Since moving into my home, I’ve had my cable modem in our office. A room above our garage that has coax run to it from the garage, which is where the CATV coax enters the house. Coax enters the house through a wall, goes into a splitter, and heads from there up to our office. Total run length from the splitter is about 30ft. With the modem in the office, and then in the garage, the data for the modem follows (Update 5/26/11: After a couple days, the signal levels changed a bit in its new location. I’ve found online that 6 dBmV is actually a bit on the high side for signal strength, but within acceptable limits):
| Office | Garage | Garage 2 | |
|---|---|---|---|
| Downstream Freq | 567.00 mhz | 567.00 mhz | 579.00 mhz |
| Downstream Power | 3 dBmV | 4 dBmV | 6 dBmV |
| Downstream SNR | 36 dB | 36 dB | 35 dB |
| Modulation | QAM256 | QAM256 | QAM256 |
| Upstream Freq | 32.400 mhz | 32.400 mhz | 22.800 |
| Upstream Power | 44 dBmV | 43 dBmV | 42 dBmV |
| Channel Type | DOCSIS 2.0 (ATDMA) | DOCSIS 2.0 (ATDMA) | DOCSIS 2.0 (ATDMA) |
| Symbol Rate | 5120 kSym/sec | 5120 kSym/sec | 5120 kSym/sec |
| Modulation | QAM64 | QAM64 | QAM64 |
It is interesting to note that moving the modem resulted in very little change. This certainly says something about the quality of coax I used to the office, as well as the crimps/connections. What I hope is that the change in location will help with the occasional blip I see where my modem will drop down to DOCSIS 1.0 on the upstream side (though this could also be due to something on Comcast’s end, as my transmit power never goes above 44dBmV).
As the real plus, getting the cable modem out of the office is a nice change. My hope eventually is to relocate all the server stuff down to the garage. The picture shows that I’ve mounted the cable modem with zip ties onto pegboard. The pegboard is held to 2×4’s with some bolts, and wing-nuts. The power outlet I installed by cutting the flex conduit that ran to the compressor outlet, and installing a new electrical box. The compressor outlet was on it’s own 20A circuit, so adding the cable modem shouldn’t hamper that at all. If I do eventually move everything down to the garage, I should still be okay, since the compressor doesn’t draw over 15A, and the server, disk array, and modem don’t draw anywhere near 5A. I would, however, need to keep the wireless base station in the main part of the house… which would mean using the server, or something else, as a router. This is at least a year away though, as I want to install a full on patch panel above the cable modem for coax and Cat5e.
That’s all for now. I wouldn’t recommend doing this unless you really want to move the modem, or you’ve got a LOT of coax/splitters between the modem and your ingress point.
