - Flashing Orange, the steady orange, than back to blue. At worst these sequences appear every 4 or 5 minutes for over an hour at a time. Back in Oct., one Eng. told me over 200 D/O's were recorded.
So, is there a modestly costed wee device I could plug into a spare port in my HH6 or the Netgear FS608 which would enable me to see Bit Charts & other DMT Tool displays on a computer . Or is there a simple downloadable APP which could do the same. Note the word "Simple" - I'm just an (old) old fashioned analogue guy, electronics - wise.
Getting back to the original subject question - I'm thinking of drawing up a wee questionnaire containing half a dozen pertinent questions. E.g. first question - is there -48V between the B & A lines ? - - and so on. Hey, someone told me that +ve floats at approx. earth potential, is that correct ? Obviously, its years since BT(GPO) incorporated an earth wire in the POTS supply to homes. But is it used for cable screening or Pole/UG JB's ?
Regards, David
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About interrogating your router. I don’t know much about the HomeHub. Broadcom-chipset routers and modems, such as ZyXEL, can display detailed stats and my ZyXEL modem can display such itself without even needing a special app, as it has a built-in secondary webserver which logs and records statistics and so a web browser can display detailed graphs over time etc and current statistics. With this kind of router you can also directly get current statistics using telnet. ZyXEL modems and routers are strongly recommended.
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is there -48V between the B & A lines ? - - and so on. Hey, someone told me that +ve floats at approx. earth potential, is that correct ?
The time has long since passed when the polarity was relevant and that leads me to the question: "How would you know which were the A & B wires of the pair?"
The answer is to earth the positive probe of your DVM (or analogue meter) and with the negative probe, test each wire. The wire showiing the greater potential difference is the B-wire, the wire with the lesser potential difference is the A-wire.
Go back to the electromechanical (Strowger) days and the potential difference between the wires of the pair could vary between 48 to 52 Volts, depending upon line length and its poundage. It was described a constant voltage feed (within limits).
With electronic switching, either System X or System Y, I have been told that the local loop is now a constant current feed (within limits).
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Thanks Weaver, I might well follow your advice & obtain a ZyXEL Modem if I experience more of these annoying episodes of dropping-out. Are they expensive, and is there a reliable supplier ?
Right enough, Burakkucat, I appreciate the irrelavence of line polarity these days. Actually 3 years back, several O/R guys kept changing the wall socket face plate filters. So, one day I stripped a discarded one bare & circuit traced & measured every resistor, capacitor & choke. And noted their relavent pin conn. numbers. Pin 5 (Red incoming wire) & Pin 2 (Green) on the rear term. strip actually exhibited 49V. And, as you've said might happen, my DMM revealed the green wire(pin 2) as the more -ve "B" wire. One or two experienced eng's have said in the past that 48/49V is what they expect to see.
Talking of voltages etc., Guard/UL/DL tone-wise are we talking uV & uA, or perhaps a mV or two. I'm guessing that some of the DIL chips & micro-circuitry in HomeHubs & Modems have an amplification roll ?
Also,(apologies for all these questions, I'm just trying to get my grey cells around 21st century technology), which important(Guard?) frequencies are susseptable to harmonic interference/distortion or other problems ? I've nothing that can detect sub-25KHz RFI-wise. I've a wee h/held GDO/RF detector, but that goes no lower than 70KHz.
Hey, as recompence for all my heffing questions, & my gratitude for helpful replies, if any of you guys have a leaning towards vintage radio/electronics - please get in touch, particularly in regard to valves & valve testing. And, a wealth of more experienced/qualified expertise can be elicited on the UK VRR&R Forum(www.vintage-radio.net). Like youse folk - very helpful guys.
Regards, David
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Regarding ZyXEL routers the VMG8924 and the VMG3925 are ones I can vouch for as I have used both and currently have my 3925 in use not been booted for 241 days and the DSL link has been up 64+ days. Second user items usually available on eBay for between £20-£40. Both have 5ghz wifi, although I have mesh wifi system as it is problematic in my house!
