I tried the newest Televes 560483, and though I can't really find exact specs on it's noise rating, It's got to be OVER 4db, from my tests. That's WAY too high, IMO. The Kitztech KT-200-Coax pre-amp beats it without even breathing hard.
I think this requires some clarification. The 560483 is a poor choice for your application. Please, allow me to elaborate. This dual broadband input preamp is intended to provide a solution to combine two broadband antennas on a budget, as such, it has an input broadband combiner, which inevitably increases the effective NF of the system. It is a great solution for many scenarios where a customer wants or needs to combine two antennas overlapping bands, but due to the nature of the combination, it is quite obviously not the ideal choice to be used for just one feed, be it coming from a broadband antenna or by diplexing several band-specific antennas, particularly in a fringe situation, as in that case the system is losing precious C/N by the broadband combination that it might need to meet the decode threshold. Not because the amplifier is "bad" by any means (it actually provides much better filtering, flatness, and gain regulation compared to most of the commercially available amps currently offered in the market) but because of the input RF combination needed for the intended application. This is actually mentioned in the amp's manual:
The actual NF of the active itself is pretty much in line with that of the unit you are using (which is not .4dB). The right product for one feed would be the one input, P/N 560383, or in a fringe situation with two antennas, use two individual preamplifiers and combine after, once the aerial feeds have been preamped and the NF of the system established. I hope this clarifies a little better. These are really very good units when used as intended. If you have the opportunity I suggest you try the 560383, which provides the most accurate repack filtering in the industry nowadays and individually adjusts the VHF and UHF independently ensuring an optimal amount of gain is applied to each band over time avoiding overload.