Kitz Forum
Broadband Related => ADSL Issues => Topic started by: Loading on April 04, 2014, 07:52:50 PM
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Just wondering how easy is is to detect a bridge tap, as this can affect adsl more so than the phone? Reducing impedance, reducing signal strength.
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Detecting it by what manner ?? Graphing scripts, or an actual hand-held meter ?? :)
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Just wondering how easy is is to detect a bridge tap
Just look at the value of Hlog versus frequency. ;)
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How would that be done B*cat? Also how do you test continuity on the line, what value should it show? When I test i get -508?
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If you are using a modem which provides the appropriate data, harvest the data and plot it as a graph.
Using a Huawei HG622 I obtain the following raw data --
[Duo2 ~]$ telnet ap
Trying 192.168.1.254...
Connected to ap.
Escape character is '^]'.
-------------------------------
-----Welcome to ATP Cli------
-------------------------------
Login: admin
Password:
ATP>sh
BusyBox vv1.9.1 (2011-09-27 11:55:09 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.
# xdslcmd info --Hlog
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 8000
Max: Upstream rate = 1064 Kbps, Downstream rate = 5884 Kbps
Channel: INTR, Upstream rate = 1020 Kbps, Downstream rate = 5572 Kbps
Tone number Hlog
0 -96.2500
1 -96.2500
2 -96.2500
3 -96.2500
4 -96.2500
5 -96.2500
6 -96.2500
7 -24.6875
8 -23.7500
9 -23.5625
10 -24.1875
11 -24.5625
12 -25.0625
13 -25.2500
14 -25.5625
15 -26.1875
16 -26.7500
17 -27.2500
18 -27.7500
19 -28.3750
20 -29.0000
21 -29.5000
22 -30.0000
23 -30.8750
24 -32.0000
25 -33.0625
26 -34.1875
27 -35.0625
28 -36.0000
29 -37.1875
30 -38.6875
31 -40.5000
32 -53.9375
33 -52.3750
34 -50.8125
35 -49.3125
36 -47.8125
37 -46.3750
38 -45.0000
39 -43.6875
40 -42.4375
41 -41.3750
42 -40.4375
43 -39.7500
44 -39.2500
45 -39.0625
46 -39.0625
47 -39.2500
48 -39.5625
49 -39.8125
50 -40.1875
51 -40.5625
52 -40.8750
53 -41.1875
54 -41.5000
55 -41.8125
56 -42.1250
57 -42.4375
58 -42.6875
59 -42.9375
60 -43.1875
61 -43.4375
62 -43.6875
63 -43.9375
64 -44.1250
65 -44.3750
66 -44.5625
67 -44.7500
68 -45.0000
69 -45.1875
70 -45.4375
71 -45.6250
72 -45.8125
73 -46.0000
74 -46.2500
75 -46.4375
76 -46.6250
77 -46.8125
78 -47.0000
79 -47.1875
80 -47.3750
81 -47.6250
82 -47.8125
83 -48.0000
84 -48.1875
85 -48.4375
86 -48.6250
87 -48.8125
88 -49.0000
89 -49.2500
90 -49.4375
91 -49.6250
92 -49.8125
93 -50.0625
94 -50.2500
95 -50.4375
96 -50.6875
97 -50.8750
98 -51.0625
99 -51.2500
100 -51.5000
101 -51.7500
102 -51.9375
103 -52.1875
104 -52.3750
105 -52.6250
106 -52.8125
107 -53.0000
108 -53.2500
109 -53.4375
110 -53.6875
111 -53.8750
112 -54.0625
113 -54.3125
114 -54.5625
115 -54.7500
116 -55.0000
117 -55.2500
118 -55.4375
119 -55.6875
120 -55.8750
121 -56.1250
122 -56.3125
123 -56.5625
124 -56.7500
125 -57.0000
126 -57.1875
127 -57.4375
128 -57.6875
129 -57.8750
130 -58.1250
131 -58.3125
132 -58.5000
133 -58.7500
134 -59.0000
135 -59.1875
136 -59.4375
137 -59.6250
138 -59.8125
139 -60.0000
140 -60.2500
141 -60.4375
142 -60.6875
143 -60.8750
144 -61.0625
145 -61.3125
146 -61.5625
147 -61.7500
