Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: Semmy on May 09, 2014, 12:14:42 AM
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Having finally gotten around to unlocking and flashing a HG612 I can now see my full stats.
On checking for issues which could be affecting my connection I found the following:-
A gap in bit loading on three frequencies 909, 1089 and 1215kHz
After a bit of a search I have identified these as BBC Radio 5 Live, Talk Sport and Absolute Radio.
The nearest source for these signals is Moorside Edge transmitter (approx 15 miles away) transmitting at 200kW!
Do I have any options to reduce or remove this interference as it leaves three significant gaps in my capacity (and indeed bleeds into the surrounding tones too)
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Hello Semmy and welcome to the Kitz forum.
Congratulations for your successful research in finding the origin to those gaps in your bit loading. :)
Unfortunately (for you) those three broadcasters are licensed to make use of those frequencies whereas we, users of xDSL signals carried on a metallic pathway, have no "rights" / "say" / "privilege" to any of the frequencies that we attempt to use. :no:
The only way that such RFI can be minimised is to ensure that circuit has good AC balance, there are no HR or semi-conducting joints anywhere along its length (which could allow cross-modulation & perturb the differential mode of the CO to CPE circuit), a Mark 2 SSFP is fitted at the NTE5/A and the length of the circuit from the SSFP to the modem/router is kept as short as possible.
Depending upon whether you would be willing to accept the insertion loss, the fitting of a BT80-RF3, just before the NTE5/A, may also help to minimise those signals' ingress.
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I hope you don't mind me jumping into this thread as this seems very similar to my RFI issues over the last 11 months and I did the MKII job but to no avail, how would one go about fitting the BT80-RF3 (DIY)
edit spelling mistake BC would pull me up on this :-[
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Semmy, as burakkucat says the RF3 has loss, but it is S/( REIN + RFI) which matters, not just S.
IF you are in a suburban area with a lowsish background of REIN it still can pull extra tones out of the background, as well as seeing off RFI and improve overall. As a BC station is 10 kHz wide, a strong one can see off 3 4kHz tones.
In my situation with weak RFI (underground phone lines) the result is marginally worse.
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To be fair I am on a moderately long line at ~700m from the cabinet however the cable remains underground for the majority of the journey only appearing above ground at the pole opposite my house, crossing the road then descending into the house on the ground floor.
Am I correct in thinking that this would be the most likely point on the line for the RFI to enter as the underground cable would be well shielded?
Is it possible to "obtain" shielded overhead cable as I suspect it would be better to prevent the RFI from entering rather than filter it out after the fact?
I have taken most other possible precautions:-
50cm twisted pair cable from the SSFP to the modem
1m shielded cat6 cables to the router
Ferrites on the switch mode power supplies DC leads (though I am pondering using linear PSU's - a cheap option CPC - Farnell do them at £6ish)
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Am I correct in thinking that this would be the most likely point on the line for the RFI to enter as the underground cable would be well shielded?
Yes ! (unless you live on dry sand !)
Is it possible to "obtain" shielded overhead cable as I suspect it would be better to prevent the RFI from entering rather than filter it out after the fact?
Yes better But AFAIK this is a matter for BT and so may not be practice, burakkucat may know better.
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Just had a quick squint at the RF3 and it appears to have a common mode choke as the only "component", so I guess the only hassle would be the added impedance of the choke on the line which would attenuate the signal a little.
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Ferrites on the switch mode power supplies DC leads (though I am pondering using linear PSU's - a cheap option CPC - Farnell do them at £6ish)
Hi,
Having also been here myself (though with intermittent interference, rather than a broadcast station), I tried running the modem/router from a 12 volt battery to entirely eliminate mains-borne interference.
For me, it made no difference. But before going to the trouble/expense of building or buying a fancy PSU, if you've got a 12 volt battery from a rechargeable drill, or a spare 12 volt car battery, consider charging that up fully then running your equipment from it.
As I said, for me it made no perceivable difference, but might be worth a try if you've already got something suitable.
Ian
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The only way that such RFI can be minimised is to ensure that circuit has good AC balance, there are no HR or semi-conducting joints anywhere along its length (which could allow cross-modulation & perturb the differential mode of the CO to CPE circuit), a Mark 2 SSFP is fitted at the NTE5/A and the length of the circuit from the SSFP to the modem/router is kept as short as possible.
Depending upon whether you would be willing to accept the insertion loss, the fitting of a BT80-RF3, just before the NTE5/A, may also help to minimise those signals' ingress.
Surely the main point of the Mk 2 SSFP is that it obviates the use of an RF3 as it contains the same inductors ?
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Surely the main point of the Mk 2 SSFP is that it obviates the use of an RF3 as it contains the same inductors ?
Ah but not quite.
As Black Sheep has mentioned, previously, the wizards of Grimbledon Down1 have determined that the Mk 2 is still somewhat deficient in its action (I fully expect a Mk 3 to eventually appear) and the current instructions, issued to all Openreach engineering staff, specifies that a SSFP plus a BT80-RF3 should be fitted when attempting to minimise the RFI on an xDSL circuit.
[1] A.k.a. Martlesham Heath (http://en.wikipedia.org/wiki/Martlesham_Heath)
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Just had a quick squint at the RF3 and it appears to have a common mode choke as the only "component", so I guess the only hassle would be the added impedance of the choke on the line which would attenuate the signal a little.
Yes, that is correct. JGO has provided a useful description of how it operates in an earlier forum thread (http://forum.kitz.co.uk/index.php?topic=13473.msg253918#msg253918).
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I hope you don't mind me jumping into this thread as this seems very similar to my RFI issues over the last 11 months and I did the MKII job but to no avail, how would one go about fitting the BT80-RF3 (DIY)
The BT80-RF3 (block terminal 80, RF3) is identical in size and shape to the standard BT80 (block terminal 80). So if there is a pre-existing BT80 in the circuit, joining the incoming service feed cable to the internal CW1308 cable (for example), then a direct one for one swap would be the simplest way. Or you could fit a BT80-RF3 adjacent to the NTE5/A (Senior Management permitting :-X ), disconnect the cable from the NTE5/A and connect it to the screw terminals of the BT80-RF3. Then use a short length of CW1308 cable to connect from the NTE5/A to the IDCs of the BT80-RF3.
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Just for info on the aesthetics, seeing as all techy advice is more than covered as usual ;)
The 'Gubbings' within the RF3 can be removed and will actually fit inside the NTE5 (Master Socket). Ergo, out of sound and out of mind should 'Da boss' object to unsightly additions ?? :)
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Just for info on the aesthetics, seeing as all techy advice is more than covered as usual ;)
The 'Gubbings' within the RF3 can be removed and will actually fit inside the NTE5 (Master Socket). Ergo, out of sound and out of mind should 'Da boss' object to unsightly additions ?? :)
What excellent advice! :) That will certainly minimise the chance of the War Department taking offensive action. ;)
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Thank you, kind sir. ;D
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The BT80-RF3 (block terminal 80, RF3) is identical in size and shape to the standard BT80 (block terminal 80). So if there is a pre-existing BT80 in the circuit, joining the incoming service feed cable
Unfortunately I dont have a BT80 installed in the front porch as the PVC door smashed the casing 20 odd years ago and did a diy job using a round block terminal, so if I am right I just need to purchase a BT80-RF3 (block terminal) and remove this 20 year old DIY job and install and connect the incoming terminal A & B to the block and reconnect terminals for the NTE5 feed.
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Correct ……… or as per my previous post. :)
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So a lot of us are suffering from this issue to differing degrees, and it doesn't seem like much can be done to filter it from the signal. Would it not be more effective to try and find a way of preventing it getting into the signal/line in the first place?
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So a lot of us are suffering from this issue to differing degrees, and it doesn't seem like much can be done to filter it from the signal. Would it not be more effective to try and find a way of preventing it getting into the signal/line in the first place?
As that could be read as a rhetorical question, I shall just pose my own, as an addendum . . .
Would it be even more effective not to use a technology that makes use of radio frequencies which are licensed for other purposes? :D
[b*cat now has a mental image of Walter preparing to post a missive on the benefits of deploying symmetric FTTP . . . ;) ]
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Correct ……… or as per my previous post. :)
:) it's purchased and on it way to RFI land its a GENUINE BT 80B RF3 JUNCTION BOX WITH RFI PROTECTION FOR USE WITH ADSL CABLING no mention of VDSL :o
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So a lot of us are suffering from this issue to differing degrees, and it doesn't seem like much can be done to filter it from the signal. Would it not be more effective to try and find a way of preventing it getting into the signal/line in the first place?
Discussed to death many, many, many times .... LL. :)
It's all down to the bottom line of the accountants sheet. We're pumping frequencies down cables that were lain decades ago, that simply were not designed to carry them.
Of course, FTTP is the ultimate answer, but it is NOT going to happen overnight.
I can't be bothered trying to reference it, but I read some years ago about some Oz scientist who managed to pump some astounding DSL speeds over bog-standard twisted copper pairs. He had basically eliminated all noise, but in laboratory conditions.
The problem we have as human beings is the fact we are needy and greedy. Just over a decade ago we could only expect 0.5Meg speeds, and today we can get 80Meg ....... but we still feel the need to get more. nothing wrong with that, it just won't happen right here ... right now like some would like it to be.
It still amazes me even now, when I attend a task and the EU has months of historical DSL stats and has collated information to say he should have 0.3 Meg more DS speed and his 'Ping' has risen by 2mS. I often think to myself, if you'd spent more time cleaning the disgusting pig-sty of a house, or got off your arse and got a job, then you might not be as obsessed with this ridiculous request you have got me to site for !!!
The difference wouldn't make any difference, when they are browsing .... if you follow my drift ?? :)
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Correct ……… or as per my previous post. :)
:) it's purchased and on it way to RFI land its a GENUINE BT 80B RF3 JUNCTION BOX WITH RFI PROTECTION FOR USE WITH ADSL CABLING no mention of VDSL :o
JGO and B*Cat are the gentlemen you require for the low-down on the tech spec, NS. All I know is it is best used in conjunction with the SSFP to eliminate as much 'Noise' as possible.
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JGO and B*Cat are the gentlemen you require for the low-down on the tech spec, NS. All I know is it is best used in conjunction with the SSFP to eliminate as much 'Noise' as possible.
No worrys Black Sheep have the MKII SSFP at the ready, so once BT80b RF3 arrives it a power down on the HG612 and power off the router and remove adsl cable from HG612.
