Digital Cable Trouble

So I got digital cable (by Comcast) this past weekend. I picked up the converter boxes myself (I hate having people come to my house) and hooked them up. It seemed to be working fine, but I’ve noticed that several channels I’m supposed to get aren’t coming in. For example, MTV2. It just shows a “This channel will be available momentarily” message. I called Comcast to see what’s up, and they said something about signal strength and that they needed to schedule a repair. There’s no way I’m giving in that easily :wink:

I have 5 cable outlets in my house. One is for the cable modem, and the others have TVs. Before I got digital cable, the analog cable was fuzzy on the lower channels. When I got broadband, the cable guy installed an amplifier where the cable first comes in to my house. After that, the lower channels became clear, but now they’re fuzzy again (about a year later). Is it possible that the amplifier has gone bad? My broadband still works without a problem.

My question is, can I buy and install a better amplifier, and is it likely that it will solve the problem? I’m pretty sure that it has to be a special kind as to not block the return signal needed for digital cable and broadband. I should also mention that the cable line is split once immediately after the amplifier (a standard-looking Radio-Shack one-to-two cable splitter), and I don’t know how it’s split to the individual jacks (the splits are somewhere in the walls).



Don’t buy anything, let the cable company come and do it for free. It sounds like it does just need to be amped up a bit, but they’ll test it and make sure that is actually the problem before they do anything though. Could be a bad connection somewhere in the house too.

I had the same trouble (this channel will be availble shortly) with my digital cable. They had to come out to the house and replace the cable across the street from my house. They tried to explain it to me, but I’m pretty stupid so I may have this wrong. It’s something about the digital receiver being much more sensitive, so that a weak signal simply won’t come in at all, instead of badly. Oh hell, I do sound dumb.

Anyway, the repair fixed the problem. Go ahead and give in easily, I know it’s rare but sometimes big companys actually are ok.

Well the only problem is that due to the nature of my job it’s nearly impossible for me to be available during the hours they work…I really don’t mind paying for an amp, so I think I’m going to try one like this: CVT-38BID

I did some research on my own and it seems like the problems I’m having are related to signal strength loss. I guess that the amp I have now isn’t strong enough.

Related question: Does stringing two amps in a row add the amplification?



I’ll second the suggestion to have Comcast come out and fix the problem. I also had reception issues that were fixed by replacing a cable on the box outside my apartment. The tech who arrives will have the training and equipment to determine the cause. The only problem I had with a service call was arranging a time when I would be at home.

Exactly my problem. It will take a long time before I can arrange to be at home for a repair.

I’m going to try the amplifier first because I can return it if it doesn’t fix the problem. Do you think it’s possible that Comcast would come check the wires outside of the house without needing me to be home?

Wish me luck! I should get the amp tomorrow if FedEx ground delivers from NY to NJ overnight as usual. I’ll post the results FYI.

Thanks for your advice, everyone!


In my case, the tech first needed to test the strength of the signal from the wall to the cable box before he was able to determine that the cable outside the apartment (at the junction box) needed to be replaced.

Nope. Not in the outside plant anyway. In those amps there’s a pre-amp stage where the incoming signal is “padded down” to whatever minimum level the amplifier is designed to handle. The one you linked to appears to be constructed the same way; the product datasheet (pdf) at says it has a “variable input attenuator.” Cascading amplifiers will however decrease your S/N ratio.

With that particular model you linked, you’ll want to terminate the test ports. See also the manufacturer’s recommendations about connecting cable modems. Finally, if your cablesystem operates at frequencies higher than 870MHz, the amp you selected won’t work. But that ain’t too likely. Comcast operates only a very few networks that run all the way up to 1Ghz; the vast majority of their systems operate at either 750Mhz or 870Mhz.

I had a similar problem that was caused by a defective digital cable STB. The missing channels reappeared after the STB was replaced.

mks57 raises a good point. Perhaps the digital channels that have gone missing on you are because the set-top box you picked up doesn’t have the latest version of the firmware. The middleware may not be able to talk to it correctly.

Well, I have two boxes that are both having the same trouble. They’re brand new (I just picked them up on Saturday). I called their tech support and the guy did something that involved “sending a signal to the box”, which did nothing. I doubt the firmware is out of date, although I suppose it’s possible.

I’m still going to try the amplifier, because that seems like the most logical solution. If it doesn’t work I’ll re-evaluate everything.

Thanks everyone!


I know Comcast can do service calls on Saturday and possibly in the evenings, so you may be able to schedule something convenient. I recommend calling them now just to set up the nearest time convenient for you for a tech to visit. If you’re able to resolve the problem before then, call back and cancel the appointment.

According to the guy I spoke to on Monday, they will schedule appointments M-Sa. You have to be home from 9am-12pm or 12pm-5pm, because they don’t tell you exactly when they will come. It would take me a while for me to arrange to be available for an entire block on any of those days. That’s why I’d rather just try to fix it myself. It may get to the point where I’ll have to schedule a repair, but I’m willing to try the amp first, especially since it’s fully returnable, minus shipping.