looking for a preamp to cover the frequency range of 162 - 174 for a RS 197 scanner. Looking to pick up the forest service channels. I just a little out of range. I can pick the channels up just a little fuzzy.
If you live away from populated areas then a preamp can be useful, but if you live in a rf rich environment then investing a little more in your antenna(s) would be wiser, since a preamp would create more noise and intermod than amplified signal.
I live in Mesa, AZ about 45 miles from phoenix, I have a discone antenna and I use LMR200 coax about 20 feet of it. I have the frequency range set up as NFM instead of FM. The closes repeater for the forest service is about 40 miles away up in the hillside. You can hear them talk by the volume is very low and at times it comes in fuzzy. I am using the ATTN button on to bring them in. If I turn off the ATTN button I can not pick them up at all.
The gre super amp is a good one, i have three of them, one is in line with a 536hp with a monitor52 antenna, and one in line with a bct15 in my mobile unit, Gewecke is right if your in an area saturated with transmitters they would cause more trouble then there worth band coverage is 25 mhz-1.3 gig adjustable or off, i power mine with nine volt power supply's they don't last long on nine volt batteries, hope this helps
If you have to turn on the attenuator, then it sounds like your scanner's front end is getting hit with strong signals (unwanted signals). A preamp will likely make it worse.