Stuart
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Agree with Broadstairs. I use ZyXEL VMG1312-B10A devices but mine are configured to be in straight modem-only mode, ie they are not routers, although they can be easily. But Broadstairs’ recommended models have better wireless LAN capability and are slightly easier to get hold of. Mine have been extremely reliable never crashed or hung. My units are set up to be modems because I have four lines and so four modems and a router to handle them all. Burakkucat and Kitz herself both use ZyXEL routers as do others of our tribe.
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I see there is another thread about "HAM Band Notch". But are there any such "Band Notches"(Filtering or Blocking circuitry ?) for sub 25KHz ADSL tones or frequencies. I seem to recall that some VLF Nav Aids are still in use, but don't know their frequencies.
I have a HAM licence, but haven't been on-air for quite some time. Just 80m(approx 3.6MHZ), but that's way above ADSL's 1.104 MHz. My rig is a restored 1950's AM HF ex Marine Band Tx & a lovely old Eddystone Rx, but nowadays the 80m Band, AM-wise, is full of noise, eastern european chatter, & SSB yappers. In my contact with local amateur radio chums over the years, I've not heard of any Ham related ADSL matters. There is a massive military VLF TX Station about 12 miles away, but I haven't a clue of frequencies involved. I doubt if local normal O/R mannies in vans would ken onything aboot sich matters.
Regards, David
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Talking of voltages etc., Guard/UL/DL tone-wise are we talking uV & uA, or perhaps a mV or two. I'm guessing that some of the DIL chips & micro-circuitry in HomeHubs & Modems have an amplification roll ?
Previously, above, I was just mentioning the telephony situation with regards to the incoming pair. As for the internals of a modem (or modem/router), I have never closely looked or analysed . . . All I can say, for certain, is that there is a high-pass filter before the analogue front-end. The high-pass filter is just a pair of appropriately rated capacitors, one in each leg of the pair.
When I am checking for any potential RF ingress into a xDSL circuit, I will use my Icom IC-R5 tuned to 300 kHz.
As for any other relevant frequencies, I'll have to let other members answer the question.
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I've just had a thought. Have you seen Stephen Wilson's (G3VMW) "Staying Connected to Your Broadband ‐ An Improved ADSL Filter (http://qso365.co.uk/wp-content/uploads/2012/02/ADSL-filter.pdf)" article (a PDF file)?
It was originally written back when ADSL (ITU-T Recommendation G.992.1) was the then current technology.
Other sites that I use for reference, when considering xDSL problems, are --
http://www.mediumwaveradio.com/
https://www.short-wave.info/
http://www.frequencyfinder.org.uk/
https://tx.mb21.co.uk/
[Edited to correct the paw slippage, as noticed by Weaver.]
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O/R mannies in vans
It's a long time since I heard reference to "mannies", thought I was back in the north east again!
Spent a lot of my working life in or mostly transiting through Aberdeen so was practically fluent in Doric.
Perhaps you should explain "mannie" to the uninitiated, might even elaborate further on "lune, quine and wifie".
I remember the standard greeting to a young lad was "fit like lune".
Also a long lapsed radio ham, internet growth just made world wide communication too easy.
Sorry to digress from topic, couldn't resist!
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Should "G.993.1" read "G.992.1" ?
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Should "G.993.1" read "G.992.1" ?
:-[ Yes, of course. The paw slippage has now been corrected. Thank you.
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Many thanks to Burakkucat for those links.
Re "Tiffy" - hopefully the Mods wont mind a bit of explanation on local dialects in the North of Scotland. Like Weaver in Skye, no doubt, in the NW I picked up a smattering of Gaelic. Then since arriving at RAF Lossiemouth in '73, I've picked up a fair bit of the "Doric". More so since moving to Aberdeenshire in '84, after leaving the NW.
But hey, the word "Tiffy" has an extra meaning for me, as 8Sqdn at Lossie was half Navy/half RAF. A Tiffy was an Artificer trained technician - a bit above the normal ranking scales, so many gained PO or CPO status quicker. My ventures into Ham radio were just a side-line, as I could obviously no longer Tx half-way around the globe on military HF equipment. Nor, since ceasing working on marine equipment, could I legally yap to fishing boats, coastal stations or oil rigs. Anyway, nowadays its vintage radio, test equipment, etc. which I'm involved with. And recent ventures into understanding B/B & ADSL have been an eye opener & grey cell enhancer. Plus raising my BP(must be careful with that) over BT & O/R inadequacies in our rural area. 'Not singing from the same hymn sheet' is a common term up here in the NE.
