Eduardo, EA3GHS Yes, I am looking at small signal transistors myself now. I am here today to upload a small signal bipolor transistor Darlington arrangement I have figured out for a 40 dB HF preamp. I have it operating with 50 ohm input from as low as 1uV into 50 ohms.
I stopped and decided I should design an inexpensive 0 to 30 MHz HF front end amp for these circuits if anyone need one. Mostly I want to make as many section modules that can be mixed and matched for whatever a soul might decide they would do with such circuits. And the simple ones can act as test modules in LT Spice. I like PSpice and CircuitLogixs also, the later, CircuitLogixs will blow your mind, you ought to Google for it. I got three models to upload now and will have some more on during the week or so. One of todays circuits has 100 ohm I -Q outputs which I think would work well with one of the diode mixer ideas for a all diode QSD. I noticed that in the 1N270 diodes the rate of change of voltage and current plotted resulted in a 10 ohm impedance, so a 100 ohm I - Q amp before the diode mixer would work well I think. Dan ka9rza _____________________________________________________________ Click here for financial aid options. Quick and Easy. http://thirdpartyoffers.netzero.net/TGL2211/fc/Ioyw6ijndC0C7rZBjuAN0WNL2xZH2fGksZfEajZdSs68ZQJJjEuV6k/
