I have a couple Radio shack 4 way amplified splitters laying around the house. Could i connect this to my outdoor antenna for better reception or stick with a non amplified? Im going to run about four radios on one antenna.
You can try it, but in most cases it will only make signals worse.
The best test (without test equipment) is to find a few frequencies in each band that come in very poorly, but consistent. (you can hear the voice, but they have a good bit of hiss and noise).
Then test each one with the amp in and out and see if it helps or hurts.
A typical 4 way non-amplified splitter will reduce the signal by about 7dB per output. How much signal do you have at the input? Can you "afford" to lose 7dB to each receiver?
I am using a non-amplified high quality TWO way "cable TV" splitter to split my discone to two scanners. I run another scanner on an RS800 because it is only receiving 800MHz and does just fine w/o the outside antenna.
However, I just installed several scanners for someone and because the loss was going to be more, I used this amplified "splitter". I also added a band stop filter at its input to remove broadcast and other unwanted signals before amplification. (4 way version)
You can't look at it that "more is better". You really have to know the signal levels you are dealing with (from the antenna), if there are any unwanted strong signals, and then if you use any amplifiers, make sure they are low noise and a good fit.