148 -62.0000
149 -62.1875
150 -62.3750
151 -62.5625
152 -62.8125
153 -63.0625
154 -63.1250
155 -63.3750
156 -63.6250
157 -63.8750
158 -64.0625
159 -64.2500
160 -64.4375
161 -64.6875
162 -64.9375
163 -65.1250
164 -65.3125
165 -65.5000
166 -65.6875
167 -65.8750
168 -66.0625
169 -66.2500
170 -66.5000
171 -66.7500
172 -66.9375
173 -67.1875
174 -67.2500
175 -67.5625
176 -67.6875
177 -67.8750
178 -68.1250
179 -68.3125
180 -68.5625
181 -68.7500
182 -68.9375
183 -68.9375
184 -69.3125
185 -69.5625
186 -69.7500
187 -70.0000
188 -70.1250
189 -70.3750
190 -70.5625
191 -70.7500
192 -71.0000
193 -71.1875
194 -71.3125
195 -71.6875
196 -71.7500
197 -72.0000
198 -72.2500
199 -72.3750
200 -72.6250
201 -72.8750
202 -72.9375
203 -73.3750
204 -73.4375
205 -73.5625
206 -73.8750
207 -74.0000
208 -74.1875
209 -74.4375
210 -74.5000
211 -74.8750
212 -75.0000
213 -75.1250
214 -75.3750
215 -75.5625
216 -75.8125
217 -75.9375
218 -76.1875
219 -76.3750
220 -76.6250
221 -76.7500
222 -77.0625
223 -77.0625
224 -77.3125
225 -77.4375
226 -77.7500
227 -77.8125
228 -78.0625
229 -78.1875
230 -78.4375
231 -78.6250
232 -78.8125
233 -78.9375
234 -79.2500
235 -79.1875
236 -79.3750
237 -79.6875
238 -79.6875
239 -79.9375
240 -80.1875
241 -80.2500
242 -80.4375
243 -80.9375
244 -80.7500
245 -81.1250
246 -81.3125
247 -81.3125
248 -81.6250
249 -81.9375
250 -82.3750
251 -82.6875
252 -83.2500
253 -83.4375
254 -83.8750
255 -84.0000
#
The graph, plotted from the above, is attached below. The notch, centred at tone 32 is not the result of a bridging tap but is just the transition between US and DS bands.
If you own an appropriate HHT, connect it to the line and instruct it to display the Hlog graph or perform a TDR measurement on the pair.
Also how do you test continuity on the line, what value should it show? When I test i get -508?
Sorry, I do not understand what it is that you are asking. :no: Would you please rephrase the question?
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adsl info --Hlog
adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 760 Kbps, Downstream rate = 2048 Kbps
Channel: INTR, Upstream rate = 448 Kbps, Downstream rate = 1856 Kbps
Tone number Hlog
0 -136.1250
1 -123.1250
2 -122.0000
3 -122.0000
4 -120.7500
5 -116.1250
6 -117.4375
7 -115.8750
8 -126.1250
9 -133.0625
10 -122.0000
11 -117.4375
12 -117.5000
13 -118.0000
14 -120.1250
15 -126.1250
16 -126.1250
17 -123.1250
18 -121.0000
19 -119.1250
20 -114.3750
21 -123.5625
22 -118.9375
23 -115.2500
24 -108.6875
25 -110.9375
26 -104.8125
27 -103.5000
28 -96.9375
29 -87.2500
30 -80.3750
31 -74.5000
32 -69.5000
33 -65.3750
34 -62.0625
35 -59.5625
36 -57.8125
37 -56.7500
38 -56.0625
39 -55.7500
40 -55.6875
41 -55.7500
42 -55.9375
43 -56.2500
44 -56.5625
45 -56.8750
46 -57.1875
47 -57.5625
48 -57.9375
49 -58.3750
50 -58.7500
51 -59.1250
52 -59.5000
53 -59.9375
54 -60.3125
55 -60.6875
56 -61.1250
57 -61.5625
58 -61.9375
59 -62.3125
60 -62.7500
61 -63.1250
62 -63.4375
63 -63.8750
64 -64.2500
65 -64.6250
66 -65.0625
67 -65.3750
68 -65.8125
69 -66.1875
70 -66.5625
71 -67.0625
72 -67.4375
73 -67.8750
74 -68.3125
75 -68.7500
76 -69.1875
77 -69.5625
78 -70.0000
79 -70.3750
80 -70.8750
81 -71.3125
82 -71.6875
83 -72.0625
84 -72.5000
85 -72.9375
86 -73.3750
87 -73.8125
88 -74.2500
89 -74.6875
90 -75.0625
91 -75.5000
92 -75.9375
93 -76.3125
94 -76.6875
95 -77.0625
