Kitz Forum
Broadband Related => ADSL Issues => Topic started by: colchaodemola on May 12, 2007, 04:22:23 PM
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Well guys , at first i was so happy that finally some ISP had started to deliver broadband in my area, but i only get problems during day.
Before put ADSL here , i had no idea about SNR and line attenuation , but after that i started to read some explanations [thank you guys in this forum].
I have a constant problem with low snr between 11am and 5pm and a lot drops in connection , i mean A LOT .
During 5pm-11am i have an almost constant SNR margin = 12 , my attenuation is very high too ~51. While SNR=12 i can sync at 4512/512 but suddenly [not that suddenly anymore since i know almost the right hour that happens] my snr drops to ~3.9 after 11am and the problems begin. A lot of CRC ERRORS , lose syncs , and related problems, mainly a big throughput loss. I call my ISP and apparently they support staff are dumb, they appear not even know what SNR is :/ , they just keep saying the line is OK , and ask me if i am not connecting the modem in the computer`s modem port insted the ethernet port [WTF , they really think i can connect a RJ45 in a RJ11 port????? ].
I can not change ISP , `cause they are the only broadband ISP around here.
After read a few topics here i am thinking in get a netgear DG834 and with some lucky my problems with drops will at least get better. But i have a doubt , sould i take version 1 , 2 or 3 ? Which one is better with low snr ???
Thanks.
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Hi, and welcome to the forum.
An attenuation of 51 dB is quite high but should be perfectly usable. However, interference can be a problem, and this is what you seem to be suffering from. If the problem always happens at about 11:00 am then that strongly suggests a serious local source of interference from some machinery which starts up at that time. Do you, or any of your neighbours, have something like that (an exercise treadmill for example)?
You may be able to get an improvement by giving attention to your own wiring and connections - see http://www.kitz.co.uk/adsl/lowSNR.htm for some guidance.
Eric
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Now i`ve learned one new english word = "treadmill" , thanks google :)
Well, i really do not know , i live in in a building / fourth floor , i know my neighboor downstairs does not have one , and the neighboor next door neither.
i tried to look at the page you post , [i have alread looked before], but here in Brazil , telephone plugs are not like that. They are like this:
http://imgproduto.casaevideo.com.br/gif/telefixo/0264504.gif
What about the DG834 ? Will it help ? Which is the best version ?
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I'm afraid I don't know anything about the Brazilian system, but the same principles of internal wiring and interference pickup will apply. One of the DG834 series routers might help, as they are notable for their ability to hold sync at low noise margins. However it's quite unusual to have a regular big daytime drop in the noise margin (it usually drops at night for most people) and this definitely points at the probability of local electrical interference. If you can't trace the source of the interference, then you might be able to get an improvement by attention to your internal wiring (if that's permitted where you are) or by trying different ADSL filters.
Eric
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Could you recommend a very good adsl filter ?
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I don't think I can unfortunately, because the ones which are generally recommended here in the UK are supplied by British companies who don't ship to other countries. But someone else may know better.
Eric
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Hi colchaodemola
I dont really have much more to say than what roseway has already said Im afraid. The same principals would apply for adsl and the way it works, but there may be a few minor differences in equipment at the exchange and the home.
All versions of the Netgear DG834 or DG834G seem to work pretty well. For a while we continued to recommend versions 1+2 when version 3 was still new because we werent sure how the different chipset would perform. However version 3 has so far proved to be just as reliable as the older versions are on longer lines.
The fact that your problems occur during the daytime is also a bit unusual therefore I agree that it would tend to point to something local to your flat causing interference on the line. Unfortunately this could be many things - central heating pumps can be another favorite... although the list is practically endless :/
From the picture you supplied, none of the filters that we normally recommend would work with the brazilian phone system Im afraid. The UK uses British Telecom connectors, whilst that socket looks like it perhaps takes an RJ-11, ? similar to used in the USA.
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Yes , it is RJ11 :) , Now i have a big doubt, i could not find a DG834 here in brazil , and on ebay.com noone ships to brazil , but on ebay.co.uk there are a few guys that ship to brazil. I know that the power supply is incompatible , but i can built or buy another . But what about the line jack ? Is it RJ11 compatible in the modem ?
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The line jack for the modem is RJ11 compatible, yes.. and the DG834G is advertised on the Brazilian netgear site (http://br.netgear.com)
Depending on the model you get, you might need to change the Firmware in order for it to work in Brazil, but it should work :)
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hey guys , it there an easy way to force my SNR goes down ? I need to make a test and i need force SNR goes as low as possible. Some way to cause interference , some noise , AM RADIO ?
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no ideas?
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Sorry I haven't got any bright ideas, unless you can get a router which is compatible with DMT - http://dmt.mhilfe.de/
Eric
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Do you know if DG834 v3 works with DMT ?
Well , i am asking cause in DMT page has Netgear DG834GT/DG834NB/DG834PNB , but i think DG834GT has the same chipset DG834v3 , doesn`t it ?
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I does have the same chipset, yes, but whether it works or not I'm not sure, to be honest - I don't think it does - due to a limitation of the router's command set. The required adslctl command is not available on the v3 so changing SNR target isn't possible.
