Constant flashing amber link light on Cisco DPC3008

[Llamallamanson]

I recently began service with xfinity and I am renting the Cisco DPC3008 modem directly from Comcast. The modem is connected to a Cisco Linksys E1200 wireless router. The link light has been flashing yellow since I hooked the cable up (~4 days) and the connection is horrible. Pingtest has been giving me consistent "D" grades with 128 ms ping, 119 ms jitter and ~7% packet loss. 

I have tried the following things to no avail:

• Unplugged the router and modem individually and jointly, allowing several minutes without energy. 
• Reset both the modem and the wireless router
• Switched channels on the wireless router
• Checked the coax cables to make sure they are plugged in securely 

Other potentially relevant facts: cable is connected using a splitter that is also hooked up to the cable box. I am using the spliter I recieved from Comcast, is it possible this is the problem? 

I am open to any suggestions. I want to exhaust all possible options before buying a modem or replacing my wireless router. 

Thank you for the help. 

[EG]

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

[Llamallamanson]

Hope this is what you're looking for. Thanks again!

Downstream:

Channel 1: 13.7 dBmV              39.9 dB

Channel 2: 15.1 dBmV              40.1 dB

Channel 3: 16.0 dBmV              40.3 dB

Channel 4: 16.4 dBmV              40.4 dB

Channel 5: 16.5 dBmV              40.8 dB

Channel 6: 16.6 dBmV              40.8 dB

Channel 7: 16.7 dBmV              40.9 dB

Channel 8: 16.1 dBmV              40.6 dB

Upstream:

Channel 1:     41.0 dBmV

Channel 2:     40.5 dBmV

Channel 3:     39.3 dBmV

Channel 4:     0.0 dBmV

[Nerdburg]

Your signal is "hot" meaning you have too much downstream signal strength. I assume you don't have an amplifier installed? If you do, remove it. If you don't have an amp, you should call Comcast to come out and adjust the levels.

[bryanu · Accepted solution]

I got same modem and have hot signals also, though odly on the rented UBEE it read my DS as 10.5 and when I got the cisco it was 13-14ish..

I have replaced my modem again with another new Cisco as last one got hit from surge over Comcast line (thanks comcast!)

New modem shows even hotter signals... I question how accurate the cisco is on the signal levels.

Anyway, the blinking amber light on link means the link between the modem and router is 100Mbps is all.

The light will always blink also btw, is normal for cable modems. If you link to a gig port it will/should turn green, if not, defective modem.

that should't be the cause for your troubles, but those power levels will.

IF you do not have an amp on your line, try tossing a splitter on it to help reduce signal. Your US and DS are both a bit hot, though in honesty if those are true accurate readings you might need a few splitters lol.

If the house has no amp time to call comcast, they need to balance your ped better. It may be an amped ped on manual and not automatic.

[EG]

One must be cognizant of how much additional attenuation to insert as this may push one's upstream power level out of spec and recreate the very problem they are trying to fix. Also, real attenuators are preferred over splitters. If there are unused ports on a splitter these can be source of noise ingress and RF egress. Unused ports should be capped with terminators.