But that's NOT how it works. If you have 40db of signal, but interference is 42db, you're not likely to get ANY signal of any kind. Interference/background noise can be affected by the surroundings, but the design characteristics of the antenna and radio as well as the software will have an impact as to what the phone does. My guess would be that the phones have some kind of algorithm to compare 3G and 4G signal strength along with interference at various frequencies and then tries to negotiate with the tower for whatever the phone or tower thinks is best(as well as available).
So no, you really can't compare them. There's literally nothing you can gain from comparing 2 phones that are different. Even with 2 phones that are the same model but different software, there can be differences. Some of the phones, if you look at the FCCID, actually has multiple revisions as they upgraded the software and changed certain functions.
Really, truely, you cannot compare anything from one phone to the next. The "best" test a consumer can do is doing a speed test on one phone, then the other. Each phone occupies the same physical location and you don't put another phone in close proximity to the phone being tested. Having 2 phones next to each other can cause other problems because one phone broadcasting may cause strong interference for the other phone. You don't see that interference on your db rating though(which is one of many reasons why comparing db is pointless). Of course, this introduces a WHOLE bunch of other reasons why the test is worthless. You're assuming the internet doesn't affect the speed test, something in the environment changes(for instance, a semi truck drives by at the exact instance you are doing a test), etc etc etc.
So again, I'll say it:
This is why I continue to make the argument in the Bionic forum that you CANNOT ever compare 2 phones and make a determination of which is "superior" just by holding them next to each other. Unless you start doing tests like the FCC does, you can only hope for anecdotal evidence, at best. At worst, it's random chance with a little bit of history on how a particular manufacturer has performed in the past.
If it makes you feel better to look at those numbers, so be it. But they REALLY don't mean what you think they mean. Besides, you never really explained why everyone says that lower numbers are indicative of bad 4G when the exact opposite is true. Just kind of goes to show that those numbers don't mean what people think they mean.
If you're really interested you can find some Amazon books that will teach you a great deal about wireless communication technology. Unfortunately, like I said above, most of the cell phones' radio information is a "trade secret" and not provided by the FCC or any other body, so your only indicator of how well a model performs, on average, is by seeing what people say about the phone. My phone(the Bionic) is terrible at 4G according to many people in the forum. The Bionic allegedly shares the same radio as other phones from the same time frame, yet the Bionic has a reputation for just being awful.
But give up trying to compare those little db numbers on the phone. They REALLY don't tell you anything about how the phone will perform compared to another. A yard isn't the same as a foot, and -70db on one phone is NOT -70db on another. The only thing that number would tell you is if you look at 2 phones that are the exact same model and software version you can figure out which phone is performing better at that moment. Of course, that's not entirely a good indicator because some frequencies travel better than others and each phone likely won't be connected to the exact same frequency. One phone just might have a better frequency at that moment.
Those secret "trade secrets" are REALLY what you want to know. That would tell you exactly which phones will rock and which won't. Ironically, I haven't seen any Motorola phone characteristics at the FCC website, but the iphone 4's are clearly provided. They're pretty darn respectable too! I'd love to see a company compare different cell phones and provide that info to the public. Then we wouldn't be able to argue one phone over another. The tests would make it pretty clear which phones are good which aren't.
I have a 3 foot long wifi antenna(looks like a baseball bat) in my house and I can tell you that I get wifi throughout my entire property, as well as 1/4 mile away.
I know just at thing or two about wireless.
Anyway, I'm done trying to explain to you why your comparison is useless. I don't plan to give you a course in electromagnetic theory and radio properties, and you are convinced that those numbers are actually important and provide "enough" value that a consumer should use them to help determine which phone to purchase.