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oh my


Double Trouble!

Click for full size
Before the rain. Note the high return power.
Click for full size
After the rain. Note the downstream signal attenuation
Good evening. I'm using a RCA DCM425 modem. There is a 2-way splitter at the demarc, which feeds a tv (with dta) and a dc tap. The dc tap feeds a tv (with RNG150) on the lossy leg, and the cable modem on the non-lossy leg.

I am experiencing sluggish and intermittent internet connectivity due to high upstream power levels. Additionally, all our connected devices (stbs and modem) experience downstream signal attenuation when it rains. It just happened to rain here so I have proof of this. In fact, it seems the rain lowered the upstream power a bit.

I don't want to get charged for a truck roll, but I am confident that, given the rain related attenuation, the problem is on Comcast's side of the demarc. Any advice as to how to proceed?

There's sand in my tool bag
You have a problem even without the rain involved. If you move the modem directly connected to the drop, what are the levels?
Ex-Tech at the Beach.
I speak for myself, not my former employer.

I do this for a living

Dover, DE
reply to oh my
rain will not lower your upstream power.

call for a tech.
I'm better than you!

Iowa native
Springfield, MA
·Verizon Broadban..
reply to oh my
Underground or overhead drop?

If you have an underground drop, I am 99.96 percent sure that the drop went bad and it will need to be replaced. Seems like moisture causing the issue. My advice is to just schedule a truck roll.

My underground drop went bad and Comcast replaced it free of charge (even though I'm in a duplex) but they did a poor job and cut corners horribly.

oh my

Sorry about the delay in posting. The service is overhead, with taps on the poles. I would test at the demarc, but I don't have an ideal setup to do that with, plus I don't even know what to use to open the grey Cabletek box that houses the ground block. I will attempt to test though, as a cable runs around the back of our house. If this particular cable is damaged, could noise be injected in the line and trash the upstream path?

I thank y'all for the help.

Snohomish, WA
even up in the air rain will get in to the cable.

Just call for a tech, there obvisously is a problem you can't fix yourself.

oh my

I will contact Comcast soon. I have a question about billing for service calls. If I am charged, do I have to pay on the spot? Can the charge be billed to my account instead?


Colorado Springs, CO

2 edits
reply to oh my
Both the return path, i. e., upstream power level, at 54.3 dBmV and the received signal strength, i. e., download power level, at -11.5 dBmV are not very good. The high upstream level could be the cause of your problems, but both should corrected. Ideal downstream is 0.0 dBmV, but between -10 to +10 dBmV may work. The closer to 0 dBmV the better. I have had problems when upstream gets to 51 dBmV. When this happened, Comcast replaced my buried cable and all was fine. Obviously your mileage may vary

There should be no service charge if the problem is due to Comcast's hardware. If it's inside the house, they may or may not charge, depending on whether the fix is simple or your persuasive ability.
There is nothing more deceptive than an obvious fact.

Sherlock Holmes in
The Boscombe Valley Mystery
A. C. Doyle
Strand Magazine, October 1891

Bah Humbug
The Boro
·Comcast Business..
·Cingular Wireless
reply to oh my
said by oh my :

I will contact Comcast soon. I have a question about billing for service calls. If I am charged, do I have to pay on the spot? Can the charge be billed to my account instead?

My experience is that the service call is added to your bill. However, if the problem is in the drop, or in any feeder cables/connectors before it enters your residence, you should not be billed. It really depends on exactly where Comcast defines the official demarc for your connection (and that would probably be at the first spltter, or at the wall jack if there are no splitters).
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.