If you do get a router compatible with the DMT Tool, Kitz has provided a good DMT Tool tutorial here (http://www.kitz.co.uk/tute/voyager2100_DMT.htm) :)
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Hi, finally my dg834 arrived. It was almost 1 month since it was shipped from USA.
Here the status now. I got a DG834v2
before:
Att: 52 , SNR 3.9 , Drops/day ~=150 or more
now:
Att: 46 , SNR 6.1 , Drops/day = none yesterday / 1 today
i love this modem :p
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That looks good. Thanks for coming back and telling us :)
Eric
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Excellent :) Nice one
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Cool. Thanks for letting us know :thumbs:
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Hi guys , it was pretty cool while it was working , but my modem just can not sync anymore. I tried on another lines and it just can not sync.
So i have to buy another. Well , since i don`t want to import again, i was thinking, what make this modem so good to low snr is the chip right ?
So , any modem with AR7 chip will do the job as good as the netgear ?
There are a few Dlink xxxT that has AR7 chip
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Glad to hear there's a happy ending. :)
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I don't think that the performance of the DG834 is just due to the AR7 chipset. Other routers with the same chipset don't have the same performance with low noise margins, so the firmware is certainly a significant factor as well.
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I don't think that the performance of the DG834 is just due to the AR7 chipset. Other routers with the same chipset don't have the same performance with low noise margins, so the firmware is certainly a significant factor as well.
I totally agree with that statement.
By the way since your last postings - (when the v3 was new and we werent quite sure of the chipset) it has since been confirmed that v3 does have the same chipset as the v2 and seems to give similar performance results.
If you are looking at another router other than the Netgear dg834g v3 - then I wouldnt go for one with the AR7 chipset - but instead perhaps look at one of the Speedtouch routers.
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I don't think that the performance of the DG834 is just due to the AR7 chipset. Other routers with the same chipset don't have the same performance with low noise margins, so the firmware is certainly a significant factor as well.
I totally agree with that statement.
By the way since your last postings - (when the v3 was new and we werent quite sure of the chipset) it has since been confirmed that v3 does have the same chipset as the v2 and seems to give similar performance results.
If you are looking at another router other than the Netgear dg834g v3 - then I wouldnt go for one with the AR7 chipset - but instead perhaps look at one of the Speedtouch routers.
Well , i partially disagree about the firmware thing , cause even with the DG834 i stoped using the netgear firmware one week after i bought it cause there was no support to a lot of things that i need it. So i had installed openwrt , and both snr and attenuation was exactly the same of when i was using the netgear firmware , and the drops were almost none. So , at least in this case there was no difference. Is really the firmware that important , or is dlink firmwares that sucks ? Anyway , if i go with some dlink with ar7 chip i will put openwrt anyway.
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Openwrt doesn't change the ADSL chipset firmware, it changes the wireless firmware.
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Openwrt doesn't change the ADSL chipset firmware, it changes the wireless firmware.
Actually it changes, /proc/avalanche/avsar_ver shows a different version from the netgear one and dg834 has no wireless :)
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Oh my word you're right. Things have come along since I last looked. Time to play with my ancient WRT54G again I think :D
Edit - heh I can't remember the damn admin password :D I think this has Alchemy on it but gods only know.
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Hi guys , i have news ...
Today was a say of 2 big discoveries to me :)
1) I bought a dlink 500T and the modem wouldn`t sync , what a piece of crap. It showed negative SNR value and never syncs.
Well , it took me a while but i was able to install openwrt kamikaze svn from yesterday , and now i can sync just fine , SNR margin is in 6.0 just like my old DG834.
So , about the firmware , YES , it really matters , but openwrt can keep up with netgear`s firmware with much more tools , and in this case AR7 chip RULEZZZZ .
2) I was able to use my DG834 , though i haven`t understand very much what is hapenning. The modem can sync just fine , but when i turn my desktop ON it looses sync and can not resync at all. If i plug it in a different power plug it syncs just fine. I have to find out why this is happening, any ideas ? The DG834 is on the same UPS that my PC. [btw , it is a new pc much more powerful that the old one]. The DLINK can connect with my Desktop ON with no problems ...
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The DG834 is on the same UPS that my PC. [btw , it is a new pc much more powerful that the old one]. The DLINK can connect with my Desktop ON with no problems ...
It may be the power supply to the DG834 failing. Routers can be quite sensitive to low input power and people throw them out when they just need a new power supply. The UPS may be struggling a bit more with the new PC too, try plugging DG834 striaght into a wall socket and see if that helps.
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pluging directly on the wall socket works. IS it UPS in this case ?
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Possibly the UPS not supplying enough power or struggling when the new PC is on. Guess you could maybe test that by seeing if it works in the UPS with your monitor off, for example?
What rating is your UPS i.e. what number of VA does it say? And what kind of PC and monitor have you got plugged into it? Might help us determine if it's under a high load or not.
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600VA
According to Kill a Watt Meter , my PC consumption is 162w and my LCD 19'' takes 37w = 199w total
I have plugged on the UPS
PC [162w]+ MONITOR[37] + ADSL ROUTER [3w] + WRT54G[7w] + KuroBoxPro[13w] + Printer[almost always switched off]