Install BT80 and connect wires then replace MKI SSFP with MKII SSFP at the NTE5 master socket reboot modem and reboot HG612 and connect ADSL cable to HG612 jobs done ;D
that would cost you £150 from BT but the DIY only costs £3.99 for the part ;)
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Just for giggles here are a couple of graphs of my connection ???
It is really easy to identify the three radio frequecies in tone 200 - 325.
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:) it's purchased and on it way to RFI land its a GENUINE BT 80B RF3 JUNCTION BOX WITH RFI PROTECTION FOR USE WITH ADSL CABLING no mention of VDSL :o
Assuming that it is one of the genuine articles, as supplied to Openreach, then there will be no problem. Such devices are regularly fitted (by sheep with fleeces of various hues) to all types of xDSL circuits every day.
I'm sure that the description you have quoted, above, is just a marketing advertisement. Looking at that well-known, on-line auction site I see this item (http://www.ebay.co.uk/itm/GENUINE-BT-80B-RF3-JUNCTION-BOX-WITH-RFI-PROTECTION-FOR-USE-WITH-ADSL-CABLING-/261421630409). If that is what you have ordered, then it will be fine. :)
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It is really easy to identify the three radio frequecies in tone 200 - 325.
Agreed. The are rather prominent. :(
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I have to admit that one of the guys at work who considers himself a bit of a wit suggested wrapping the overhead line in tin-foil......
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I have to admit that one of the guys at work who considers himself a bit of a wit suggested wrapping the overhead line in tin-foil......
funny, but would probably work.
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Received the BT80B RF3 to-day and it's very small no bigger than a match box this is going to require a large magnifying glass and two large Beers to steady the hands.
Not sure to mount this vertically or horizontally, if Horiz then A & B wires can come in from right and on to the screw connectors and NTE5 wires can enter from the left to IDC connectors.
Have any of you any tips ;D
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Horizontal has been scientifically proved to minimise CRC errors. ;)
As you say, it is quite small - just be sure not to trap any wires when screwing the lid on.
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Horizontal has been scientifically proved to minimise CRC errors. ;)
As you say, it is quite small - just be sure not to trap any wires when screwing the lid on.
Thanks 4Candles for the :D it's just the BT logo on the case will be pointing towards the ground when in Horiz mode ::)
Cheers
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I know this a odd question these RF2 and RF3 filters are designed to filter RFI at the NTE5 and before the NTE5, so lets say the RFI is being picked up from the Data Socket cable (FTTC extension) then neither of those filters will make any difference in that case.
So do you think it would be a good idea to have the RF3 filter placed just before the Data Extension Socket for users with this kind of setup ?
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O.K. So the RF3 is now fitted.
Here is a before and after ???
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The RF filters were originaly intended to filter out unwanted electrical inteference which is audible with normal voice telephony. Radio stations, taxi radios, offshore marine transmissions along with whoops,crackles and whistles generated by a local source causing an annoyance when trying to tell the person at the other end of the line, No you're not interested in double glazing. hence they are fitted before the NTE.
Otherwise in the case of DSl, the router is the only appliance connected (normal voice aside) so it could make sense it fiting an RF just before the routers socket.
And as Blacksheep stated, the innards of an RF3 can fit in the back box of an NTE5 (as long as its not a NTE5 elite, you can barely fit anything behind one of those, including a drop wire)
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O.K. So the RF3 is now fitted.
Here is a before and after ???
Oh dear it looks worse :( at tone 1710
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To be honest I suspect there may be other issues at hand now.
On initial install my line was synching at 45/11 (max attainable).
Over the next couple of weeks that dropped as more folk joined the cabinet ending up at 38/9.
Unfortunately on Friday the synch dropped and I am now at 30/7,
We are subject to Kelly Comms guys here for install and wonder if they have "broken" something whilst adding another customer.
Any suggestions?
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To be honest I suspect there may be other issues at hand now.
On initial install my line was synching at 45/11 (max attainable).
Over the next couple of weeks that dropped as more folk joined the cabinet ending up at 38/9.
Unfortunately on Friday the synch dropped and I am now at 30/7,
We are subject to Kelly Comms guys here for install and wonder if they have "broken" something whilst adding another customer.
Any suggestions?
Well that's why you need to have a steady line before installing these filters to see if it does make any difference, now you don't know if it was the installation of the RF3 or a line fault that is causing this issue.
Sorry Semmy if you installed the RF3 as a fix for a line fault then you wasted time and money :o
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It's O.K. I was trying the RF3 filter to try and minimise the RF interference I had identified earlier in the post (the triple spike between tone 200 - 300).
Unfortunately the RF3 has had no impact upon this, though I am giving it a little time to settle before making a specific decision.
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It's O.K. I was trying the RF3 filter to try and minimise the RF interference I had identified earlier in the post (the triple spike between tone 200 - 300).
Unfortunately the RF3 has had no impact upon this, though I am giving it a little time to settle before making a specific decision.
No worrys semmy it looks like I have also wasted £3.99 on RF3 it's not installed and may no be after seeing your graphs :(
and TBH I think BT OpenReach install these RFI filters as a placebo effect on customers making them think their RFI has gone >:( >:( >:(
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I suspect it may work as the principal is correct but only for a limited value.
