Fry's cheapie: Airlink AWL5025 $15

snipped-for-privacy@sushi.com hath wroth:

snipped-for-privacy@sushi.com hath wroth:

The links work just fine. They're assorted photos and data for a Gemtek USB 802.11g wireless client. It's a dual antenna (diversity) system, where one of the antennas is external and the other is on the circuit board. The FCC Data mumbles MIMO, but I don't think so.

That's because the FCC ID search page has been broken since it was introduced.

Yep. That's exactly what I do.

I have no experience with the Gemtek USB client. Sorry.

I plugged it into my x64 system and it found a driver. [The Airlink 101 items I've bought thus far have had 64 drivers to my amazement.] Netstumbler can't use it. The supplied site survey software works. I'll have to test it on my own system since all my neighbors have turned on encryption. [That wasn't always the case. ;-)]

Next up is to put a small RF connector on it. [The B mode is 50mw. Not too shabby.]

I have had this happen to me, usually after saving a bookmark into one of the links from a previous successful search. Try clearing the cache in your browser, and begin a new search from one of the top level forms.

That's my favorite way to install any Wifi device since WinXP-SP2. It used to be a bad idea, but now it works well, often better than the latest drivers from the labelled vendor.

I thought NetStumbler worked with about anything, if you set it as NDIS5. I think my Netgear WG511 is one of those, but I can't recall.

Is this "Airlink AWLL5025 MIMO USB XR 802.11g Wireless USB Adapter "? You left off an "L". Or is the $15 unit missing an "L"? ;-)

$29.99

Yes, I left out one of the L's, i.e. it is AWLL5025.

I'm running 0.4.0. It finds the airlink box in the devices section, declares it NDIS5, but the adapter not present icon flashes at the bottom of the screen.

I opened the box up last night. Pluck the rubber feet and remove 4 screws. The pcb just drops into the plastic should you want to put it in a different enclosure. [Plastic until you don't want mimo.] The antenna is held on by soldering the coax. I'm going to replace it with a SMA jack.

got the AWLL5025 from local Frys for $19 + tax. The survey site software detects a total 6 networks in my ghetto neighborhood, my WRT54G running DD-WRT in client mode with 100mW of TX-power and 9dBi ruber duck omni can do no better...

Netstumbler works with this adapter but cannot detect SSID of some stations, Cain&Abel do all...

i gave my brother the PCI version of this RaLink-based adapter, the AWLH5025 PCI which i also paid $19, and it can see more networks than his D-Link DWL-G520M MIMO PCI, which he returned to CompUSA for $100 back

heck... i even bough the Atheros-based AWLH4030 PCI, paid $14 at Frys, that can run Commview for WiFi.

oh and by the way, wireshark. formely ethereal, says the TX-power of this card is 100mW!!!

cheers

snipped-for-privacy@sushi.com wrote:

snipped-for-privacy@scn.org hath wroth:

Which one? The spec sheet says that the AWLL5025 belches +13dBm (20mw) for 802.11g and +17dBm (50mw) for 802.11b.

The AWLH4030 PCI is about the same at 10-14dBm (10-25mw) for 802.11g and +18dBm (63mw) for 802.11b.

So it is written, so it must be.

Wireshark and Wi-Fi Hopper both claim my HP laptops Broadcom something MiniPCI card puts out 1300mw. What's happening is the NDIS5 function call that returns the tx power from the driver is returning garbage.

oh, i mean the USB AWLL5025 card and the PCI AWLH5025 too, wireshark won't return the TX-power value for the AWLH4030 PCI, the program also notes that the accuracy of the returned values solely depend on the card's drivers

so the broadcom miniPCI driver says it's got 1300mW... but why 1300mW and not 3100mW? well, i have another theory beside thinking garbage values being returned..

1300mW is about 31dBm!!! and i dont see why wifi cards cannot have exactly that much of TX power. the FCC part 15 states that the limit for 2.4GHz non-channel-hopping radios is 1000mW (or 30dBm) provided it is attached to an antenna of 6dBi gain or less.... and for every 3dBi increase in antenna gain, the TX power has to be reduced by 1dBm. nothing further about the variations of radios+antennas configuration...

but here comes the creative thinking.. from there, one may deductively conclude that if the radio is permanently attached to a 3dbi antenna or less, then its maximum TX power can be legally increased to 31dBi!!!

i suspect that notebooks manufactures been doing this with their OEM wifi cards, especially with those miniPCIs, to keep their customers happy.... of course, those cards are not intended for desktop use, obviously, never to be sold as a part of a "highpower wardriving kit", or to be sold seperately at all, even if they are hard coded to a specific channel within the 2.4GHz spectrum

the wireless networking section at Frys, compared to other sections, has the most returned items from pissed off customer who bought brand-name wifi devices that put out 30mW... lol

cheers

Jeff Liebermann wrote:

Mine (USB ralink) didn't work with netstumbler. :-(

I opened mine up and yanked the antenna. I cut some hardline with a SMA on one end and plan on mating the two. It looks doable. [The idea is it is cheaper and better to use a USB cable to position the radio rather than have the loss in the coax.]