96 -77.3750
97 -77.8125
98 -78.1875
99 -78.5000
100 -78.9375
101 -79.3125
102 -79.6250
103 -80.0000
104 -80.3750
105 -80.6250
106 -81.0625
107 -81.3750
108 -81.7500
109 -82.1875
110 -82.4375
111 -82.8125
112 -83.3125
113 -83.6875
114 -84.0625
115 -84.3750
116 -84.6875
117 -84.8125
118 -85.3125
119 -86.0000
120 -86.2500
121 -86.4375
122 -87.0625
123 -87.5000
124 -87.5625
125 -88.3750
126 -88.4375
127 -88.8750
128 -89.5000
129 -89.6875
130 -90.2500
131 -90.5625
132 -90.8125
133 -91.4375
134 -91.7500
135 -91.8125
136 -92.9375
137 -92.6250
138 -93.6250
139 -93.8125
140 -94.1875
141 -94.9375
142 -94.5000
143 -95.2500
144 -84.3125
145 -96.3125
146 -96.1875
147 -96.1250
148 -96.6875
149 -97.5625
150 -98.0625
151 -98.5000
152 -99.4375
153 -97.9375
154 -99.8125
155 -99.8125
156 -100.0000
157 -101.7500
158 -101.6250
159 -101.5625
160 -98.8750
161 -101.2500
162 -102.1875
163 -102.3125
164 -102.3750
165 -103.4375
166 -103.2500
167 -103.4375
168 -102.9375
169 -103.8750
170 -105.8125
171 -105.6250
172 -105.5000
173 -104.0000
174 -104.3750
175 -105.9375
176 -105.8125
177 -105.8750
178 -105.8125
179 -107.0625
180 -106.6875
181 -109.6875
182 -107.1875
183 -107.6250
184 -111.0000
185 -108.0625
186 -111.0000
187 -112.1250
188 -112.2500
189 -111.4375
190 -108.4375
191 -111.2500
192 -114.0625
193 -112.8750
194 -109.8750
195 -114.3750
196 -112.1250
197 -110.4375
198 -114.0625
199 -110.9375
200 -113.8125
201 -114.9375
202 -116.5625
203 -113.6250
204 -111.0625
205 -110.4375
206 -112.2500
207 -115.9375
208 -123.1250
209 -110.6250
210 -118.5000
211 -109.5625
212 -115.2500
213 -116.1875
214 -118.5000
215 -113.5625
216 -116.5625
217 -113.6250
218 -114.4375
219 -111.4375
220 -108.0000
221 -113.1250
222 -114.0625
223 -123.1250
224 -116.1250
225 -120.7500
226 -116.1250
227 -119.1250
228 -122.0000
229 -117.0000
230 -115.5000
231 -127.0625
232 -115.2500
233 -113.5625
234 -120.5625
235 -112.9375
236 -122.0000
237 -113.5625
238 -112.8750
239 -113.8125
240 -108.9375
241 -120.7500
242 -118.5000
243 -114.3750
244 -112.8750
245 -115.2500
246 -114.9375
247 -133.0625
248 -117.4375
249 -117.0625
250 -114.7500
251 -111.5000
252 -119.1250
253 -110.9375
254 -119.1250
255 -120.1250
>
Shouldn't the upstream be smoother, less spikes? On the last one why does it go up
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I am sure B*cat will confirm things but that Hlog looks fine to me. The end wiggles are just where your signal to noise gets very small or negative.
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What about the upstream, as it has spikes and sudden steepness, wouldnt that mean the upstream attenuation is changing?
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As les-70 has mentioned, at a quick glance, that Hlog curve does look more or less normal.
However when I plot that data at an identical scaling to my own, "oddities" are noticeable. See the first graph, hlog-20140406-1501.png, below. Note how that a large proportion of the curve is off the Y-axis, below -100 dB. Re-plotting the curve, giving the Y-axis further 50% in its scale, results in the second graph, hlog-20140406-1502.png, below. We now see that, in general, the overall shape of the curve is reasonable but the attenuation, across the entire range is higher. I wonder if loading's circuit makes significant use of aluminium cabling?
