I recently installed a security camera w/ modulator. I've done this 100 times w/ no problems however this time I was unable to get a good picture on any unused cable station. Tried running modulated output to individual tv's (no cable input) and it worked just fine. Just wondering if something has changed and now there is some sort of signal on all cable channels. Client has digital box on one tv, but is not concerned with that one. Can the digital box be creating a problem for other tv's? I'm pretty sure I can use a notch filter with the modulator to make sure I get a clean channel, but this is pretty expensive for what I'm trying to do. Any ideas?

um you need a notch filter and you can find them for less then $20.

The digital cable is your problem and using a notch filter in this case could be very bad. The cable company uses several different channel frequencies for things such as the program guide, Video on demand, and cable modem service to name a few. These channels appear to be snow however there is a carrier on the frequency. That is why your modulator looks like crap. There is also a good chance you are interrupting one or more of his cable services. Granted you may not know that if it is something he currently doesn't use.

That said you need to get a channel map from the local cable companies. It will tell you what they have where and what channels are available. Hopefully there will be a couple for you to choose from.

Robbie S

as long as you dont put the filter before the cable box youll be fine.use 2 splitters 1 for boxes(unfiltered) and one for direct feeds

You can also try to use a low-pass filter at channel 126. I don't know about your cable systems in your area, but here you can low-pass and place your modulated channel on 128 (just make sure all tvs they want modulator on are new enough they go up to channel 128).

The only other problems I have had deal with HRC cable system, IRC modulator, and tvs that wouldn't automatically switch between the two.

Luck

Matt

Robbie S is right. Don't go trapping anything. I don't know if your Cable Company is as cooperative as ours here on Long Island. If so, getting a channel map will only be a dream.
Try an agile modulator. wire it up as usual and try it on different channels, your bound to find one that works.
Good Luck.
George

I'm gonna say go w/ Vincent's post 4 and deisle's post 5. Just create two cable systems. Take your incoming feed, split it, one goes directly to the Digital box (or boxes), and then the other goes to the standard tv's w/ a LPF and the cam channel. Good luck.