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

[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.