Two anomalous regions are the frequencies used by the US band and the spike centred at tone 144 (~623 kHz). The former can be rationalised by power cut-back, etc, as we see that loading's US synchronisation speed is capped to 448 kbps. As for the spike at tone 144, I do not know.
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What software do you use to plot the data, and it could be that when the engineer did work on the line with the tie pair, would he have used aluminium?
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No it couldn't. All tie-pairs are run in Cu (Copper), and the 'Jumper wire' used to cross-connect the PSTN/VDSL mapping is also Cu. :)
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Well there goes that theory then ;D neighbours have crackly lines, but ours isn't but still has fault symptoms
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What software do you use to plot the data,
GNUplot (http://en.wikipedia.org/wiki/Gnuplot)
And adding an additional comment to Black Sheep's reply, if what we are seeing is due to the usage of aluminium cabling then it would have to be a significant proportion of the circuit so using such cables (i.e. D-side plus E-side or, perhaps, just D-side (at a minimum)) and not such a short length as used in the exchange building -- either as tie pairs or jumpering.
Are you actually convinced that you have a fault somewhere in your circuit? (I don't want this to be taken the wrong way but it seems that you flit from one idea / one topic to another in an attempt to map a possible fault scenario onto your circuit.) :-\
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Alas, the downside to the WWW.
People go out of their way to 'find' a fault because they've read something on a forum. A bit like when you read the 'On-line doctors' symptomatic diagnosis of a certain condition, and you think to yourself, "Yeah, I've got that .... that's me that is" !!.
Not aimed at you Loading, just making a generalisation based upon personal experience. I can name all my ailments if you really want me to ?? ;D ;D ;D
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I take on board what you say, what would cause the clicking from other lines to be heard on ours, can hear router negotiating whilst using the phone if a resync is forced, hissing noise/ high pitches whistle when router connected. QLN very erratic after dark, large numbers of errors, noise margin works its way up to 15.0db after 6.0db noise margin reset, the line stats are worse after engineering work, loosing 10db upstream noise margin, attenuation increase, after I was told the only thing that was done was a tie pair mod, something's not right somewhere, it also seems that after the cabinet was supposedly flooded during the winter storms the line stats have been worse still? The clicking and hissing noise on the line must indicate a fault somewhere. It would make a nice read all of your ailments ;D
After this work was done to the line just after the attenuation was higher with dreadful speeds with the line really bad, gradually it seems to have gotten better as if we were put onto a old pair which wasn't used, but still had a fault on, the hissing?
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Ha ha, well I first developed diphtheria aged 2yrs ...... this slowly transmorgified into rickets ...... then the rot really kicked in.
But .... we haven't got time for all that just now.
Let's keep it basic, if you can hear the router kicking in when on the corded landline phone ..... and you are in the test socket and have tried a new micro-filter ..... then you have a 'HR' fault. End of.
Unfortunately, it could be anywhere between the NTE5 back-plate and the Exchange equipment. :)
After rickets came 'Black Death', which I battled for .............
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Even it its me connecting the adsl cable to the router whilst on the phone, it would still be a hr fault right? It doesn't drop whilst using the phone
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clicking from other lines to be heard on ours
Crosstalk -- possibly low insulation between your circuit and others
can hear router negotiating whilst using the phone if a resync is forced, hissing noise/ high pitches whistle when router connected.
Possibly one (or more) HR or semi-conducting joint(s).
noise margin works its way up to 15.0db after 6.0db noise margin reset,
Probably the action of the DLM in attempting to optimise the circuit's performance.
loosing 10db upstream noise margin
That will be US SNRM. Puzzling.
attenuation increase
Puzzling.
something's not right somewhere
A fair assumption.
after the cabinet was supposedly flooded during the winter storms the line stats have been worse still?
You do say "supposedly". Can you unearth the actual facts as to the occurrence or non-occurrence of what would be a significant event?
The clicking and hissing noise on the line must indicate a fault somewhere.
It certainly does. Please see above for my possible diagnosis.
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clicking from other lines to be heard on ours
Crosstalk -- possibly low insulation between your circuit and others
Have tested on neighbours phone to ring another, and can replicate the exact same clicking