Virgin Media Community

[babydean72]

hi please can some one help me out called virgin media no help ever night i lose my upstream and my download speed drops of reset router done ever thing i can still the same 

this is the info from my router#]#

Downstream bonded channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	306000000	-4.2	37	QAM 256	22
2	138000000	-3.2	38	QAM 256	1
3	146000000	-3.3	38	QAM 256	2
4	154000000	-3.3	37	QAM 256	3
5	162000000	-3.2	37	QAM 256	4
6	170000000	-3.2	38	QAM 256	5
7	178000000	-3.1	37	QAM 256	6
8	186000000	-3	37	QAM 256	7
9	194000000	-2.8	38	QAM 256	8
10	202000000	-2.8	38	QAM 256	9
11	210000000	-2.7	37	QAM 256	10
12	218000000	-2.8	37	QAM 256	11
13	226000000	-2.9	38	QAM 256	12
14	234000000	-2.9	38	QAM 256	13
15	242000000	-3.1	37	QAM 256	14
16	250000000	-3.3	38	QAM 256	15
17	258000000	-3.5	37	QAM 256	16
18	266000000	-3.5	38	QAM 256	17
19	274000000	-3.8	38	QAM 256	18
20	282000000	-4	37	QAM 256	19
21	290000000	-4.1	38	QAM 256	20
22	298000000	-4.2	38	QAM 256	21
23	314000000	-4.2	37	QAM 256	23
24	322000000	-4.3	37	QAM 256	24
25	330000000	-4.2	37	QAM 256	25
26	338000000	-4	37	QAM 256	26
27	346000000	-3.9	38	QAM 256	27
28	354000000	-3.9	37	QAM 256	28
29	362000000	-3.7	37	QAM 256	29
30	370000000	-3.7	37	QAM 256	30
31	378000000	-3.6	38	QAM 256	31

Downstream bonded channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1	Locked	37	1	0
2	Locked	38	0	0
3	Locked	38	0	0
4	Locked	37	0	0
5	Locked	37	0	0
6	Locked	38	0	0
7	Locked	37	0	0
8	Locked	37	0	0
9	Locked	38	0	0
10	Locked	38	0	0
11	Locked	37	0	0
12	Locked	37	0	0
13	Locked	38	0	0
14	Locked	38	0	0
15	Locked	37	0	0
16	Locked	38	0	0
17	Locked	37	0	0
18	Locked	38	0	0
19	Locked	38	0	0
20	Locked	37	3	0
21	Locked	38	0	0
22	Locked	38	0	0
23	Locked	37	0	0
24	Locked	37	0	0
25	Locked	37	0	0
26	Locked	37	0	0
27	Locked	38	0	0
28	Locked	37	0	0
29	Locked	37	0	0
30	Locked	37	0	0
31	Locked	38	0	0

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

0	60300000	41.3	5120	QPSK	5
1	53700000	41.3	5120	QPSK	6
2	46200000	41.3	5120	QPSK	7
3	39400000	41.8	5120	QPSK	8

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

0	ATDMA	0	0	0	0
1	ATDMA	0	0	0	0
2	ATDMA	0	0	37	0
3	ATDMA	0	0	0	0

[Anonymous]

Downstream power a little low and tonnes of T3 timeouts on channel 2. Check all cables and connections are tight and in good condition and try a pinhole reset of the hub. Also check for local faults on 0800 561 0061. 

[Client62]

Is this a UK Residential installation ?

Upstream channel modulation is QPSK (16 qam) which is lowest speed due to noise on the service, this would reduce the Upstream performance.

For a 1Gb/s service there are also usually a pair of DOCSIS 3.1 Upstream and Downstream channels.

[Anonymous]

Might be a hub 5 quirk. 

[gitty]

---

@Client62 wrote:

Upstream channel modulation is QPSK (16 qam) which is lowest speed due to noise on the service, this would reduce the Upstream performance.

---

It's even worse. QPSK is equivalent to 4-QAM. It doesn't get much worse than this.

[IPFreely]

Literally doesn't get any worse without losing lock: DoCSIS doesn't do BPSK.

To force a drop to QPSK you're talking an SNR of 12 dB and it looks like it can't even hold that on the one upstream.

It couldn't be much worse if someone had maliciously plugged a noise generator into the segment. 

[babydean72]

Hi this is a Residential installation
its the new fiber to the home that virgin are doing now

[Client62]

We have the FTTP/RFoG solution too and the Upstream modulation is supposed to be 64 QAM on all channels.

If the problems persist, call 0800 561 0061 for local errors. ( it is an automated service )

[gitty]

---

@IPFreely wrote:

Literally doesn't get any worse without losing lock: DoCSIS doesn't do BPSK.

---

Technically, as long as there is traffic flowing, it can get worse. 🙂

[babydean72]