Slow upload speed on fttc

Living in a rural location about 5.5km from the exchange we were getting about 1.5 Mb/s down (on a good day) and 0.3 Mb/s up on ADSL which is about what I expected. Two weeks ago we were connected to fttc, the cabinet being about 1.8km away and I am very happy with the download speed of 17 Mb/s but I am rather disappointed in the upload speed which is only 1.2 Mb/s. My ISP (Zen) has carried out a series of line tests and found no fault and is at a loss to explain the situation except that they say that upload speed degrades faster with distance from the cabinet than ADSL does due to the higher frequencies used - has anyone else any experience of this?

Yes, it is true - to a certain extent.

Working from the lowest frequency end thee is a small upstream band, U0, which uses tones up to 32, then Downstream, D1, followed bu U1, D2, U2, D3. Whereas on ADSL all of the upstream is at the low frequency end. So, yes it appears to degrade faster because of the higher frequencies in use.

If you can run DSL Stats the graphs available will show what is happening.

Yes I see this too. Download is 0.625 of the max 80, whereas upload is 0.4 of the max 20.
Speeds are in line with what the BT checker reports (http://www.dslchecker.bt.com/adsl/ADSLChecker.TelephoneNumberOutput)

My speeds are nowhere near what dsl checker reports for my telephone number:

Telephone Number xxxxxxxxxxx on Exchange FOLKINGHAM is served by Cabinet 1

High Low High Low
FTTC Range A (Clean) 55.3 35.7 13.9 8.3 -- Available
FTTC Range B (Impacted) 46.5 27.4 13.7 6.1 -- Available

My neighbours (same distance from the cabinet) are being connected today so it will be interesting to see what they get

The figures given by the BT checker do change. Originally they predicted a much higher speed for me (which I didn't get). Now they are more inline, I have no idea why...

BT were pressured by the ASA to make their estimates more closely reflect actual speeds.

There are times when the checker database may think a phone number is in another location, what does the checker estimate for the actual house number and postcode.

55 Mbps is NOT achievable at 1.8km from a cabinet

If I try the house name and postcode I get:

Your address has been successfully matched; however we cannot determine ADSL availability at this address. Please try the Telephone Number or Postcode Checker.

Tha actual postcode location is 900m away from our property (there's only 2 properties here so I assume they didn't think it worth giving us our own postcode) so I wouldn't accept what it predicted anyway but if I try that in dsl checker I get:

WBC ADSL 2+ Up to 2 -- 1 to 3.5 Available
ADSL Max Up to 1.5 -- 1 to 2.5 Available

Which is patently wrong because everybody else on that postcode can get FTTC (it's about 900m from the cabinet). Yes, I'm aware that the download estimates were wrong but I though I could get a better upload than 1.3 Mb/s

hmm, that figures...

Okay so one of those where the checker is in a mess basically.

You can do the get mad and complain but nothing will actually improve for your broadband as a result of that. best that can be managed is to get things updated.

Fortunately postcodes that are this large are pretty rare (much more common in Northern Ireland I find)