Has anyone used one of these to enhance their cable signal? Do they work?

Thanks for the input.

They're great at boosting the noise.  Even the good quality ones like the cable company uses are pretty bad.  For our cable at work, we had to get the cable company to remove the amp closest to our building and reduce the gain on the one down the block in order to get our cable modem to work.  Yes the signal was stronger with the amp, but the SNR was just too low for the cable modem to work.  The signal is now -11 -dBmV with a SNR or 35 dB which isn't quite good enough to work 100%, but it's better than when it was over 100 times stronger (+10 dBmV) with the amp, but had a SNR of only 20dB.

If your cable signal from the cable company isn't strong enough, then you'll have to get them to fix the problem.  They have certain minimums that they have to meet, and you'll never need to add your own amp.  I know it's hard to fight them since they have a monopoly and simply don't care how bad their service is, but you can fight them through the local government.  For us, the county administrator's office handles that monopoly, and after five years of fighting, we finally got them to fix the cable to our office.  If you know someone in the local government, you may even be able to get the cable company to work even faster than that.z