40/80m HF preamp : I doubled the gain !!!!!!!!

Hi,

Yesterday, I had some time to finalize the preamplifier...
Because I had all the components twice, I decided to place in serie of the first preamp a second one as per the schematics of the first one...Eerything wored fine from the beginning !!!!!
The most difficult was to fit the 2nd PC inside the aluminium box which was already quite full, but It looks like it did it well.

As for now, I estimate the gain to be over 35 dB (20dB for each preamp, 2 dB losses in the filter + extra losses in the connections).
I made just a few experiments yesterday evening :
The V55V/P which was 5/5 went up to 5/9+5 dB!
A GM station which was 5/7 on 80m went up to 5/9+20dB !!!!!!!!!!!!!!
A OZ station which was close to 5/9 on 40m went to 5/9+30 dB !!!!!!!!!!!!!!
(Never saw the S-meter of my FT-920 going so high for a report...My FT-920 is really not generous, and max reports I'e seen so far were real 5/9+10dB max)

Problem is that on both 40 and 80m, the signal is increased, for sure, but the noise also. What is interesting is the Signal over noise ratio, is it increased or decreased? I purely estimate that in the worst case, the S/N is identical, and in most cases, it is better with preamp ON.
Without pream, the noise floor is close to S5...
With preamp ON, it became S9

That's close to 20-25dB of noise increase, while the wanted signal is increase by 30dB..So I've got 1 S-meter point (6 dB) improvement on S/N ratio..

More deeper tests have to be done, this is just the result of my first trials.....

Also, those tests were made using the HF2V, which is somehow noisy....I should re-do the same tests using my RX antenna (a pure 40m dipole) and see the effect..

But in all cases, I know have a 30dB (min) HF preamplifier including band-pass filters for 40 and 80m, with the possibility to connect a dedicated RX antenna, and supporting the 100W of my transceiver.

This is what I wanted, HI !!!!!!!

I promise, pictures will be added VERY soon,

73
Ronan, F8AFC