Regards, David
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Hi David,
Yes indeed, well spotted, Tiffy refers to my old trade, instrument technician in the petrochemical industry.
The origin I believe goes back to the late 1950's, 1960's when ICI in Teeside first decided that there was a requirement for a "third" trade beyond fitters and electricians specifically to work on the new fangled control systems, a lot of which were pneumatic in those days before industrial electronics really took off.
Being a new trade at the time, ICI decided to adopt the forces terminology of "Instrument Artificer" as the closest anology to the job requirements, being a bit of a mouthful, this was quickly shortened to Tiffy and has remained the case ever since with the official job title now being Instrument Technician.
Regarding HF radio comm's, this had been officially dropped in the larger North Sea installations before I left 5 years ago, had been used as a backup for the LOS/Tropo first line comm's, satellite changed all that of course.
Have also found the DSL technology facinating, have become quite addicted to stat's monitoring and learned an awful lot from the patrons of this site.
However, things are changing very quickly now with the big push to FTTP, nothing to monitor then, either works or doesn't work, no in betweens!
Apologies again for drifting off topic.
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Hi David,
Yes indeed, well spotted, Tiffy refers to my old trade, instrument technician in the petrochemical industry.
The origin I believe goes back to the late 1950's, 1960's when ICI in Teeside first decided that there was a requirement for a "third" trade beyond fitters and electricians specifically to work on the new fangled control systems, a lot of which were pneumatic in those days before industrial electronics really took off.
Drifting further off topic so apologies in advance.....
In the late seventies and all the way through the eighties I picked up bagged fertilizer from ICI at Billingham being a lorry driver for 35 years of my life. :blush:
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To get back onto subject, apart from the digital modulation twchniques, and the multitude of micro-processors in Modems & DSLAM's, (which my aged analogue brain struggles with), the basic use of audio frequencies & VLF/LF radio frequencies isn't rocket science. RF-wise, two wire(un-screened) usage was always going to be a problem, as opposed to us other lot mainly using Z rated co-ax, for BT & other ISP's. BT & O/R do their best to attain a high S/N Ratio, but externally - anything sparking or producing anything near a sq.wave is a bummer, RFI-wise(theoretically - infinite spectrum). One of the questions I always ask the O/R guys is ' have you seen anything suspicious between us & the exchange'. But their remit just seems limited to using the DMT Tool. In my early HEB Linesman training, and later Electrical Inspector training, we were encouraged to physically observe as much as we could network & installation - wise, as opposed to just using test equipment. I guess my current frustrations with BT & O/R stem from this.
As for record keeping - Jesus, military-wise every action/repair/inspection had to be signed up, then oversigned by an NCO. In the recent D/O fiasco, the poor chap who carried out 12 hrs of work, said that he'd lost at least two hrs due to the wire pair changing done 3 years ago - not being written up in the exchange's log ! In the military, and I expect in the old GPO days, this would've been a serious disiplinary matter.
Regards, David
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https://tx.mb21.co.uk/
[Edited to correct the paw slippage, as noticed by Weaver.]
This link is interesting as I was able to review the history of Winter Hill. I was fortunate to have been to the top in the lift ( long taken out of service) on a visit by our local radio club.
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This link is interesting as I was able to review the history of Winter Hill. I was fortunate to have been to the top in the lift ( long taken out of service) on a visit by our local radio club.
Worked at Winter Hill repeater station many times over the years. Treacherous drive up in winter time, but the views are spectacular on a clear summers day ... you can see over to the river Mersey and also down to Jodrell Bank.
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Agreed a great view but access is restricted now or rather has been for some years. Never ventured in the winter, but I can imagine!
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Never made it to Winter Hill with our school's cycling club(in Bootle), but made it to Parbold Hill, & Jodrell Bank. DS
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Can you hear any noise when you Dial 17070 op2 (free call) on a land line phone.
Also does your very long line go near any Sheep electric fence's in the fields it passes ?.
My line is nearly 3mile long in old money I am on ADSL2 (Soon to get FTTP :) and get about 3.5 to 4Mbps on a good day with the wind in the right direction.
Can you post your Modem/Router Stats.
