Is a lot of signal lost using a 20' coaxial lead?

[idiotbox]

I need to connect several old TV's to RF modulators, which will then be connected to various digital converters to connect to my laptop. My laptop/control station will be about 15-20 feet away from the TV's, so I need to make one of the paths a long one. Is it okay if I made the coaxial cable long or will a lot of signal be lost? Would it better to make the RCA composite cable long instead? Or further down the chain, such as the VGA cable or even the USB cable? Thanks in advance!

[Ed in Tx]

Assuming you are using Ch 3 or 4, and either RG59 or RG6 coax, you will have a loss of 2.4 dB per 100 ft (that's the way they rate it) with RG59, 1.5 dB loss per 100 ft with RG6. So at 20 ft either type, RG59 or RG6, signal loss would be insignificant, less than a half a dB.

[Electronic M]

I've run about 60' from the modulator thru RF splitters and switches (which have more losses than 100' of cable...) and still gotten enough signal to run sets decently....
However since my video rack is in a closet, and I don't keep all my sets within practical coax length of a signal source I started using high power agile modulators to drive antennas for a low power transmission system. I now can tune my signal with a set's factory antenna anywhere on my property, and even anywhere on my block if I max out the modulators output.

[wa2ise]

Some RG59 is poor quality, but most RG6 (the stuff used by the cable company) is usually good quality. Cable companies are much more demanding than the purchasing guys who buy the stuff to sell at Radio Shack. As cable companies buy most of the RG6 that is made, little point in making bad quality stuff.