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[burakkucat]

    Hmm . . . Not too easy to compare as the scaling on the x-axis is different. 

However to this sleepy cat's eye, there appears to be some improvement at the higher frequencies. 

[Semmy]

Unfortunately due to the attenuation at my line length, those frequencies are not active 

[NewtronStar]

The RF3 tried to cut out a lot of noise but allows the DSL frequencies through. (the rf2 filter is similar or identical to the one on the bell wire on the newer filtered face plates so filtering out the bell wire noise greatly just as 2 of them, one on each leg does in an RF2)

So lets try and come up with an RFI filter at 7.206 to 7.464 Mhz that effects the masses on VDSL2 can it be done ? no it can't if you try to subdue the frequencies by the filtering method there is always going to a negative effect at the receiving end, so if you have RFI on broadband then there is nothing we can do about it and I don't even think BT Openreach can fix it, it's all down to the Laws of Physics and that can't be changed by no man 

[NewtronStar]

Unfortunately due to the attenuation at my line length, those frequencies are not active 

and also the two QLN are of different times one is going into RFI peak time and the other is coming out of RFI peak time, though RFI peak times are dependant on where you live (North and South in the UK.

[Semmy]

On an allied note there appears to have been a slight drop in the number of FEC errors and the number of bitswaps.
Maybe it will earn me a reduction in interleaving level (currently 1065/90)?

As noted earlier I will let it rest a while and see what happens DLM wise.

[NewtronStar]

On an allied note there appears to have been a slight drop in the number of FEC errors and the number of bitswaps.
Maybe it will earn me a reduction in interleaving level (currently 1065/90)?

As noted earlier I will let it rest a while and see what happens DLM wise.

yes please monitor your line over a few weeks and let us RF3 owners know if it's worth installing.

Thanks Semmy

[burakkucat]

An RF3 is not really a filter . . . as in tuned to a specific spot frequency or a band of frequencies. It is a pair of chokes, wound on a common former, which act by blocking any common mode signal whilst allowing the differential mode signal to pass.

Remember that an xDSL circuit operates in differential mode. So to minimise the effect of common mode RFI, the two legs of the circuit should be balanced. The better the balance, the less the effect of RFI upon it.

JGO has provided a good description of an RF3's mode of operation. 

[burakkucat]

Unfortunately due to the attenuation at my line length, those frequencies are not active 

Do you have the raw, tabular, data from which those two graphs were produced? If yes, then I would be able to produce the two graphs with identical x-axes which would allow simple comparison, by eye.

[NewtronStar]

An RF3 is not really a filter . . . as in tuned to a specific spot frequency or a band of frequencies. It is a pair of chokes, wound on a common former, which act by blocking any common mode signal whilst allowing the differential mode signal to pass.

Remember that an xDSL circuit operates in differential mode. So to minimise the effect of common mode RFI, the two legs of the circuit should be balanced. The better the balance, the less the effect of RFI upon it.

JGO has provided a good description of an RF3's mode of operation. 

yes I read it a few times BC and it does look like it's tuned for the lower frequencys of ADSL my RFI is coming in at the higher frequencys.

if JGO could investigate which specific spot frequency or a band of frequencies the RF3 is targeting then it would be helpful to see the specification 

[Semmy]

One last final question before I hit the sack.

What level of noise is acceptable on a quiet Iine test?
Mine has what I can only describe as a faint hiss/white noise, audible but not loud enough to interfere with voice traffic.

[burakkucat]

. . . specific spot frequency or a band of frequencies the RF3 is targeting . . .

   It isn't. It doesn't. It blocks common mode signals (as best as it can) from baseband (0 Hz) to the upper frequencies used by xDSL whilst allowing differential mode signals to pass.

[burakkucat]

What level of noise is acceptable on a quiet Iine test?

How long is a piece of string? 

Mine has what I can only describe as a faint hiss/white noise, audible but not loud enough to interfere with voice traffic.

That might be the beginnings of a HR joint. The only way I can describe what one should hear when performing a QLT is to say that it should be obvious that the circuit is electrically active -- that it has a "presence".

[NewtronStar]

. . . specific spot frequency or a band of frequencies the RF3 is targeting . . .

 

Don't do that BC you'll get a sore head, feck it I'll just install it and get it over and done with 

[Semmy]

Do you have the raw, tabular, data from which those two graphs were produced? If yes, then I would be able to produce the two graphs with identical x-axes which would allow simple comparison, by eye.

Will have a look this evening after work. Alternatively what would you recommend as a useful graphing/plotting package? (ideally freeware!)

[burakkucat]

Will have a look this evening after work. Alternatively what would you recommend as a useful graphing/plotting package? (ideally freeware!)

The simplest way, of course, is just to configure the x-axis in DSLstats appropriately and leave it set. Don't swap it about, then you will have consistent plots!

For the plotting of graphs, I make use of GNUplot.