PM sent
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Aye, Tickmike, I regularly dial up the BT"quiet-line" number, & everything is tickerty-boo. ADSL problems is my beef.
3 years back, myself with my DF Rx & an experienced older OR guy with his LW/MW Tranny walked up the road a bit & easily detected the RFI from a neighbour's menarge & paddock. Also, for years it can be heard on my big static Eddystone 730/4 Rx. Thankfully they are one of the neighbours, further along, who have recently told BT to "stuff-it" & changed completely to Vodaphone 4G. Over the 2.5 miles back to the exchange there will no doubt be sheep & cattle electric fencing in odd places. I also know of at least two grain drying sheds with either 480V split-phase or 415V 3 phase machinery. As I said in an earlier post a few days ago, I plan to "walk the line" back to the edge of the village, weather permitting sometime, & see just what I can detect RFI-wise.
Mind you, a big article in today's local paper - - BT just awarded a huge £385 million contract to quickly roll out FTTP to remote areas, with Scottish west coast islands & the Highlands getting priority ! So Weaver's problems will soon be over, & he'll be able to flog off surplus ADSL enhancing stuff to us lesser privilaged mainland teuchtars.
Re my BT & domestic computer equipment - all info on page 2 a few posts back.
Regards, David
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Re my BT & domestic computer equipment - all info on page 2 a few posts back.
No I mean like this below, this is the info off my Modem, It uses DSLstats by Eric (roseway) :)
http://dslstats.me.uk/index.html
xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 940 Kbps, Downstream rate = 5512 Kbps
Bearer: 0, Upstream rate = 885 Kbps, Downstream rate = 4022 Kbps
Link Power State: L0
Mode: ADSL2 Annex A
TPS-TC: ATM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.5 7.0
Attn(dB): 52.5 31.3
Pwr(dBm): 0.0 12.7
ADSL2 framing
Bearer 0
MSGc: 59 10
B: 125 40
M: 1 4
T: 1 3
R: 10 8
S: 0.9945 5.8803
L: 1094 234
D: 32 4
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Hey tickmike, as I've said in a few posts - I'm just an old analogue guy. Computer software & Modem software, etc. are way out of my spectrum of electronics/radio/telecoms knowledge. In the 21st century, such equipment is just a tool to enable me to generally communicate with family & friends, plus carrying out research, or passing on info regarding vintage radio/electronics pursuits. Right enough, I'm endeavouring to understand telecoms-speak regarding my stumbling current venture into ADSL & it's problems. About 55 years ago, telecoms-wise I did do some training on RAF teleprinter servicing & learnt the Murray Code. Also did some basic servicing on PBX equipment. we're talking 1965 not 2020.
Want in-depth knowledge on testing & Gm graphing an 807 Beam Tetrode ? - - - I'm your man. Need some spares for a 1930 TRF Rx ? - - I'll see what I've got on the shelf. Want info on wee micro-chips, virtual modems, and QPSM ? - - - I'm just a thicko compared to you chaps on this forum.
Regards, David
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I noted the reference to an Eddystone 730. I had one of those beautiful kit. I assume you can still source the valves to keep it running.
I made loads of stuff including linear amps for 430mhz. Using the forced air 4cx150 triodes. Great fun and lots of 2.5k power supplies ! Tony
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Hey Tony, get your arris also onto the VRR&R Forum. Heaps of guys would love to hear about your great linear amp projects. Re the Eddystone 730/4 Rx - - if you've got a suspect valve or two, let me know & I'll see what I've got. Also there is a dedicated "Eddystone" site, which can source many a spare replacement item.
Apologies to Mod's for drifting O/T. Mind you, thumping big Triodes are still in use today for "line of site" transmission of VHF/UHF Telecoms. Likewise, thumping big Beam Tetrodes & Pentodes for LF & HF terrestial work. Then you've got Satcoms & Troppo & God knows what. 50W out of 3 parallel 807's is all I've got out of my restored 1950's Coastal Radio Nimbus AM HF Tx.
Regards, David
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I thought I'd heard the last of 807's :P
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I thought I'd heard the last of 807's
This house I'm building I put some 807's, ECC 83's etc. and others along with un-wanted electrical stuff in voids in the house ;D some one is going to have a shock if ever these voids are opened up :)