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Antenna dimensions?
Jeff Liebermann wrote:
I beg to differ. Unless I missed something in my post-midnight scan of the specs, the wireless router's TX power is set and forget. If it receives an extremely strong signal level report in the 802.11 management packet, the power remains the same. The ability to do power control is there (because each device reports its RX signal strength and SNR) but very few access points even try. You are speaking of the specs on the USB card, I am speaking access point ... and actually, I have never searched for power-throttling in the USB card, I simply would not use it ... when the wife and I go out and I search for APs, I want every possible mw in action, at a clients, hotel, hospital, etc. Having one side of transmission link error free is MUCH superior to have both sides error prone! I beg to differ. You're creating un-necessary interference. Let's play with the numbers. Let's not, I said what I meant, and meant what I said, one side error free is better than two sides error prone. The commodity wireless router belches about +12dBm. Yours is allegedly +27dBm. Range doubles for every 6dB increase in TX power. Therefore, your TX range is: (27 - 12) / 6 = 7.5 time more than would be with a commodity wireless router. In terms of coverage area, that's: 7.5^2 = 56.3 times the area. Assuming a uniform density of WLAN users in your vicinity, you're trashing 56.3 times as many users or systems as necessary. No problem. I don't live in a dorm, trailer park, high-rise or apartment building ... the software will automatically adjust to find the best chan and recheck this decision, from time-to-time. If others don't have that capability, they may wish to upgrade ... like I have strongly implied, already, "If your AP is crap, toss it out!" I can't imagine anyone here who failed to read specs before purchasing, however ??? You're also partly wrong about asymmetrical systems being superior. The transition between a fairly good BER or PER (packet error rate) is rather abrupt. What happens is that the AP simply slows down the data rate until the PER improves. Since the connection speed can be different in each direction, you'll get very good speed in one direction, and probably very slow speed in the other. In addition, things go insane above 54Mbits/sec connection speed. You might have enough signal to go faster than 54Mbits/sec in one direction, but if it's lacking in the other direction, the AP will simply revert to 802.11g and limit the speed in the stronger direction to 54Mbits/sec. That's not a problem as few systems can operate reliably at 54Mbits/sec beyond a few meters range and in the presence of interference. The equip can do b/g/n (b&g for the usb card in question, multiple computers here) With a windows widget to monitor my ap/card connection (transfer rate, errors, signal strength, etc.), I see it rise and fall from time to time. Sometimes I have seen the connection renegotiate from n to g to b ... however, at this same time AirSnare has went nuts. Seems wardriving teens are to blame ... grin I was a teen once, so long ago, I fear I may forget ... :-( But, I will tell you, if ever I notice a problem with the errors (just looked, 3 errors), I will remember your words. Meanwhile, you're operating an alligator, jamming 56 times as many users as necessary, and polluting the airwaves with your overpowered xmitter. It's like operating a kilowatt xmitter in the middle of the QRP frequencies. Your stuff gets through, but nobody else's. I suggest you do the math, repent your evil ways, offer sacrifice to the radio gods on the hibachi, slap yourself on the wrist several times for penitence, and stop playing with the dark side. Although, I am sure one or two of my neighbors are savvy enough to set their routers into non-broadcast mode of the SSID, and have WPA and filter on mac addresses, I just don't see the traffic/jam you speak of. But, like I say, if I do, I shall remember your words. However, although I have a pocketfull of various USB dongles, my external USB wifi "card" is the highest output I could find which is cost effective (@ 500mw.) External USB being powered off the USB buss must stay 500ma (@ 5v) or below, total consumption. And, would more than allow for a 1 watt USB dongle. You would do better with a directional antenna, so as to not both pickup and deliver interference from other systems. Antennas with gain also improve the system gain in both directions, thus preventing the creation of an alligator. No, I would NOT. When I take my laptop and USB antenna analyzer out to the antenna(s), I appreciate my omni. When I take my laptop and USB ODB II out to the car (in another direction), I appreciate my omni. When teens go by wardriving and trigger AirSnare warnings (and giving me one-hell-of-a-kick!), I appreciate my omni. You hang around with the old men here, beware the cynicism, it IS contagious! Here is a USB card to match my router: http://www.data-alliance.net/servlet...802.11n/Detail Try one, you'll like it, "Mikey does!" grin Nope. Instead, I was instrumental in convincing at least one mesh wi-fi vendor to reduce their poletop TX power, as they were causing most of their own interference. Asymmetric systems suck. Beware. Again you risk being controlled by the control freaks here. Glad it works for you, attempt to enforce it for me, we have a battle .... you know, there is equip and hacks available to open up chans far in excess of what is legal, I am sure some are savvy and use them ... perhaps teenagers? straight face I have even heard of some flashing their ap/cards with the foreign version of the software for them and exceeding power/chans ... shame on them! :-| Regards, JS Bah-Humbug (T'is the season). However, you provide good discussion, and have valid arguments, I am sure--some will agree with and appreciate--perhaps even some which are state-of-the-art! Personally, I would NEVER suggest purchasing an AP/card with less than 350mw capability. And, only then if you get one-hell-of-a-buy. Warm regards, JS |
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