Is this with a WiFi connection ? If so, for a test, does a computer hardwired directly to the router / gateway device with an ethernet cable have the same problem ?
What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1
Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
What is the exact make and model number of the modem ?
The modem is an Arris SB6183. When network speeds are impacted it affects both wired and wireless hardware. A power cycle fixes it when it occurs. But it can occur several times a day.
Looks like I can't post the image?
1: - 10.0 dBmV 40.4dB
2: - 10.3 dBmV 40.3dB
3: - 10.7 dBmV 40.1dB
4: - 10.6 dBmV 40.2dB
5: - 10.4 dBmV 40.3dB
6: - 10.3 dBmV 40.3dB
7: - 10.3 dBmV 40.2dB
8: - 10.6 dBmV 40.2dB
9: - 10.0 dBmV 40.4dB
10: - 9.8 dBmV 40.4dB
11: - 10.3 dBmV 40.2dB
12: - 11.4 dBmV 39.8dB
13: - 11.6 dBmV 39.7dB
14: - 10.8 dBmV 39.8dB
15: - 11.1 dBmV 39.7dB
16: - 12.2 dBmV 39.3dB
The power levels are out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
Be advised that it may not be the splitter. It may be a bad connector / fitting / too much overall line attenuation somewhere / too many splitters. And don't use a 5-2500 splitter. Those are engineered to be used with satellite systems.
Here are some quality brand splitters that Comcast actually uses in different market areas;
Antronix CMC2002H 2-Way Splitter: http://www.amazon.com/Antronix-CMC2002H-2-Way-Splitter/dp/B001E4OH1E
Regal 2 WAY 1 GHZ Splitter: http://www.amazon.com/DIG702867-Regal-WAY-GHZ-SPLITTER/dp/B0018BQMUM/ref=sr_1_2?s=electronics&ie=UTF...
Extreme Broadband BDS102H 2-Way Digital Coax Splitter: http://www.amazon.com/EXTREME-DIGITAL-PERFORMANCE-CABLE-SPLITTER/dp/B007YV0UQW
Holland 2-way horizontal splitter 5-1000 MHz with ground.http://www.3starinc.com/holland_2-way_horizontal_splitter_5-1000_mhz-w-ground.html
Sv-2g 2-way Splitter 5-1000mhz: http://www.amazon.com/Sv-2g-2-way-Splitter-5-1000mhz-Sv2g/dp/B003TH36CK