When faced with the rather large scale interference I have on those tones I think almost any filtering solution would struggle.
I may have to resort to wrapping my drop wire in silver foil after all :P
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At my previous property there was an underground feed to the house, then a long route through the loft to the NTE5A.
As the line was moderately impacted from the BBC transmitting site (Burghead - LW & MW) about 21 miles away, I tried wrapping the loft cable with Bacofoil *, and even earthed it.
Effect? Zero. :no:
* Other cooking foils are available.
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At my previous property there was an underground feed to the house, then a long route through the loft to the NTE5A.
As the line was moderately impacted from the BBC transmitting site (Burghead - LW & MW) about 21 miles away, I tried wrapping the loft cable with Bacofoil *, and even earthed it.
Effect? Zero. :no:
* Other cooking foils are available.
there is a cure for RFI, it comes in a pack (plastic explosives,and manual detonater the wireless detonater is extra) place 1lb at each corner of Mast and enjoy, for safety reasons make sure your 700 yards away from any falling debri.
Its only a Joke don't try this at home ;)
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As the rfi's are a passive device, they cannot dissern between what is unwanted noise and the dsl signal they are supposed to let pass. There in lies the problem. The RF2 was around before DSl so it filters out a lot of the DSL signal. If i remember when I tried testing one in an exchange it added about 40 something db loss to the signal. or will allow sync for up to 2.7km of line on 0.5mm copper.
The RF3 tried to cut out a lot of noise but allows the DSL frequencies through. (the rf2 filter is similar or identical to the one on the bell wire on the newer filtered face plates so filtering out the bell wire noise greatly just as 2 of them, one on each leg does in an RF2)
If the noise thats causing you a problem is a different harmonic to the dsl frequencies then the rf3 will help. If its the same harmonic then there's no difference. From your results your situation is the latter
Incidentaly with harmonics, thats why for REIN a radio is tuned to 612 KHz dispite the key frequency being half that, just a radio that works in the same frequency is difficult to obtain.
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Just a quick comment.
On the occasion of fitting an RF3, if one intends to produce before and after graphs then most relevant ones would be those for QLN and not SNR . . . ;)
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Just a quick comment.
On the occasion of fitting an RF3, if one intends to produce before and after graphs then most relevant ones would be those for QLN and not SNR . . . ;)
Ooops, here we go!
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:hmm: Hmm . . . Not too easy to compare as the scaling on the x-axis is different. :-X
However to this sleepy cat's eye, there appears to be some improvement at the higher frequencies. :)
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Unfortunately due to the attenuation at my line length, those frequencies are not active :(
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The RF3 tried to cut out a lot of noise but allows the DSL frequencies through. (the rf2 filter is similar or identical to the one on the bell wire on the newer filtered face plates so filtering out the bell wire noise greatly just as 2 of them, one on each leg does in an RF2)
So lets try and come up with an RFI filter at 7.206 to 7.464 Mhz that effects the masses on VDSL2 can it be done ? no it can't if you try to subdue the frequencies by the filtering method there is always going to a negative effect at the receiving end, so if you have RFI on broadband then there is nothing we can do about it and I don't even think BT Openreach can fix it, it's all down to the Laws of Physics and that can't be changed by no man ;)
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Unfortunately due to the attenuation at my line length, those frequencies are not active :(
and also the two QLN are of different times one is going into RFI peak time and the other is coming out of RFI peak time, though RFI peak times are dependant on where you live (North and South in the UK.
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On an allied note there appears to have been a slight drop in the number of FEC errors and the number of bitswaps.
Maybe it will earn me a reduction in interleaving level (currently 1065/90)?
As noted earlier I will let it rest a while and see what happens DLM wise.
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On an allied note there appears to have been a slight drop in the number of FEC errors and the number of bitswaps.
Maybe it will earn me a reduction in interleaving level (currently 1065/90)?
As noted earlier I will let it rest a while and see what happens DLM wise.
yes please monitor your line over a few weeks and let us RF3 owners know if it's worth installing.
Thanks Semmy
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An RF3 is not really a filter . . . as in tuned to a specific spot frequency or a band of frequencies. It is a pair of chokes, wound on a common former, which act by blocking any common mode signal whilst allowing the differential mode signal to pass.
Remember that an xDSL circuit operates in differential mode. So to minimise the effect of common mode RFI, the two legs of the circuit should be balanced. The better the balance, the less the effect of RFI upon it.
JGO (http://forum.kitz.co.uk/index.php?action=profile;u=6929) has provided a good description (http://forum.kitz.co.uk/index.php?topic=13473.msg253918) of an RF3's mode of operation. :)
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Unfortunately due to the attenuation at my line length, those frequencies are not active :(
Do you have the raw, tabular, data from which those two graphs were produced? If yes, then I would be able to produce the two graphs with identical x-axes which would allow simple comparison, by eye.
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An RF3 is not really a filter . . . as in tuned to a specific spot frequency or a band of frequencies. It is a pair of chokes, wound on a common former, which act by blocking any common mode signal whilst allowing the differential mode signal to pass.
Remember that an xDSL circuit operates in differential mode. So to minimise the effect of common mode RFI, the two legs of the circuit should be balanced. The better the balance, the less the effect of RFI upon it.
