View Full Version : Digital Attenuator needed ???
Here's some background for the past few weeks I have been having real issues with my BB connection. I need to reboot the SACM all the time and the connection speed is about as fast as dialup and I still need to reboot all the time.
We had Virgin round at the weekend who checked my connection and told me that the problem is that the attenuator I have going into the house, which they said is an analogue attenuator and that needs to be replaced with a digital attenuator and then my signal levels should be ok and I should have a proper connection.
I used to have my BB through the STB and it's only since the V+ box went in a few months ago that I got a SACM.
What I want to find out is if I didn't have a digital attenuator all this time does this mean for years I haven't been getting the speed I should have ?
Graham M
05-11-2007, 11:30
I couldn't tell you what the difference between a digital and analogue attenuator is, if there is even a difference? I think you've been fobbed off to be honest, but someone will come along and prove me right or wrong I'm sure
a bit more background info here.
We were told the signal levels to our house we too low and they were going to fit a new cable going into the house as they thought that was the problem. They were going to fit a "RG11" cable as we have one with smaller bandwidth than that.
They couldn't do that at the time but the engineer took a look and said we just needed an attenuator fitted and that would solve the problem.
As i'm going to ring Virgin I want to find out if this means i've had lower signal levels for years or just since the V+ box was installed.
Hope they not fobbed me off as have had poor BB service for 3 weeks already
Graham M
05-11-2007, 11:57
An Attenuator is a bit like a resistor in an electrical circuit, it lowers the signal level as beleive it or not, higher signal levels can be as bad, if not worse as lower signal levels.
monkey2468
05-11-2007, 12:13
Goto 192.168.100.1 password/login root/root, and post your signal levels.
Could be that what is required is a forward path attenuator or FPA. These reduce the signal going to the box but leave the one coming back alone - clever stuff! We have a 6dB FPA at our SACM.
This would agree with the description of a 'digital' attenuator as the return path is important for the operation of a digital STB.
Graham M
05-11-2007, 12:16
Yep very true Altis, hadn't thought about that, the Return path is quite important for Broadband ;)
i'll post the signal levels tonight if I get a good enough connection.
About to ring CS as they was meant to be fitting this so will see how it goes.
Thanks for the help anyway
Graham M
05-11-2007, 12:41
If you can't get any noise out of em, I have a couple spare rattling around at home :) Best get em from the engineer however as they can measure the signal exactly.
Brilliant.
I phoned up CS, who are meant to be phoning me back anyway, and they had no details of this written on the account at all. They've taken my number and said they will call me later back later.
Also mentioned that i'm paying for this and not getting the service i'm paying for either
here's the downstream levels
Downstream Lock : Locked
Downstream Channel Id : 1
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -6.8 dBmV
Downstream SNR :
Here are the upstream levels
Upstream Lock : Locked
Upstream Channel ID : 3
Upstream Frequency : 42800000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 58.0 dBmV
Upstream Mini-Slot Size : 2
Here's the upstream burst in
Req
Init Maint
Per Maint
Short Data
Long Data
(1)
(3)
(4)
(5)
(6)
Modulation Type QPSK QPSK QPSK QPSK QPSK
Differential Encoding Off Off Off Off Off
Preamble Length 64 128 128 100 80
Preamble Value Offset 396 6 6 396 396
FEC Error Correction (T) 0 5 5 3 9
FEC Codeword Information Bytes (k) 16 34 34 78 232
Scrambler Seed 338 338 338 338 338
Maximum Burst Size 0 0 0 35 254
Guard Time Size 8 48 48 25 134
Last Codeword Length Fixed Fixed Fixed Short Short
Scrambler on/off On On On On On
I took this at a time when the modem was working though so don't know if levels drop when I get a poor connection
Axegrinder
06-11-2007, 09:47
Your upstream is quite high, that maybe the reason why your connection is dropping. between 30 and 55 is are the limits.
evilmonkey
06-11-2007, 14:54
a bit more background info here.
We were told the signal levels to our house we too low and they were going to fit a new cable going into the house as they thought that was the problem. They were going to fit a "RG11" cable as we have one with smaller bandwidth than that.
