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Upstream QAM modulation

One of my upstream channels is constantly fluctuating between 16 32 and 64 QAM, I’ve had an engineer out and he couldn’t find a problem, he checked my connection in the house and at the cabinet, he also replaced my hub, but this hasn’t solved the problem, the power levels are all around 45db and seem stable,

could it be a more central problem?

any ideas or suggestions?

thanks

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Re: Upstream QAM modulation

A lot depend on if your service is being impacted. You do not say exactly in your post.


Tudor
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Re: Upstream QAM modulation

Any number of factors can cause noise on upstream channels. Faulty amps & non-standard DIY customer wiring to name a few. You cannot see the upstream SNR on VM Hubs (although VM techs can). When I had this problem earlier this year it took several weeks for VM to find the culprit.

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Re: Upstream QAM modulation

Interesting think I have the same issue although only have 16qam showing on one channel am waiting to try and arrange an engineer.

I cannot upload at more than 3mb when single stream selected.. What was your issue mine has been destroying my upload for months.

Upstream bonded channels

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

1394000003.25512064 qam68
2258000443.275512016 qam70
3326000003.25512064 qam69
4462000003.25512064 qam67
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Re: Upstream QAM modulation

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Re: Upstream QAM modulation

Same just one channel on 16 qam, rest stay on 64, 

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Re: Upstream QAM modulation

@nodrogd

I would be interested to know how it was sorted..

cause I have been in this situation for weeks. has to be something wrong somewhere,

 

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Re: Upstream QAM modulation

I’ve had an engineer, he said nothing is wrong

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Re: Upstream QAM modulation

what effect is having on speed?

 

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Re: Upstream QAM modulation

full recovery this afternoon watched it go from 32qam to 64qam...

as soon as it went to 32qam upload was straight back to 37mb upload..

no idea but just hope it says have had nearly a month of 3-4mb..

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