JGO (http://forum.kitz.co.uk/index.php?action=profile;u=6929) has provided a good description (http://forum.kitz.co.uk/index.php?topic=13473.msg253918) of an RF3's mode of operation. :)
yes I read it a few times BC and it does look like it's tuned for the lower frequencys of ADSL my RFI is coming in at the higher frequencys.
if JGO could investigate which specific spot frequency or a band of frequencies the RF3 is targeting then it would be helpful to see the specification ;D
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One last final question before I hit the sack.
What level of noise is acceptable on a quiet Iine test?
Mine has what I can only describe as a faint hiss/white noise, audible but not loud enough to interfere with voice traffic.
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. . . specific spot frequency or a band of frequencies the RF3 is targeting . . .
:wall: It isn't. It doesn't. It blocks common mode signals (as best as it can) from baseband (0 Hz) to the upper frequencies used by xDSL whilst allowing differential mode signals to pass.
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What level of noise is acceptable on a quiet Iine test?
How long is a piece of string? ;D
Mine has what I can only describe as a faint hiss/white noise, audible but not loud enough to interfere with voice traffic.
That might be the beginnings of a HR joint. The only way I can describe what one should hear when performing a QLT is to say that it should be obvious that the circuit is electrically active -- that it has a "presence".
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. . . specific spot frequency or a band of frequencies the RF3 is targeting . . .
:wall:
Don't do that BC you'll get a sore head, feck it I'll just install it and get it over and done with :lol:
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Do you have the raw, tabular, data from which those two graphs were produced? If yes, then I would be able to produce the two graphs with identical x-axes which would allow simple comparison, by eye.
Will have a look this evening after work. Alternatively what would you recommend as a useful graphing/plotting package? (ideally freeware!)
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Will have a look this evening after work. Alternatively what would you recommend as a useful graphing/plotting package? (ideally freeware!)
The simplest way, of course, is just to configure the x-axis in DSLstats appropriately and leave it set. Don't swap it about, then you will have consistent plots!
For the plotting of graphs, I make use of GNUplot (http://www.gnuplot.info/).
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Don't do that BC you'll get a sore head, feck it I'll just install it and get it over and done with :lol:
common-mode signal (http://en.wikipedia.org/wiki/Common-mode_signal)
common-mode interference (http://en.wikipedia.org/wiki/Common-mode_interference)
common-mode rejection ratio (http://en.wikipedia.org/wiki/Common-mode_rejection_ratio)
balanced and differential lines (http://en.wikipedia.org/wiki/Balanced_line#Balanced_and_differential)
differential amplifier, differential mode (http://en.wikipedia.org/wiki/Differential_amplifier#Differential_mode)
:friends:
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What a fun evening Installed BT80B RF3 it was easy going, checked the phone it's working, started up the HG612 and waited the DSL led keeps blinking after say 20 mins no connection installed the SSFP MarkII and again blinking DSL leds gave it another 20 mins still not connecting then removed BT80B RF3 and re-installed the old box and rebooted the HG612 it connects straight away ???
The phone works with BT80B RF3 but the HG612 can't get a sync :no:
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Odd. Sure it's an RF3 and not an RF2?
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Odd. Sure it's an RF3 and not an RF2?
Hmmm would it make a difference ?
as per BC's note: It blocks common mode signals (as best as it can) from baseband (0 Hz) to the upper frequencies used by xDSL whilst allowing differential mode signals to pass.
it deffinately blocks the common mode signals as why the HG612 will not SYNC on VDSL :(
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The RF2 filter is sometimes fitted to a line to mitigate the effect of radio frequency interference causing degradation to telephony audio quality. They are normally fitted as a result of a customer complaint and when strong levels of radio signals have been identified as the cause of noise on PSTN service. They are normally fitted at the customer premises but can also be found at the exchange MDF. The RF2 is designed to block High Frequency (HF) radio signals (both common mode and transverse mode). Because ADSL is a transverse HF signal (25kHz to 1.1MHz) it is inhibited by the RF2. A new design, the RF3, has replaced the RF2 which is ADSL friendly – it blocks only the common mode HF signal.
The effect of the RF2 on ADSL Broadband is to increase the downstream loss by 31dB and so can cause No Synchronisation and Loss Of Synchronisation type faults. Typically modems will train but loose synch after a few seconds.
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Whoops ...... forgot to add .......... to identify between the two, the RF2 comprises of 2 ferrite core inductors whereas the RF3 incorporates a single iron wound device.
I'm sure there's been mention of this before, but just to highlight it again.
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The RF2 filter is sometimes fitted to a line to mitigate the effect of radio frequency interference causing degradation to telephony audio quality. They are normally fitted as a result of a customer complaint and when strong levels of radio signals have been identified as the cause of noise on PSTN service. They are normally fitted at the customer premises but can also be found at the exchange MDF. The RF2 is designed to block High Frequency (HF) radio signals (both common mode and transverse mode). Because ADSL is a transverse HF signal (25kHz to 1.1MHz) it is inhibited by the RF2. A new design, the RF3, has replaced the RF2 which is ADSL friendly – it blocks only the common mode HF signal.
The effect of the RF2 on ADSL Broadband is to increase the downstream loss by 31dB and so can cause No Synchronisation and Loss Of Synchronisation type faults. Typically modems will train but loose synch after a few seconds.
