brmadhukar,
The very first stage of you system establishes the NF so you cannot escape using an LNA with having better NF than the one you have now.
There is a simple shareware software for studying system design with NF etc issues: RfWorkbench from Kirt Blattenberger, see
**broken link removed**
You can enter your system in block diagram forms with the appropiate data for each block (gain/loss, NF, IP, etc) and you may play around with the numbers to find a solution for your problem.
to cswang:
Thanks for the interesting info, I have not read that.
rgds, unkarc