Oupei

CATV RF signal amplifier

hi, I have regular analog cable tv and internet and I want to split it 7-8 times to really long cable runs so I assume I need a signal amplifier. The signal is currently already split twice and running across the whole house and it's not exactly crystal clear, but I checked where the cable enters the house and it's perfect there, so I guess that's the best place to put the amp.

First off, is it possible to amplify the signal too much? or does the tv know what the maximum amplitude is? would it hurt to amplify more than the 3.5db that each split removes? Also, whats this bidirectional stuff? do I have to worry about an amp not being bidirectional?

I went to radioshack and I saw a few models. In particular, i was wondering about one that didn't have a power plug and was promising 12-15 DB gain. how would these things work without external power?

Jim Rakowiecki

Oupei, The best way to do this is to "homerun" the cables or run everything back to one large splitter rather than placing many two way splitters along the way.
You are correct in that each two way splitter loses 3.5 db so if have 8 two way splitters in your house by the time you get to that last TV you've lost 28db which will put you well into the negatives and result in a horrible picture.
One eight way splitter will lose 10 or 11db and the signal amp will offset that loss but to over come 8 splitters you will need three amps and probably still have a lousy picture at the end of the line. Every time you split you increase your chance of having problems with ingress and signal loss. Uninterupted cable runs are the way to go.
If you put a 15 db amp before the eight way splitter it wil compensate for the signal loss and add a little to help overcome the cable loss so you will end up with a signal comparable to what is coming into the house at each TV.
Yes, you will need to have a two way amp if you want to use the internet or digital services. It is also possible to over amp a signal and burn out a tuner but if you do it the way I've described it shouldn't be an issue