PSSST Performance Results
I have built about 55 SSB Transceivers over the last 50 years with a few tube type but mostly all Solid State. Some were pretty complex like the multiband KWM-4 and the only one other one that was a low part count --like 10 Transistors was The Simple SSB on my n6qw.com website.
By and large this is the least complex, has the lowest number of Transistors and actually is one of the best performers! I am at the kicking myself stage for not taking this approach many years ago. Who said Simple is Best? Well they were right!
Thus having built so many transceivers I have a very good idea of what is working well versus what is barely working. So I can just lisetn to one of my transceivers and just know where it sits on scale. It goes without saying I do have an internal list of Check Off Items as Metrics.
In order to measure performance there must be some criteria and then a test against that criteria enables an evaluation of performance. By simulating the circuits in LT Spice, we had a fairly solid idea of how the circuit modules would perform before soldering anything.
We knew the gain and frequency response of the Mic Amp/Audio Pre-Amp as well as the performance of the Steerable RxTx Amplifier Module. The IF Module simulation gave us a feel as to how it would perform with a filter installed. The Band Pass and Low Pass Filters were our Go To Ciruits so their performance was well known and used in many rigs. The same applies to the IRF510/RD006HHF1. The Driver Stage with the 2N2219A has also been employed in many of my transceiver projects.
Thus the only unknowns as to the ciruits being used were the Steerable Modules and the Microphone/Audio Pre-Amp. If you read between the lines we were building in success by building upon known levels of performance. You can't imagine the thrill when you hear "It really sounds Good!"
Some changes were made after the 1st few contacts, For one we swapped in the RD006HHF1 for the IRF510. The other change was the emitter resistor of the Steerable RxTx Amplifier circuit. The emitter resistor was initially 51 Ohms. Smokin Hot is a good description and I also found on one very loud signal there was a slight hint of audio distortion. Too Much Gain! Successive simulations with 100, 180, 220 and now 390 Ohms has reduced the stage gain by about 2 dB.
Now the 2N2222A runs a lot cooler and signals are amplified and no hint of overdriving the gain. It is a good balance. There is something terribly noisy in my neighborhood. Pull the antenna connection and the receiver is like dead but reconnect and you detect the noise. Actually I saw this with several other transceivers in my shack including commercial units.