12-18-2022 08:50 PM - edited 12-18-2022 08:53 PM
Hi all,
TL;DR - my OFDM levels and correctable codewords seem high. Would removing the amp + splitter put the OFDM levels more in range even if it may cause QAM levels to suffer?
The cable that enters my home through the electrical box in the basement is connected to amplifier (Antronix MVRA501B). The amp was installed by Rogers during my pre-Ignite days where I had 4 cable runs throughout the home. When I switched to Ignite, the install tech didn't check any part of that so the amp is still part of the setup. I ended up disconnecting 3 of 4 lines from the amp and put terminal caps on the unused outputs on the amp.
The one active cable from the amp goes up to the 2nd floor where the XB7 is. As the signal was too strong the tech installed a splitter (-3dB) before the modem.
I've always had that QAM high frequency roll-off so I thought I needed the amp but I see my OFDM levels seem high. I also see that I have a high number of Correctable Codewords for my OFDM channels. Is this a problem?
I think I read somewhere if you have OFDM, then it's more important to keep those happy vs the QAM channels. Is the range for OFDM like QAM (+-10dBmV and around 38dB)?
Should I remove the amp & -3dB splitter and would that improve my situation? I don't have any critical issues aside from only getting 80% of advertised speeds (400Mbps on a 500Mbps plan). If I remove the amp, I think it may cause some of the high freq QAM channels to go beyond -10dBs so I'm not sure if I should. Back when I had the CODA, I was getting similar if not slightly higher speeds on a 300Mbps plan).
Any advice would be appreciated. Thanks.
Downstream | Channel Bonding Value | ||||||||||||||||||||||||||||||||||
Index | 13 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 34 | 33 | 34 |
Lock Status | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked | Locked |
Frequency | 651 MHz | 279 MHz | 579 MHz | 585 MHz | 591 MHz | 597 MHz | 603 MHz | 609 MHz | 615 MHz | 621 MHz | 633 MHz | 639 MHz | 645 MHz | 657 MHz | 663 MHz | 669 MHz | 675 MHz | 681 MHz | 687 MHz | 693 MHz | 699 MHz | 705 MHz | 711 MHz | 717 MHz | 723 MHz | 825 MHz | 831 MHz | 837 MHz | 843 MHz | 849 MHz | 855 MHz | 861 MHz | 216 MHz | 350000000 | 216000000 |
SNR | 37.6 dB | 39.2 dB | 40.6 dB | 40.6 dB | 39.8 dB | 39.6 dB | 39.8 dB | 39.1 dB | 38.4 dB | 38.8 dB | 38.6 dB | 38.7 dB | 38.3 dB | 38.0 dB | 38.1 dB | 37.8 dB | 36.6 dB | 38.0 dB | 37.4 dB | 37.2 dB | 36.8 dB | 36.1 dB | 35.9 dB | 35.9 dB | 36.4 dB | 36.5 dB | 36.6 dB | 36.7 dB | 36.8 dB | 37.2 dB | 37.3 dB | 37.4 dB | 42.8 dB | 40.9 dB | 42.7 dB |
Power Level | -3.0 dBmV | 4.4 dBmV | 1.5 dBmV | 1.3 dBmV | 1.3 dBmV | 1.1 dBmV | 0.5 dBmV | 0.1 dBmV | 0.7 dBmV | 0.8 dBmV | -1.5 dBmV | -1.8 dBmV | -2.3 dBmV | -3.0 dBmV | -3.1 dBmV | -3.1 dBmV | -3.1 dBmV | -3.3 dBmV | -3.8 dBmV | -4.4 dBmV | -5.0 dBmV | -5.7 dBmV | -6.1 dBmV | -6.1 dBmV | -5.4 dBmV | -5.1 dBmV | -5.1 dBmV | -5.0 dBmV | -4.6 dBmV | -4.6 dBmV | -4.4 dBmV | -4.5 dBmV | 9.3 dBmV | 5.5 dBmV | 9.2 dBmV |
Modulation | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | 256 QAM | OFDM | OFDM | OFDM |
Upstream | Channel Bonding Value | |||
Index | 1 | 2 | 3 | 4 |
Lock Status | Locked | Locked | Locked | Locked |
Frequency | 21 MHz | 25 MHz | 32 MHz | 38 MHz |
Symbol Rate | 2560 | 5120 | 5120 | 5120 |
Power Level | 36.8 dBmV | 39.0 dBmV | 41.0 dBmV | 41.0 dBmV |
Modulation | QAM | QAM | QAM | QAM |
Channel Type | TDMA_AND_ATDMA | ATDMA | ATDMA | ATDMA |
CM Error Codewords | ||||||||||||||||||||||||||||||||||
Index | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 |
Unerrored Codewords | 3427353530 | 4276686330 | 4276698476 | 4276725936 | 4276755056 | 4276770164 | 4276783570 | 4276810139 | 4276820842 | 4276825259 | 4276845268 | 4276849272 | 4276852299 | 4276854167 | 4276865294 | 4276869339 | 4276882412 | 4276898483 | 4276907401 | 4276913074 | 4276929965 | 4276936737 | 4230822981 | 4276952588 | 4276956256 | 4276961790 | 4276974188 | 4276974622 | 4276989424 | 4276991390 | 4276996022 | 4276994728 | 2737725724 | 3427353530 |
Correctable Codewords | 251038570 | 0 | 3 | 0 | 1 | 2 | 0 | 0 | 2 | 0 | 0 | 1 | 3 | 4 | 2 | 5 | 4 | 10 | 13 | 43 | 110 | 296 | 599 | 653 | 360 | 235 | 177 | 164 | 93 | 79 | 42 | 43 | 2330990283 | 251038570 |
Uncorrectable Codewords | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 92 | 237 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
12-18-2022 11:43 PM - edited 12-18-2022 11:45 PM
@Hwaiting wrote:
Hi all,
TL;DR - my OFDM levels and correctable codewords seem high. Would removing the amp + splitter put the OFDM levels more in range even if it may cause QAM levels to suffer?
Having a high number of correctable errors on an OFDM channel is not a problem. It's actually a good thing. (See this topic for more info.) The important thing is that you have zero (or close to zero) uncorrectable errors.
The cable that enters my home through the electrical box in the basement is connected to amplifier (Antronix MVRA501B). The amp was installed by Rogers during my pre-Ignite days where I had 4 cable runs throughout the home. When I switched to Ignite, the install tech didn't check any part of that so the amp is still part of the setup. I ended up disconnecting 3 of 4 lines from the amp and put terminal caps on the unused outputs on the amp.
I would remove the amp. It's probably a "zero gain" amp (0 dB gain on the output) and these are typically used where the signal coming into the home is good but a passive splitter would cause the output to drop to unacceptable levels. With a "zero gain" amplifier/splitter, the output signal should be at the same level as the input signal... so there is no benefit to leaving it installed if you only have one coax-connected device in your home. Also, while the signal will not get boosted, noise will... and that is not good.
Remove the amplifier/splitter and use an F81 barrel connect to connect the incoming coax feed to the coax line leading to your gateway. Alternatively, you can use the splitter that the tech installed as well.
I'm not sure what to make of your signals. Your OFDM channels are reading 9 dBmV but you have other QAM channels reading -6 dBmV. Will be interesting to see if things level out after removing the amplifier.