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Forum Discussion
CAX30 Drops Internet Connection
CAX30 modem/router with firmware 2.2.2.2 My CAX30 had been solid for about the past 2 1/2 months after a tech came out to install a splitter to reduce power levels. Before installing the splitter...
Something the ISP needs to look at.
The tech came but said that the voltages on the line were within their specs (+12 dBmV to -10 dBmV) even though they are not within the specs of the CAX30 that Optimum's website says it compatible and most other modems. All Optimum's website says is that any DOCSIS 3.1 modem is compatible. Also, he really didn't know what the error messages that the CAX30 was reporting meant.
After doing some more research, I found a 6 dB attenuator on Amazon that will reduce downstream voltages while not affecting upstream voltages. The reason that's important is that when a regular 3 dB or 6 dB attenuator or cable splitter is attached, downstream voltages are reduced, but upstream voltages increase. This caused a different error, one related to upstream voltages, to be reported when the Internet connection went down. With this different attenuator, downstream voltages are between 2.2 dBmV and 3.4 dBmv. The upstream voltages remain at 45.8 dBmV to 46.3 dBmV. Both are within specs for the CAX 30.
The device is a PPC FPA6-54 Forward Path Attenuator 6dB 75 Ohms for DOCSIS Cable TV Box and Modem. In the product description it says that "PPC’s forward path attenuators provide a fixed level of attenuation within the downstream frequencies without affecting upstream frequencies." I had it on hand when the tech arrived. He had no idea that such a device existed.
There may be some issues with using this forward path attenuator if your cable company uses upstream channels that overlap downstream channels. This device assumes that all upstream channels are 42 MHz and below. To meet the needs of faster speeds, some newer cable systems are using upstream frequencies in the 85 MHz and 108 MHz ranges. This device will also reduce power to those upstream frequencies if your cable system uses them. For me, this is not an issue as all upstream frequencies are sub 42MHz.
I'm going to wait a week or so before marking this thread as solved to make sure that the connection is really stable.
Power levels should follow that NG puts forth for there modems:
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
Looks like you found something that got the power with in those specs.
Come back and let us know if it works fully after a few days.
I've been monitoring upstream and downstream power levels after installing the downstream attenuator and they've remained within specs. I was hoping to get a solid week of use before marking this solved. Unfortunately, we had a power outage after 5 days and then Optimum had an unplanned outage today after 4 days of uptime. Each time I've rebooted the router, I get a Dynamic Range Window Violation warning, but that doesn't seem to affect the connection.
I did notice that the cable firmware version is 1.04.09 while Netgear has released 1.04.10. This might also be the source of this warning. Unfortunately, Optimum has to update the firmware and I'm not sure how far I would get trying to have them do the update despite the fact that Netgear claims to provide firmware updates to providers.
So rather than drag this out, I guess installing the downstream attentuator fixed the problem and I will mark this as solved (maybe).
Something to contact the ISP about to see if they can update the modem side FW if they have approved of the modem side FW.
Router side FW, NG has this for users to update too: