Originally Posted by NBPTFF8
i know nothing of how the amps work just a shot in the dark any ideas or suggestions
The ability of your system to receive a signal depends primarily upon the signal level into the first active stage and the noise figure of the first active stage. By first active stage I mean the first RF amp in your scanner, or if you add a preamp, the preamplifier.
Where preamps make a lot of sense is when there are high losses in the coax between the antenna and your scanner.
Coax losses are much higher at 800MHz than at 155MHz. Coax losses in RG58 is much higher than the relatively cheap RG6 quad shield
By locating the preamp up at the antenna
itself, the full signal received by the antenna goes into the preamp. The preamp then amplifies the signal from the antenna enough to compensate for the coax loss so that the additional noise from the scanner front end is small. Locating the preamp next to your scanner doesn't help. The preamp specs you linked to show a 3dB noise figure. That isn't really all that good and is probably worse than the preamp in your scanner, so adding the preamp down next to the scanner would probably make your reception worse.
Do you have a line of sight to the tower that you are trying to receive? If not, then raising your antenna will probably make much more of an improvement than a preamp.
There are lots of knowledgeable people here on RR. To get the best advice it would be helpful to tell us:
1. What frequency? (exact not needed. Just 800 vs. 460MHz vs. 155MHz...)
2. What type of coax and approximate length?