Look Blacksheep if you look at your copy and paste text it refers to ADSL not one mention of VDSL or as BC puts it xDSL there is A and V there is a difference ;)
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Have you swallowed a 'Cheeky stard' pill, NS ??
We know there's ADSL and VDSL, but VDSL's D1 band-plan utilises the ADSL frequencies that wouldn't work with the RF2 fitted. Would it not be the same when fitted to a VDSL circuit ?
Would it not be easier to say if you have an RF2 or an RF3 ?? ;)
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Have you swallowed a 'Cheeky stard' pill, NS ??
We know there's ADSL and VDSL, but VDSL's D1 band-plan utilises the ADSL frequencies that wouldn't work with the RF2 fitted. Would it not be the same when fitted to a VDSL circuit ?
Would it not be easier to say if you have an RF2 or an RF3 ?? ;)
The RF2 faceplate works on NTE5 VDSL but the BT80 RF3 blocks the signal to HG612 VDSL yet the Voice works (phone is working) your the Engineer so I am looking for an explanation into why this could be the case.
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My job's to fit them if needed, not work out the applied physics behind them. I thought this was more your own department ?
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NS, it appears to be just the RF3 you have that blocks the VDSL not all RF3's as quite clearly mine functions with it fitted.
Is it possible you have a faulty RF3?
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My job's to fit them if needed, not work out the applied physics behind them. I thought this was more your own department ?
Sorry I don't meen to come across as being cheeky on the Kitz forum it's just i started to install this BT80 RF3 at 18:45 and then finding it does not work on VDSL and having to install to previous state 20:30 so I am fed up with and yes it looks like I was used as the guinea pig for VDSL it's not the first time ;)
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NS, it appears to be just the RF3 you have that blocks the VDSL not all RF3's as quite clearly mine functions with it fitted.
Is it possible you have a faulty RF3?
send me a PM where you bought the BT80 RF3
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Thanks Semmy have purchased an other one from your PM thanks.
Have a question, do you also have the SSFP MarkII installed at the NTE5 ?
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What a fun evening Installed BT80B RF3 it was easy going, checked the phone it's working, started up the HG612 and waited the DSL led keeps blinking after say 20 mins no connection installed the SSFP MarkII and again blinking DSL leds gave it another 20 mins still not connecting then removed BT80B RF3 and re-installed the old box and rebooted the HG612 it connects straight away ???
The phone works with BT80B RF3 but the HG612 can't get a sync :no:
:'( I can only assume that the RF3 is faulty . . . (Or the seller saw you coming and decided to get rid of an old RF2. :o )
If it helps, I purchased my RF3 from here (http://www.run-it-direct.co.uk/BT80BRF3.html).
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I do indeed have the MkII SSFP fitted as well.
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What a fun evening Installed BT80B RF3 it was easy going, checked the phone it's working, started up the HG612 and waited the DSL led keeps blinking after say 20 mins no connection installed the SSFP MarkII and again blinking DSL leds gave it another 20 mins still not connecting then removed BT80B RF3 and re-installed the old box and rebooted the HG612 it connects straight away ???
The phone works with BT80B RF3 but the HG612 can't get a sync :no:
:'( I can only assume that the RF3 is faulty . . . (Or the seller saw you coming and decided to get rid of an old RF2. :o )
Who knows ! here is the inside of the RF3
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Well that definitely looks like an RF3 . . . :-\
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Yup, looks the same as mine too.
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Yes I know its and RF3, have asked for a refund on flebay and used your link and placed an order, if the next one do's not work then i am afraid i'll give up on this RF3 DIY job as NA , at least i have the SSFP MarkII installed again at the NTE5 socket.
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Hi Guys after installing BT80 RF3 and having to remove due suspect faulty part yesterday my stats have never been so bad, have had 3 retrains since, it looks like I have Interleaving induced on the US and DS sync is low.
I deffo have to postone any attempts to install a working BT80 RF3 unit and avoid turning off HG612 for a few weeks the DLM has got it claws firmly embedded on my circuit.
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>:( Ouch! :'(
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>:( Ouch! :'(
Suppose theres no gain without pain :) yet there would be less pain if Flebay had given me a working unit at the start >:(
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Hi Guys after installing BT80 RF3 and having to remove due suspect faulty part yesterday my stats have never been so bad, have had 3 retrains since, it looks like I have Interleaving induced on the US and DS sync is low.
Oh dear!!!
DLM really has been quite aggressive there hasn't it? :o
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Oh dear!!!
DLM really has been quite aggressive there hasn't it? :o
partly my fault as when RF3 was not syncing with HG612 I then turned off modem in the proper way and replaced MKI with MKII and again HG612 was not getting any sync, then turned off modem again to removed RF3 so thats 3 power offs in 1 hour 45 mins, though I did have Power line Adapter issues 48 hours before, which cause the DLM to act on my line.
So all in all to many HG612 power offs in 3-4 days
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So, finally got around to messing around with a couple of graphing packages (Graph - Freeware, windows based and easy for a noob like me to manipulate the data into -http://www.padowan.dk/ ) and I get the following.
What a difference a week makes!
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So, finally got around to messing around with a couple of graphing packages (Graph - Freeware, windows based and easy for a noob like me to manipulate the data into -http://www.padowan.dk/ ) and I get the following.
