CW RX Update: RF Preamp 2

So i got it all built, for some reason the gain adjust is not working and I need to investigate that to see why but other than that, it seems to be working and the gain is about what was predicted in the simulation as can be seen by the scope output below. So I will fix the few bits that need fixing and then move onto working on the IF filter. I think this will do the job required quite nicely.

Oh and I have worked out whats going on with the variable gain, Q2 is a current source, so it supplies more current to the amp above, not less, so what I need to do is redesign the amp to have the MIN amount of gain required for my circuit, then use Q2 as a gain boost. Now that I understand what is going on, I can redesign the circuit to have 3 to 12db gain swing. More than enough for the kinds of girls I go out with.

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CW RX Update: RF Preamp

So i have merged the separate simulations together into the one file now to get a better understanding of how they will work together.


And the simulation looks promising, they seem to be happy working together.

So now I have built the RF Preamp onto the perf board with the bandpass filter. The only testing I have done so far has been checking for continuaty as i go along to make sure A goes to B and does not short to ground hehe. I still have to add in the pot for setting the amount of gain in the amp and to wind the 200 ohm to 50 ohm transformer that goes on the output of Q1. Its actually nice to see this moving along, lets just hope it works. HIHI.

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