You need a pair of 2 amp passive ones if you are going on port one. I have a new pair of PVDP4's, They are the only ones perfect 10 sells that specifically say 2 Amp passive. The freq range on them is 40-2300 Mhz. I do not know how they stack up to other brands. I never needed to install the PVDP4's. I never had any problems with the PVDP3's, though. I did have to replace a couple of the holland 2 amp ones, though I did it with PVDP3's (the hollands are rated to 2150 mhz IIRC). As far as I know, you only need the 2 amp ones if you are diplexing port one on a 44 switch or possibly a 64 switch (something with a power inserter, in other words).