What a difference a week makes!
Apologies for the reversed colours in the first graph!
Yes I saw your Graphs before you removed it from the site, and it did not look good, so could you stick with HG612_Modem_stats or DSLstats to stop this confusion.
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Sorry NS but unless I have missed the option in DSL stats how else can you display comparative graphs?
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Sorry NS but unless I have missed the option in DSL stats how else can you display comparative graphs?
You could ask the developers of DSL stats to add this function in on there next update ;)
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TBH what I am looking at now is a package that will graph in a third dimension so you can display the numbers over time as well, just not quite working yet 8)
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we have identified why the BT80 RF3 unit did not work for me, and the reason is I connected the wires to terminals wrongly there are three screw in terminal A wire, Earth and B wire it looks like I connected A wire and used Earth (B) so thats why telephone worked and the reason why the HG612 would not sync.
Full apologies to Blacksheep and Burakkucat for my mistake, I hope in time you will forgive me for my silly outburst on the Kitz forum :-[
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"Outburst"? ???
I didn't notice one -- silly or otherwise -- and I suspect the same goes for Black Sheep. :)
Coincidently I have just posted some details and a photograph to a new thread, titled Connecting a BT80B-RF3 (http://forum.kitz.co.uk/index.php?topic=13976.msg262670).
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Installed the BT80B RF3 45 minutes ago and it's working fine, and I am using the correct terminals this time, Just thought as I am banded for a while I'll get this fitted and start collecting some stats.
At the moment stats have not changed due to Banding, all I can say is the attenuation has increased by a minuscule amount of 0.2 (SSFP MkII 0.1 + RF3 0.1 = 0.2) ;)
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Any idea how long it will take for banding to be relaxed?
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Any idea how long it will take for banding to be relaxed?
It normally takes upto 14 days depending on how bad the errors were, sometimes 4-5 if its just small burst of errors, I would avoid any FTTC Modem power downs during this period or you just keep setting back the time before banding is relaxed by the DLM.
So for me it will be the 30th of May :(
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Installed the BT80B RF3 45 minutes ago and it's working fine,
Purrfect. :)
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Purrfect. :)
Cheers BC
I'll give you sneak preview into SNR and Tones it looks a mess at the moment as it's early days things should improve over time me hopes ;)
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The one graph that could be revealing is the QLN, created from the data collected at synchronisation time. :-\
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The one graph that could be revealing is the QLN, created from the data collected at synchronisation time. :-\
OK i'll upload the Hlog, a new Sync came in this morning at 05:55 due to having to turn off HG612 yesterday to install RF3 unit, the DLM has started to relax my line stats somewhat.
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So a lot of us are suffering from this issue to differing degrees, and it doesn't seem like much can be done to filter it from the signal. Would it not be more effective to try and find a way of preventing it getting into the signal/line in the first place?
Discussed to death many, many, many times .... LL. :)
It's all down to the bottom line of the accountants sheet. We're pumping frequencies down cables that were lain decades ago, that simply were not designed to carry them.
Of course, FTTP is the ultimate answer, but it is NOT going to happen overnight.
I can't be bothered trying to reference it, but I read some years ago about some Oz scientist who managed to pump some astounding DSL speeds over bog-standard twisted copper pairs. He had basically eliminated all noise, but in laboratory conditions.
The problem we have as human beings is the fact we are needy and greedy. Just over a decade ago we could only expect 0.5Meg speeds, and today we can get 80Meg ....... but we still feel the need to get more. nothing wrong with that, it just won't happen right here ... right now like some would like it to be.
It still amazes me even now, when I attend a task and the EU has months of historical DSL stats and has collated information to say he should have 0.3 Meg more DS speed and his 'Ping' has risen by 2mS. I often think to myself, if you'd spent more time cleaning the disgusting pig-sty of a house, or got off your arse and got a job, then you might not be as obsessed with this ridiculous request you have got me to site for !!!
The difference wouldn't make any difference, when they are browsing .... if you follow my drift ?? :)
you visited me then ;)
just kidding. 0.3meg sync obviously is a lot if the sync is only 0.4meg, but if its say 60meg, then 0.3 as you say is nothing, so its a % game, and I wouldnt call an engineer for 2ms latency.
However one of the engineers who visited me I let him use the toilet, and after he left I was a bit embarrased as my bathroom needed cleaning and was a mess, so I did spend time to clean it up after he left. Rest of mny house isnt exactly spick and span either, so your comment is amusing as I wonder how often engineers visit a place and have to keep their mouth shut out of politeness when its a tip.
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Just had a large thunderstorm that lasted 1 hours so unfortunately the 2 RF units where not able to subdue the effect of static discharges, it was fun to see the errors climbing during this event the CRC errors went wild. :o
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Is it going to be another year where half the country is having storms but my area is bone dry?
I would love a storm, the heat and stuffyness here is unbearable, pure sun, no wind not even a breeze.
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to test lines I had a a pair of test leads with an nte5 and a DSL face plate so I could plug my test modem in. As for REIN we had to fit an RF3 as a knee jerk attept to cure the problem & had an rf3 in the NTE back box connected by an 8 pole DT switch. so I could test with and without the rf3 (testing without totally isolated the RF3 so it wasnt even Teed off)
So I could always test with and without an rf3 at the flick of a switch on any task. I have got to say that the number of times it made any difference was very rare. just a couple of percent at a guess.
