50ohm RF VGA 3db - 18db(or more) low noise 12v 450 - 750mhz

[benyB]

Hi, i'm looking for VGA modules with these specs and was hoping to avoid having to make my own. any ideas?
I found loads of high gain low noise 50ohm modules but no variable. I need to tune the gain to the receivers..

450mhz - 750mhz or larger
12v or 5v ( pref 12v )
adjustable gain 3db - 18db or higher
50ohm input/output ( not differential )
low noise
low power
I'm really needing a duel channel since i want to use in a diversity system but can live with 2 x modules.
i'm looking at increasing gain from a diversity Log Periodic Dipole Array antenna before it goes into a 1 - 4 splitter. basically an antenna distribution amplifier.

I'm assuming its best to put the amplifier modules at the antenna(s) and then split the signal at the multiple receivers end as to not amplify the noise from cable ?