Just to clarify the difference between the 2m PGA144 and the VLNA preamplifiers.
The PGA144 preamp incorporates both a notch filter at 98MHz cf as well as a carefully designed 130MHz HPF. The combined HPF and notch together create a small but significant reduction in 144MHz input circuit loss, hence improving the noise figure at 144MHz. This unusual, and possibly unique, arrangement was suggested by G4SWX some years ago during development of the PGA144. It follows on from some older low loss HPF input work by DJ7VY, LA8AK and others.
The low Q bandpass output filter is designed to not only enhance gain at 144MHz but also to roll off gain above the band.
The variable output attenuator allows gain setting as required.
The PGA144 is not a high gain, wideband, preamplifier, like the VLNA designs, which are meant for EME where second stage contribution needs to be minimised together with the lowest loss input matching arrangement.
The dynamic range of the PGA144 is way above most earlier GaAs mesFet and HEMT preamplifiers. You need a pretty good following receiver to take advantage of the PGA144 dynamic range!
73 de Sam, G4DDK
On 8 d 130MHz HPFJan 2021, at 18:04, David Redman <nt I@...> wrote:
Yes Sam's preamps are excellent for low noise and high gain, just what you need for dish mounted preamps.
Dedending on da to be minimisedyour local RF signal levels 50 to 1600MHz for terrestrial use and depending on your levels of Band 2 FM, 220MHz ish DAB, UHF digital TV and then cell phoness gain setting plus reminent vhf / uhf pmr plus pagers you may need a decent BPF ahead of the pre-amp.
I use Sam's preamps on 2m, 23cms and 9cms EME and they are excellent but be aware for tropo use they are relatively wideband input.