I also built a new biquad using what might be a time saving trick. Instead of trying to shove coax into copper pipe to do the feed, I cut the top (threaded part) off of a female to female N adapter with a hacksaw. Now I have N connector and a feed in one step. I cut a hole in the copper plate using a cheap ass Harbor Freight stepped drill bit. [The drill bit set is about the only good thing I ever bought there.]

I made the loop as a circle rather than having corners. Get copper wire and mark out two sequential segments 122mm in length. Don't start from the end, but give yourself some working room so you can grab the free end of the wire. I then wrapped the wire around a PVC adapter that was close to the proper diameter to get the shape. Then you bend the wire in the center to form one common point of the biquad loop. Trim the wire at the other marks and solder to the center feed of the hacked N to N adapter. Yeah, I'll get around to photographing this. Next up is fitting it to a Direct TV dish. [I couldn't find the Echo Star dish.]

did you install the driver on the CD that comes with the card? the updated driver seems not working well with netstumbler

i bought those airlink cards about a year ago and havent done any modification. i did pop the USB plastic case open and saw two antennas on this card. the external seems to be the TX and the one on PCB i think is the RX... it has different antenna configuration than its PCI counterpart, but the USB has a different chipset, the rt73 (vs rt61) which i suspect having better receive sensitivity

so the perfect mod would be replacing the external antenna with a reverse polarity SMA connector and hook it up with

a) yes, a very high gain omni or directional antenna b) or an external amp, like the popular and available hawking HSB2 that can put out 500mW and comes with a 2dBi omni

Frys is having HSB2 on sale for $69.... for antenna, i would look for one on eBay or other websites... i just can't stand the ridiculous prices that they set on those simple devices at local electronics retailers, even at Frys... despite the fact that i dont have enough skill and too lazy to build one

i am not sure how this set up would work for MIMO design, as the AWLL5025 specification says that it has diversity antenna configuration... meaning it assigns TX to one antenna and RX to another. This mod would probably improve just the TX side and leave the RX side at the mercy of the chipset's RX sensitivity

but the AWLH4030 is a different story. it has one single antenna for both TX and RX... so i removed the antenna and hooked it up to a hawking HSB1 (yeah i've got the version 1 of the HSB) set the amp to

500mW, snapped in a 9dbi omni and ran wildpackets omnipeek. From my 2nd floor apartment, i can see a wifi hotspot from a nearby scottish inn, which is about 1.5 miles away as the crow flies.... by the way, the setup is entirely indoor and done in my desk in the living room, and no, there's no clear line-of-sight to any of the networks i was able to "see" with this setup

contrary to popular beliefs, and politics, an external wifi amplifiers does boost the receiving side of the radio it hooks up to, provided that one single antenna is being used..... from my experience, the Hawking HSB1 and HSB2 are bi-directional, output 500mW of TX power and provide a +12dB RX gain, are relatively inexpensive and work well with both OFDM and DSSS in half-duplex mode ...

my next wifi adventure would be buying another HSB, hook them up in series, that would theoretically give me a +24dB boost in RX gain while maintaining the output TX power within legal limit... i cant wait to see how far my hotrod wifi toys can reach...

cheers

snipped-for-privacy@sushi.com wrote:

snipped-for-privacy@scn.org hath wroth:

The garbage values theory was what the developers at Wi-Fi Hopper responded with when I bug reported the problem. I've seen the same bogus power report with other boards and drivers.

I don't want to get into interpreting FCC 15.247. The maximum power output is 1 watt. Unfortunatly, they don't say where they measure this 1 watt. It could be at the transmitter, or at the antenna. Hard to tell. The common interpretation is 1 watt maximum at the antenna with a 6dBi omni antenna. If you lower the gain of the antenna, you cannot increase the power output to compensate. It would have made much more sense for the FCC to specific EIRP (Effective isotropic reference radiated power).