What I'm trying to sum up is that with DSL faults, its very easy to get transfixed by one possibility to cause an issue where the problem lies elsewhere or a couple of other places.
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Is it going to be another year where half the country is having storms but my area is bone dry?
I would love a storm, the heat and stuffyness here is unbearable, pure sun, no wind not even a breeze.
be careful on what you wish for Chry, I am on my 15th year collecting weather stats and it's telling me this may be a wet & humid summer in the middle to north of the UK and the south will be hotter than Ibiza then in the end of July you will have flash floods and strong winds.
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What I'm trying to sum up is that with DSL faults, its very easy to get transfixed by one possibility to cause an issue where the problem lies elsewhere or a couple of other places.
Yes Ezzer I do have the beginning of an HR fault, but I am doing all this to stop the BT Openreach engineer running around in circles to cure the problem, I am 100% sure it's not down to crosstalk and it looks like RFI may not be the cause but it's in the early stage of investication.
I have two other things to try and it will cause me inconvenience and that is to bypass the FTTC Data socket and setup the HG612 at the Master Socket the other is to ring up BT and ask for an engineer to visit my home.
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Sorry NewtronStar, I was skimming through most posts so I didn't note the HR issue. Although Like many here I do sometimes answer with half an eye towards anyone else reading the same post. :)
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Sorry NewtronStar, I was skimming through most posts so I didn't note the HR issue. Although Like many here I do sometimes answer with half an eye towards anyone else reading the same post. :)
No worrys Ezzer it won't show up in this thread, but I do have other posts on the forum that delves into possible beginnings of an HR fault ;)
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Another retrain at 00:56 and TBH lost count in how many i've had in the last 5 days the last one was this morning at 07:52 it must be like 12 this is unusual even for me :-\
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Well, a DLM resync this morning cost me my fastpath connection with a 3 Mbps reduction in DS sync speed.
I can see the start of the 'problem' at around 2 pm yesterday, but as I had accidentally disabled the logging task last night by messing about with GUI/ini file settings to deal with a couple of user reported issues, I can't quite see the full story.
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Well, a DLM resync this morning cost me my fastpath connection with a 3 Mbps reduction in DS sync speed.
ouch :(
sorry to hear that BE1 , it seemed like it was holding well for a while.
incidently , im still waiting for a retrain , stats have remained around the same throughout the past 11 days.
( again , cant post any graphs becouse my server had a windows update and shut itself down a few days ago)
Stats recorded 20 May 2014 09:11:48
DSLAM/MSAN type: IFTN:0xb203 / v0xb203
Modem/router firmware: AnnexA version - A2pv6C035m.d22g
DSL mode: VDSL2
Status: Showtime
Uptime: 11 days 9 min 18 sec
Resyncs: 0 (since 20 May 2014 08:53:06)
Downstream Upstream
Attenuation (dB):
Connection speed (kbps): 50706 20000
SNR margin (dB): 6.3 6.5
Power (dBm): 13.1 6.4
Interleave depth: 993 1
INP: 3.00 0
RSCorr/RS (%): 2.1242 0.9185
RSUnCorr/RS (%): 0.0169 0.0000
ES/hour: 0.29 5.18
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Well, a DLM resync this morning cost me my fastpath connection with a 3 Mbps reduction in DS sync speed.
I can see the start of the 'problem' at around 2 pm yesterday, but as I had accidentally disabled the logging task last night by messing about with GUI/ini file settings to deal with a couple of user reported issues, I can't quite see the full story.
I don't know BE1 is this my 3rd retrain in under 24 hours the last one occured at 19:19 this evening starting to wonder by installing the MKII and BT80 RF3 is the cause of all this :-\
it keeps going from retrain reason 1 to 4 then back to 1 ?
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According to something asbokid posted a long time ago, these are the retrain reasons:-
Retrain Reason Los Detector 0
Retrain Reason Rdi Detector 1
Retrain Reason Negative Margin 2
Retrain Reason Too Many Us FEC 3
Retrain Reason CReverb1 Misdetection 4
Unless I'm mistaken, your sync speeds are improving with each resync aren't they?
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According to something asbokid posted a long time ago, these are the retrain reasons:-
Retrain Reason Los Detector 0
Retrain Reason Rdi Detector 1
Retrain Reason Negative Margin 2
Retrain Reason Too Many Us FEC 3
Retrain Reason CReverb1 Misdetection 4
Unless I'm mistaken, your sync speeds are improving with each resync aren't they?
Yes the sync has been improving from 19999Kbps to 24397Kbps and then 27397Kbps and then the US was but back onto fastpath, and yes I see what your getting at because I lost so much due to my stupid BT80 RF3 wireing mistake the DLM is having to work overtime to get me back to where it thinks was the norm for my line.
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Done as much as I can at my end to see if the RF3 helps on VDSL2 circuit, as for the Tones going missing in the evening there has been less fragmentation on the tones in question but it's still noticeable, one thing that is good is the SNR dB at the higher frequency tones (D2) has increased from 6dB to 9-12 dB (more bits in those tones) and the CRC errors have been very low, though I am wondering as the INP rose from 3.00 to 8.00 a few weeks ago this may be the reason for fewer CRC errors.