They couldn't do that at the time but the engineer took a look and said we just needed an attenuator fitted and that would solve the problem.
As i'm going to ring Virgin I want to find out if this means i've had lower signal levels for years or just since the V+ box was installed.
Hope they not fobbed me off as have had poor BB service for 3 weeks already
Heres the problem if your signal was too low why would they fit an attenuator! Attenuate meaning to reduce! Also policy changed 3 years ago they arent meant to use attenuators any more as it messes up the signals accross most of the network.
well i've had the engineer back today and he's just sad the same thing. An attenuator will reduce my signal levels and it's already too low
Seems the engineers from Sat told Virgin that they did fit the RG11 cable to the house when they didn't and then just told me a load of rubbish. Seems they might get the sack for that but that still leaves me with a rubbish connection.
I do still need the new cable to that needs to be booked in again and I think the port needs to be unblocked or something as that's why it wasn't done at the weekend
Virgin are meant to be calling me back so wonder if that will happen. Also no offer of a refund yet :mad:
Downstream Receive Power Level : -6.8 dBmV (to low )
Upstream transmit Power Level : 58.0 dBmV (to high )
these to are one of your main problems
if my memory serves right signal levels are to low
can you see a small type of cabnet near you house if so how far estimte (black,brown
or green in colour )
your on qam 64 so bb should a max of -6
the levels on the three tuners on the V+ box are too low too. Two of them are at -11
The engineer said no point fitting an attenuator as that will make the signal worse.
The cab is about 100 yards or more away
Graham M
06-11-2007, 21:48
So did the engineer put you on a higher signal feed?
So did the engineer put you on a higher signal feed?
the engineer said that basically they need to come back and do the RG11 cable into the house so we have a bigger pipe.
Are engineers able to raise the signal levels themselves ? Apart from testing the signal he didn't really do anything himself.
No call back from Virgin yet either :mad:
Inside the green street cabinet are a series of 'taps' arranged in groups of different signal levels. It could be that, in your cabinet, there are no higher taps free for your cable or you are already on the highest tap and the signal is still too weak.
well we've had the RG11 cable done and the connection still seems slow.
Here are my new signal levels
Downstream Lock : Locked
Downstream Channel Id : 1
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -7.6 dBmV
Downstream SNR : 32.8 dB
Upstream Lock : Locked
Upstream Channel ID : 3
Upstream Frequency : 42800000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 59.0 dBmV
Upstream Mini-Slot Size : 2
Mick Fisher
10-11-2007, 22:27
At 59.0 dBmV your upstream transmit power level is STILL too high. How pathetic is that?
homealone
10-11-2007, 22:47
At 59.0 dBmV your upstream transmit power level is STILL too high. How pathetic is that?
on a scale of 1-10 it is a 10
for a re-pull to result in a level issue is inexcusable, in my opinion :erm:
An RG11 will attenuate less at the higher frequencies, so really the Re-pull wouldn't improve the downstream signal into your SACM, but it would benefit the frequencies from 600-750mhz. This will improve the signal levels for your STB. As already pointed out, your drop cable needs to be put on a tap that will give you more signal, this will improve the return signal as well,(thats if there is any tap ports available to give you higher signal output).
Unfortunately again this is down to service tech's not having much of a clue,poor training and equipment that is not satisfactory.
How many splitters do you have in the house or the grey box outside? as these will also put more attenuation on the return path.
just the one splitter between the cable modem and STB. I tried taken that out and going straight to SACM but that didn't make much difference.
Wonder if Virgin will call me on Monday to see if the problem is resolve :erm:
Looks like this problem is just going to drag on and on at the moment
us phoned CS about this as strangely Virgin didn't call me back to see if this resolved the problem.
First person cut me off which was great, second person said I need to call India. My company doesn't let me dial 090 numbers so the only time I can call is when I get in and they are never there then.
As i've already had an engineer round to check the signal levels and they are poor I don't really want to go through dealing with India again.
Seems like this is just going to go on and on and on
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