DMT and missing tones

I am using DMT to try to find out what is wrong with my BB connection. I have noticed that on connection it shows several missing tones.

What impact does this have?

Depends on where they are as there are gaps where the AM radio stations exist. Other gaps could be down to local interferance.

The latest batch:
Gap1 1000kHz-1005kHz (Tone232)
Gap2 1108kHz-1113kHz (Tone257)
Gap3 1208kHz-1220kHz (Tone280-Tone282)
Gap4 1384kHz-1389kHz (Tone321)
Gap5 1393kHz-1397kHz (Tone323)
Gap6 1440kHz-1445kHz (Tone334)
Gap7 1458kHz-1462kHz (Tone338)
Gap8 1466kHz-1471kHz (Tone340)
Gap9 1475kHz-1484kHz (Tone342-Tone343)
Gap10 1492kHz-1501kHz (Tone346-Tone347)
Gap11 1522kHz-1527kHz (Tone353)
Gap12 1531kHz-1535kHz (Tone355)
Gap13 1540kHz-1544kHz (Tone357)
Gap14 1548kHz-1617kHz (Tone359-Tone374)
Gap15 1634kHz-1682kHz (Tone379-Tone389)
Gap16 1695kHz-1703kHz (Tone393-Tone394)
Gap17 1760kHz-1764kHz (Tone408)
Gap18 1945kHz-1949kHz (Tone451)
Gap19 2005kHz-2014kHz (Tone465-Tone466)
Gap20 2023kHz-2027kHz (Tone469)

In reply to a post by ukwiz:

The latest batch:
Gap1 1000kHz-1005kHz (Tone232) 999 KHz - Radio Solent
Gap2 1108kHz-1113kHz (Tone257) 1107 KHz Talk Sport Hampshire
Gap3 1208kHz-1220kHz (Tone280-Tone282) 1215KHz Absolute Radio (was Virgin)
Gap4 1384kHz-1389kHz (Tone321)
Gap5 1393kHz-1397kHz (Tone323)
Gap6 1440kHz-1445kHz (Tone334) 1445 KHz BBC Devon
Gap7 1458kHz-1462kHz (Tone338)
Gap8 1466kHz-1471kHz (Tone340)
Gap9 1475kHz-1484kHz (Tone342-Tone343)
Gap10 1492kHz-1501kHz (Tone346-Tone347)
Gap11 1522kHz-1527kHz (Tone353) 1521 KHz Gold, Reigate & Crawley
Gap12 1531kHz-1535kHz (Tone355)
Gap13 1540kHz-1544kHz (Tone357)
Gap14 1548kHz-1617kHz (Tone359-Tone374) 1557 Khz Gold, Southampton
Gap15 1634kHz-1682kHz (Tone379-Tone389) MW Band ends at 1605 KHz
Gap16 1695kHz-1703kHz (Tone393-Tone394)
Gap17 1760kHz-1764kHz (Tone408)
Gap18 1945kHz-1949kHz (Tone451)
Gap19 2005kHz-2014kHz (Tone465-Tone466)
Gap20 2023kHz-2027kHz (Tone469)

That's just the stations local to you (in bold)

Hi

quote :
What impact does this have?

The basic impact is that it will reduce you connection rate (synch rate ) unless you have Plenty Of SNR margin in other tones .

See the link below for a fuller explanation .
http://www.kitz.co.uk/adsl/adsl_technology.htm#frequ...

Regards Jeff

Edited by deleted (Wed 24-Jun-09 18:17:48)

In reply to a post by zebedeee:

In reply to a post by ukwiz:

The latest batch:
Gap1 1000kHz-1005kHz (Tone232) 999 KHz - Radio Solent
Gap2 1108kHz-1113kHz (Tone257) 1107 KHz Talk Sport Hampshire
Gap3 1208kHz-1220kHz (Tone280-Tone282) 1215KHz Absolute Radio (was Virgin)
Gap4 1384kHz-1389kHz (Tone321)
Gap5 1393kHz-1397kHz (Tone323)
Gap6 1440kHz-1445kHz (Tone334) 1445 KHz BBC Devon
Gap7 1458kHz-1462kHz (Tone338)
Gap8 1466kHz-1471kHz (Tone340)
Gap9 1475kHz-1484kHz (Tone342-Tone343)
Gap10 1492kHz-1501kHz (Tone346-Tone347)
Gap11 1522kHz-1527kHz (Tone353) 1521 KHz Gold, Reigate & Crawley
Gap12 1531kHz-1535kHz (Tone355)
Gap13 1540kHz-1544kHz (Tone357)
Gap14 1548kHz-1617kHz (Tone359-Tone374) 1557 Khz Gold, Southampton
Gap15 1634kHz-1682kHz (Tone379-Tone389) MW Band ends at 1605 KHz
Gap16 1695kHz-1703kHz (Tone393-Tone394)
Gap17 1760kHz-1764kHz (Tone408)
Gap18 1945kHz-1949kHz (Tone451)
Gap19 2005kHz-2014kHz (Tone465-Tone466)
Gap20 2023kHz-2027kHz (Tone469)

That's just the stations local to you (in bold)

Do you think this will improve when AM/FM radio is phased out over the next few years?

I certainly hope so as it would free up some tones on my DMT graph.

p.s. I'm assuming that my area won't get FTTC of course because, if it does, then I'm obviously going to ditch ADSL/2+ and go for that instead !

As I understand it, only national stations are to be phased out. Most of yours are local ones. All you can do is to keep your phone line as short as possible - you can't do anything to wiring on BT's side, but you can keep unfiltered extension wiring to a minimum.

If your router is connected to an extension socket, try fitting a filtered master socket, and connect your router directly to that, and run Cat5 ethernet to your PC.

Edited by deleted (Sun 28-Jun-09 12:08:37)

In reply to a post by zebedeee:

As I understand it, only national stations are to be phased out. Most of yours are local ones.

Thanks for confirming that.

In reply to a post by zebedeee:

All you can do is to keep your phone line as short as possible - you can't do anything to wiring on BT's side, but you can keep unfiltered extension wiring to a minimum.

If your router is connected to an extension socket, try fitting a filtered master socket, and connect your router directly to that, and run Cat5 ethernet to your PC.

I have an attenuation of around 55 dB and, as I don't have any extension wiring and already have a filtered faceplate fitted, my line won't improve unless my area gets FTTC.

As far as I understand it, certainly with MW is that any free frequencies will be sold / put up for auction anyway, so will still be in use by someone / something

FM frequencies are no where near hose in use for ADSL / ADSL2 / ADSL2+

Useful site to try and find out what frquencies correspond to what stations:

http://transmit.tv

These are just some of mine
http://transmit.tv/main.php?t=161792295
http://transmit.tv/main.php?t=30671290
http://transmit.tv/main.php?s=241471856&x=555264&y=1...
http://transmit.tv/main.php?t=577666538

Thanks for the link, it's an interesting site.