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16 qam causing slow uploads

My upload speed has been slower than it should be in the last week or so, and I checked my modem and the upstream shows 16 qam, it used to be 64 qam.

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

1393999334.1512016 qam2
2257993124.05512016 qam4
3462006984.15512016 qam1
4325999424.075512016 qam3


I have rebooted the hub a couple of times but it comes back at 16 qam everytime.  I'm running the hub in modem mode.

Upload speeds are around 15mbit, I'm on the 350mbit down / 30mbit up package, so I'm only getting around half my upload speed.

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Very Insightful Person
Very Insightful Person
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Re: 16 qam causing slow uploads

You are right it should be 64. Can you provide more data. Post up both tables from the Downstream and the Upstream as well - also the network logs.

Then, if you haven’t already, set up a free “Broadband Quality Monitor” to continually monitor the state of your connection and record any true network dropouts - it will thus allow you to differentiate between those and simple wifi dropouts. It does it 24/7/365 and it keeps a visual record of any/all of your network disconnections, useful data to have to match to the Network logs (in your Hub settings) and also in discussions with VM - note it will take a few hours to start seeing a sensible picture - post up the “link” (as per instructions on the TB website) when you have the first 24h period.


I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
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