Hay Bill, thank you so much for the detailed explanation.

I already see few points where the improvement can be done (the analog supply 1,8V of the SGTL5000, the SGTL5000 itself and so on). Just to do it a bit more quantitative, or in other words to make easier to compare, correct me if I am wrong but I think the Noise Figure (NF) is a good indicator to compare receivers. Coming days will try to measure the NF of the current design.

Here is the algorithm I plan to use, and if you see some flaws please correct me

1. Will calibrate the dBm meter of the receiver let say at 80m band (3.7Mhz) with signal generator and attenuator

2. At the same gain settings, with terminated 50ohm input will measure the salve noise Psn of the receiver in dBm

3 Then NF = Psn - (-174dBm/Hz + 10 * log10(BW)) where:

NF is the noise figure. Psn is the measured total output noise power. -174dBm/Hz is the noise density of 290°K ambient noise. BW is the bandwidth of the frequency range of interest.

Once having the NF can start modifying and see if there is improvement or not, very curious what it is possible with my design