No, it's the scanner that are the problem. The receiver cannot cope with the complex RF enviroments that exists in many places today. I meausered a SDS100 and it's RF perfomance are terrible, as could be expected from that kind of $5 SDR chip receiver.
SDS100 RF measurements
/Ubbe
I disagree, I don't think you could get that SDR chip for $5... 12 to 15 maybe but not 5, I understand what you're saying, it's a TV chip.
Results are going to vary secondary to a lot of factors. For example before the introduction of the filters through two different firmware updates my radio was deaf on Aviation. I also remember not being able to pick up NOAA Weather Radio. Not even the one in my area.
I was very vocal about my disappointment, not only with clipped transmissions and missed transmissions on my P2 tdma simulcast system but the very unsatisfactory analog conventional frequency performance.
The first round of filters came out in a firmware update and Paul explained them very well in the update summary and accompanying thread. It was like a freaking miracle.
Invert filter turned everything around and I was so pleased to see my P2 system working properly.
I immediately went to work on the analog conventional stuff that was just horrible. I noticed immediately the improvements. I also started using ifx then also. The Improvement would go along with your theory of the SDR chip.
I would not use my most efficient and highest rooftop antenna with the SDS it is subject to a lot of interference on analog frequencies not protected by a PL tones, there is no question about it. I do use one of my VHF UHF 800 ground planes with lmr400 and I have to say side by side on let's say marine frequencies which are easy to compare because I'm listening to Coast Guard Sector dispatch, train dispatchers are good for comparison, airport towers are good to use for comparison using the same antenna with different radios and I'm happy to say my sds200s blow the doors off other non SDR scanners...
I'll consider myself lucky and I will also acknowledge the many hours of tedious listening to tweak the filters, efficiently and correctly, I wonder how many people actually do that?
You know better than anybody the variables that can affect reception. Honestly if Paul had not introduced the two series of filters and I didn't start using ifx I would not have kept my first sds100, I was very disappointed with it. I'm sure other improvements in firmware updates made a difference also.
I hope people who are getting bad results with analog will start to experiment more with the filters. It's tedious and it takes time but I feel the rewards are worth it.