I am looking for two Terrestrial/Satellite Diplexers (one each end). There are a few on trademe and freeviewshop but they have differing frequency specs. Are they all suitable for NZ frequencies? 

The freeviewshop one says 5MHz - 2450MHz 4db loss aprox $15
This CAE-103AUV says  40Mhz - 2300MHz 3db loss $5.25
GECEN CG02-01 says Ant 5-850MHz, Sat  950-2150 3db loss MHz $10

Also, these have between 3 & 4 db insertion loss. What effect is a total 8db loss going to have on satellite reception? I have a 90cm dish with about a 40m RG6 coax run. My Topfield TF6000 has around 73% signal strength for freeview and 68% for SBS. Not sure what db level this represents.

Regards Allen.