Ok, let's do the math. dB = 10 log (600/400) = 1.76 dB. Hmmm.... not much. That's the difference you should see using Netstumbler or the typical laptop signal strength indication.
As for the range increase, range doubles for every 6dB increase in system gain. So, a 1.76dB increase will yield: range_increase = 10^(1.76/20) = 1.22 time or a 22% increase in range.
To get a 50% increase in range, you would also need to improve the receiver sensitivity. Since most units are running near the best sensitivity that can be achieve with current technology, that's not going to happen this week.
I didn't think You-Tube allowed commercial advertising. Incidentally, I suggest you ease up on the confusing model numbers. Unless the viewer already owns one, I doubt if the long model numbers mean anything to a prospective buyer.
Good luck, and please lay off the miraculous claims.
I'm not sure they can do much more with non-cryogenically cooled front ends. Most are SiGe or GaAs. The front end noise figures aren't going to get much better without cooling. With integrated chipsets, the minimum sensitivity is typically set by the internal noise pickup, not by the NF.
It would also be nice if they would stop lifting the numbers from the chipset data sheet and actually test for sensitivity. So far, only DLink seems to be supplying real numbers. Everyone else lies:
Personally, I'd like to see the RF section seperate from the digital stuff, so I can install it high on top of a tower. Alvirion has had this for a long time, but it's expensive. Note that this implies a receiver front end that can handle some serious overload and not go into blocking in high RF environments. Incidentally, that's one application where a tower mounted power amp and pre-amp can do some good. However, the rx amps in the boxes that I've seen are actually worse that what's in the access points.
The whole intent of SiGe was heavy integration. I don't think there is enough money in SiGe stand alone amp chips, or perhaps better stated the money is in the system on a chip. Agreed that the RF on a different chip than the logic would be better.
Incidentally, I got a 2400Mhz video receiver. There is not a lot of
2400mhz video, but there is enough that I bet some people wonder why they do their site survey, find a free chanel, then wonder why they have problems.
Probably true for individual transistors, but there's quite a bit of SiGe in use in the form of simple downconverters and RF front ends. For example:
Most are in the 1.5 to 3.0dB NF range, which is nowhere near the 0.4dB NF that can be achieved with a properly optimized discrete GaAs FET design.
Yep. Lots of security cameras are also wireless. The TV video "rabbit" links are suppose to only occupy perhaps 12Mhz (double sideband, not VSB). In theory, they only trash a few channels. Anyway, that's why I use a spectrum analyzer for dealing with possible non-802.11 interference.
I worked for Maxim at the time they got their SiGe working. Those engineers were nearby, so I would visit once in a while to absorb what I could absorb. [I'm a baseband guy, not RF engineer.] Maxim made those building blocks because that was all they could do. That doesn't mean it was a good market. I'm not sure how many of the RF engineers are even there anymore. My last contact with the group quit for a start up.
The RF guys had a hell of a time measuing the noise figure of SiGe. If there was a market, you could make nearly impossible to measure amp in the VHF band up to say 400MHz. The input stage had to be sized differently, though I was told you could parallel the building block amps to do this. The trouble is bipolar amps were pretty good in that frequency range, so there was no market.
Same here. I can setup a measurement twice, and get two substantially different numbers. At one company, I had to setup a temporary RF shield room to get fairly consistent numbers. See Fig 3-1 on page 12 at:
for a clue.
For 150 to 400Mhz, I prefer cheap Dual Gate MOSFET amplifiers. They have almost the same noise figure as GaAs in the VHF frequency range. The NF of bipolar is far worse. The big different is in handling intermod and blocking. The Dual Gate MOSFET can handle much more signal than either bipolar or GaAs as shown by its much higher 3rd order intercept specification.
However, at 2.4GHz, things change. The DG MOSFET won't work at much above 500MHz. Si bipolar is rather noisy above 1GHz. That leaves GaAs FET and SiGe by default.