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This is a more traditional regenerative stage. It has the 'tickler coil' set-up. Unfortunately, in EC, this will not work properly as there is no way to obtain coupling between the two coils in the circuit.
THIS CIRCUIT IS BASED ON A VERY POPULAR DESIGN CREATED BY PAUL HARDEN (NA5N)
Antenna input amp (not shown) receives INPUT= (1-20 millionths of a volt). This high gain amp presents 200uV to the regenerative stage. (Note, the antenna and preamplifier are simulated with a signal generator)
The regenerative stage works with cap coupling and feedback from the tickler coil. In the DR2 scheme, the coil is more complex and has a transformer. This does not look good to make and problems have been reported. The first version of the receiver had a coil design that was more practical and actually works.
Gains of 100,000 are possible!
However, the rest of the DR2 seems to be better or simpler. I like Paul's use of a phase splitter and differential amp with common mode rejection. I'm not sure that it's necessary, but I like it. Here, I've just concentrated on the regen stage. There's not enough space for the whole circuit anyway.
Note: this simulation is tuned to work at 7 MHz. The switch shown will work, insofar as it will change the tuning to the 20 metres frequency band, but then the stage will need retuning. This is easy to do using the bode plot.
Check out the desert ratt 1&2 on Paul harden's website.
http://www.aoc.nrao.edu/~pharden/hobby/Hobby.shtml
(Oh sorry, I forgot to welcome the normal inane, mind blowing idiotic comments from engineering students who've never touched a soldering iron.... Bring it on!)
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