I want to say that I completely agree with what was said here in the response of the original topic of this thread, specially I fully agree with what scrim said which is backed by Hpasp's data regarding detection ranges.
In complement to what was already said here I want to say that Stealth doesn't mean that's completely "invisible" to a radar, in fact almost any radar can detect any Stealth aircraft. What happens is that a Stealth aircraft (F-117 or F-35 for example) is always detectable by a radar source (doesn't matter the type or band that it uses/operates) at a much shorter range when compared to a Non-Stealth (F-4 or F-15 for example) or to Semi-Stealth aircraft (Super Hornet or Rafale for example).

I'm going to be on the generic side here:
- Imagine a radar that can detect a Stealth aircraft at 20Km (twenty) for example. This means that this same radar will be able to detect a Non-Stealth at much longer ranges, in the range of hundreds kilometers - I would say 200 (two hundred) kilometers for example.

- Now imagine that someone (doesn't matter who) is able to make some considerable progress in radar technologies, perhaps even using cutting edge technologies, perhaps using it together metric band radars and that this sort of new technology manages to detect a Stealth Aircraft such as the F-35 at ranges of 100km! This would certainly be a great achievement and I wouldn't say impossible, but again lets imagine this (still) imaginary radar which is able to detect a Stealth aircraft such as the F-35 at ranges of 100km, what would be the detection range of this same radar when detecting a non-stealth or even a semi-stealth aircraft such as the Super Hornet or Rafale for example? 700-800km or perhaps more?
Taking this "academic" example an knowing that currently (and in the future) there is (and will be) a considerable arsenal of air launched weapons with ranges in excess of 100km, I say that a Stealth aircraft such as the F-35 can still be able to avoid and even destroy such radar systems without ever being detected!
The same cannot be said regarding Non or Semi-Stealth aircraft since there isn't any air launched weapon with a range in the excess of 800km, at least for a fighter sized aircraft that I know of (Large Bombers such as B-1, B-52, Tu-95, Tu-160, etc... may be a different matter).