ST546v5: again, some odd results

I'm still getting some truly odd results with my ST546v5 (in combination with DMT) and am wondering if anyone can throw some light on the matter.

First, my SNR has deviated today by an enormous amount. Since tweaking a couple of days ago with DMT and getting the line set at 4M bps, SNR 11.5dB, the SNR has dropped by only about 2dB in that time (interleaving is on) ........................ except for this evening, when it dropped to 1.5dB. Surely, this is nonsense? The line would need to be subjected to some considerable interference for the SNR to suddenly drop by that much. My line's never deviated before to anything like that extent. FEC errors are currently around 37 million (2 days worth).

Some other strange thing I've noticed in the router's control panel is that the gateway address is showing as 217.X.X.X. Surely, this should be instead 192.168.1.254? These are what are found at Broadband Connection/Internet/TCP-IP Settings.

I'm running with DHCP on. Given that there's only machine attached, is there any merit in having the router's DHCP server on and so allotting different addresses periodically? Would it be any less secure by turning DHCP off and having the router alot only a fixed address?

check http://bbs.adslguide.org.uk/showflat.php?Cat=&Board=general&Number=2657528&page=0&view=collapsed&sb=5&o=0&fpart= the same thing started happening to me since couple of nights ago it may be something else.

The routers gateway wont be 192.168.1.254 it will be a external ip, that ip is the gateway for your computers assuming they using NAT.

Since you appear to be having problems why not get 5.4.0.14 on so if it happens again you have the dmt graph to see exactly whats going on, which frequencies etc. For instance I have all these gaps, only 5 in the day.

Gap1 276kHz-280kHz (Tone64) Pilot
Gap2 694kHz-699kHz (Tone161)
Gap3 712kHz-716kHz (Tone165)
Gap4 802kHz-806kHz (Tone186)
Gap5 811kHz-897kHz (Tone188-Tone207)
Gap6 901kHz-914kHz (Tone209-Tone211)
Gap7 919kHz-923kHz (Tone213)
Gap8 927kHz-932kHz (Tone215)
Gap9 936kHz-940kHz (Tone217)
Gap10 944kHz-949kHz (Tone219)
Gap11 953kHz-957kHz (Tone221)
Gap12 962kHz-1009kHz (Tone223-Tone233)
Gap13 1018kHz-1022kHz (Tone236)
Gap14 1026kHz-1031kHz (Tone238)
Gap15 1035kHz-1039kHz (Tone240)

Edited by Chrysalis (Tue 12-Sep-06 01:19:03)

Yes, I would agree. You need the spectrum map. You should then be able to see whether the interference is from a narrow source (like an AM radio station) or from more wideband interference like an electric motor in a treadmill.

I don't know where you live but in Dorset we had a fairly horrible thunderstorm yesterday evening and my snr fluctuated from 10.5 down to 1.5 but still remained in synch until we had a power cut.

Mine's the Outer London area. No, we didn't have any thunderstorm yesterday, so it couldn't have been caused by that. Curiously, today it's gone back to 11.5dB (same speed). I've now tweaked it again and done a reboot/resync.

Chrysalis,

You say that "the router's gateway won't be 192.168.1.254, it will be ....................using NAT". Did you REALLY mean that that 127.X.X.X address that I saw was EXTERNAL to my system? In other words, that it was an address on the WAN side of things, eg. at my ISP? (That address certainly isn't one of my ISP's DNS addresses). What's the correct term to use for the address 192.168.1.254? I thought it was 'gateway address'.

a gateway is where the device has to goto for its data ie .like its parent. Your router's gateway will be located external if the routers gateway was 192.168.1.254 it would be connecting to itself

I had a look in my gui now to see what my gateway is but I cant see it visible, I also cant remember setting it I just entered the username and password and that probably routes it all itself.

I think we are misunderstanding each other here, when you say router's gateway you mean a gateway listed on your pc or the router itself? if the router what is it set to now?

I found this on the home network page now.

DHCP Pools
DHCP Pool Name Address Range Gateway
LAN_private 192.168.1.64 - 192.168.1.253 192.168.1.254

The gateway listed their means the gateway of the LAN itself which is the router itself.

Edited by Chrysalis (Tue 12-Sep-06 15:39:44)

I think his wasnt thunderstorm behaviour but more like what I been seeing, it slowly moving down till it settles on a lower figure, during a thunderstorm the snr instantly dissapears and is something completely different.

Your original post said 217.X.X.X
If it was actually 127.0.0.1, I think that is the default IP address for your PC (any PC)
so it was probably not getting an IP address under DHCP from your router at the time.

If I'm not mistaken, "IP Address", in Internet/Connection Information, is the user's Internet IP address. Some users will be using a dynamic IP address, some will be using a static address.

Remember, this is as listed in the router's control panel, not anywhere on the PC or LAN. And it's with reference to firmware 6.1.4.7. Earlier firmware might not show the address in quite the same way, or at all.