New to Radio: Question about Signal Meter on Barefoot Radio

The signal meter: should I have more or less signal bars when RX, and squelch set just above speaker on.

In other words, if I have 4 bars showing now, with no noise unless someone talks, and then my system (antenna or other part) is improved, will my bars increase or decrease when no one is talking? Or stay the same?

...I'm an engineer, so pretty technically minded, but I can't wrap my head around this one.

Thanks for the help!

--
Brad

 

Additional info: with the engine off, I get 4 bars. When it's running, about 5 or 6 bars.

when driving down the highway, the white noise sounds much "rougher" and the meter flickers quickly from 4 to 6 bars.

Then I shut the engine off and back to 4 bars and white noise is "smooth"

does all of this mean my antenna or unit isn't grounded? ....I really need an experienced person here..