Comcast Service Quality Checklist
Comcast internet and voice service is an excellent value. Yet, the Comcast network and outside plant requires vendor inspection and monitoring to maintain a satisfactory level of service. Follow this checklist to optimize your Comcast service.
The coax cabling must be perfect
- The cable modem must be installed next to your router in your computer area/room and on a UPS.
- The cable drop from the mainline to your modem must be RG6 cable.
- Remove old HBO filters from the tap plate used in the days of an analog cable TV.
- Replace the splitter between outside cable and cable modem with a quality two-way splitter (as pictured) with a favored power port for the cable modem.
- If you have two modems, they must have separate connections to the main line tap plate. They can not both exists on the same RG6 coax building drop.
- Extremely cold days can cause "cable suck-out" which causes the cable center conductor to "suck out of it's connector. Google "suck-out" for details.
- We discourage sharing of cable with TV or cable dialtone boxes as this is a point for noise and power loss.
- Fix the temp mainline splitter installed when your neighbor got Comcast and the 3rd party installer split your tap and cut your signal in half.
We require business grade Internet service
- SMC D3G cable modem is required as it has faster electronics than the 8014 and thus allows for higher speeds.
- Business grade service has a higher level of response and technical support.
- Business grade service allows a static IP. Static IP allows us to monitor your service.
- If sharing the Comcast with any data, choose one up from the base package.
Verify signal levels: Downstream power is 0db or higher. Signal to noise (SNR) is 32db or Higher
Comcast service delivery is like municipal water service delivery. It's a system of interconnected large and small diameter pipes. Comcast states that a working "water pressure" range is -15db to +15db with lower than -11db as being in the "yellow range". Unofficially, Comcast insiders state it should be at 0db or higher for trouble free performance. The picture below shows a Comcast SMC8014 cable modem diagnostic page with very low downstream power but acceptable (SNR) signal to noise ratio.
Good SNR is especially important if the downstream power can not be improved. Inside cabling defects such as a loose connection to a TV can cause poor SNR. this. On critical or new cable modem installs, we will discourage connection of cable TV until performance is proven. It is the customer's responsibility to correct any deficiencies on interior cabling.
Above modem performance must be within normal bounds for a week according to Comcast Scout or Grandslam systems.
Ground the cable shield OUTSIDE the building entrance per National Electrical Code section 800-33
- Cable Grounding. The metallic sheath of communications cables entering buildings shall be grounded as close as practicable to the point of entrance or shall be interrupted as close to the point of entrance as practicable by an insulating joint or equivalent device.
- The grounding conductor shall not be smaller than No. 14. The grounding conductor shall be run to the grounding electrode in as straight a line as practicable.
- Bonding of Electrodes. A bonding jumper not smaller than No. 6 copper or equivalent shall be connected between the communications grounding electrode and power grounding electrode system at the building or structure served where separate electrodes are used. Bonding together of all separate electrodes shall be permitted.
Modem performance issues
- Comcast modems share frequencies on the coax mainline with their neighbors before the signals are aggregated to neighborhood coax-to-fiber hub. At times, modems may shift to less congested frequencies. This switch should happen within 50 ms but in an abnormal condition, this switch can take up to a minute. During that time, no data is transmitted. Any VPN's will drop. Consider replacing the modem.
- Go to firewall settings and disable "Gateway Smart Packet Detection".
Dial tone issues we have seen
- Check your Caller ID name at www.fixcallerid.com
- Faxing failure rates may increase vs. a standard POTS line. Comcast has published incompatibilities with fax machines.
- If you have an internal voice mail system, have your tech check your loss of loop settings to insure your voicemail system will hang-up when the caller hangs up.
Slip your installer a $20 bill and help with the install
Comcast independent contractors work on a per job basis. They want to leave as soon as possible and financially are forced to do the job quickly.
