You're stats on the realignment look pretty good, there's of-course, the Grey area of what can be discerned when in actual real world events like Propagation events and ambient noises in proximity to the receiver and the antenna and the ability to process the dynamics of the signals embedded in the noise.
Many don't look at a Cobra 29 as the ultimate in receiver technology - they just want to know the traffic up ahead or maybe the local time so they can figure out the Time Zone change..
But the real proof is in the shouldering of the Filtering from simple ceramic resonators onto the Xtal approach.
Now in the newer non-Discretes' - they have an issue of "White noise" - they are forgetting a simple process that actually
increases the receivers noise floor, but at the same time - DECREASES the Signal to Noise ratios...They did away with a simple Electrolytic or Tantalum filter smoothing cap - which "drags down" the compression effects caused by the quicker response the IF signal capture to AGC action - a simple regulation problem. You need an Analog delay to the AGC loop - too little the White noise appears, apply too much, the signal and it's swing in carrier - causes a level of distortion making the receiver appear like it's overloaded.
So out of the box I was actually -107.5 and after some twiddling I am down to -109.4dBm@12. I am thinking this about what I should expect?
I did manage to get the TX freq right on and cleaned up the 2nd harmonic. The modulation was actually set real low and with a better mic it has some punch to it now.
Over all I think I am happy with it
You're in a realm of performance that requires a good clean reception and open air approach to capture that performance on a regulator basis - it is a challenge.
Just Some examples of 2nd IF strips that use a "cap" (C18 - note Value used) to help make an otherwise fast tracking compression effect - slowed down to give the audio envelope a linear curve on an otherwise tight compression circuit design.
Cobra 25GTL - Note C22 Tantalum
Your Cobra 29 - Note C27...10uF
Each subsequent design has it's hits and misses, but the overall effects are to make the receiver more appealing to the listeners ear than to provide high-performance capture and processing.
So you know, not everyone whom manufactures their radios, does this little warm welcome effort to their radios - they either skip the parts needed for the sake of economics or they never paid attention to what the end user needs to hear, versus wants to hear - they can be two vastly different things to deal with.
IF you listen to how some people use their radios, this seems to be more of the inherited trait of the background radiation noise one must account for - than a true effort of others willing to trying to, communicate.
No matter how you look at it, enjoy the learning curve - I'm sure you'll be making quite a few friends along the way.