No. Or at least no according to several testing labs that submit FCC Part 15 type certification reports. Nice try.

Incidentally, if you really want high power in a laptop, see:

I like conspiracy theories but not this time. Linux utilities report the correct power output from the same cards that Windoze reports garbage.

That's one reason why I don't buy at Fry's.

Actually, what is returned at Fry's is handy to know. If there are lots of returns, try something else. I know those on this usenet group are Linksys fans, but most of what is returned to Fry's is Linksys.

If I think there are going to be problems with something, I always go to Fry's because they will take back anything.

I am running X64, so I had to get the driver off the net. I haven't tried the Airlink with netstumber on my notebook (win2kpro).

My understanding of diversity receive is there are multiple receive antennas and one combination transmit/receive antenna. On my SMC card, the combination TX/RX port is the one near the LED.

easy mate, interpreting the FCC, the IRS and the US Constitution shouldn't be that difficult

you see, a standard industrial spectrum analyzer, with proper input attennuator settings, hooked up directly to the RF transmitter at the connector will show exactly the TX power of the device. Simple as that!

now, suppose the measure of TX power is at the transmitting antenna, then of course there's another setup and calculation for the spectrum analyzer to do just that, but it begs the questions

1) how far away from the transmitter should the spectrum analyzer be positioned? 0 feet? 1 feet? 3 feet? 10 feet? 10 miles? 2) what is the standard for the field-probing antenna? loop? yagi? omni? what about its sensitivity? 3) if the probing antenna is to be right at the transmitting antenna, then what part of the transmitting antenna should it touches? the head? the tail? the middle? the center? the rim? at what angle?

sounds like the things only a clown would do in a circus, eh?

oh and why not buy at Fry's?..... like, the things you buy from the store would fry themselves... or what? just kidding

Jeff Liebermann wrote:

snipped-for-privacy@scn.org hath wroth:

True. It shouldn't, but it is. I've been dealing with the FCC on and off since about 1968. These days, rules-n-regs are scribbled by attorneys, not engineers. I'll spare you my list of horror stories over the years.

Nope. Quiz time:

You have a spectrum analyzer that shows an 802.11g spread spectrum signal that is approximately 25Mhz wide. Peak power on the scale is

0dBm to make the calculations easy. The spectrum analyzer IF bandwidth is 500KHz. What is the "real" power (ignoring duty cycle)?

I'll supply the answer tomorrow. Note that this is not a trick question and the numbers are quite real.

What question? The FCC is usually very clear where to measure things. They missed this time. However, I've learned from bitter experience to NEVER ask the FCC for clarification, because I've always gotten the answer I least expect, and often with unpredictable side effects.

You're measuring power output, not field strength. If you want to measure RF field strength, there are some rather simple guidelines intended to keep your spectrum analyzer out of the near field and only pickup the far field. The only time the distance needs to be specified for the test is when measuring incidentally radiation. For field strength, anything resembling a calibrated antenna will work to calculate the field strength.

The type certification, they're rather specific in what may be used. Go to the FCC ID web pile and pick any likely FCC ID number for a wireless device. The applicants are required to supply photographs of their test setup, which includes the test antennas.

It's not.

None. Look at the photos on the FCC ID web pile. They have to be far enough from the unit under test to not be considered within the near field.

Ummm.... I'm one of those clown. Thanks for sharing. Bye.

I would say that's hard to judge. In the WiFi sections (more than one, since there are some dedicated sections, including Linksys), there are many empty shelf spaces, usually for the item you want, plenty of items in the wrong shelf space, and some opened/returned/markdown units, with markdowns of 12-15 cents, which fascinates me.

I would guess that they don't give Linksys their own dedicated space unless they move lots of units, so the number of returns on the shelf would have to be noted against the number sold.

Wifi is still an emerging market. Many of the units are purchased with unreasonable hopes, like using Wifi while commuting on Caltrain... okay, so that works now; or getting free access anywhere, or full coverage in a home. Those units probably come back, maybe for refund, maybe to exchange for a different brand.

The motherboard section is full of returns, often with no new units on the shelf. For stores other than Sunnyvale, I don't know what that means, but in Sunnyvale, I have overheard engineers selecting motherboards to take back and test/certify against some product or another, after which it will be returned to Fry's. But these are the same guys trying to make sure they get one that is unopened.

The home of the thirty day free trial for almost anything. I have seen people return stereos with no packaging.

i played with the linksys WRT54G for a while and somehow got stuck in DD-WRT concept of diversity antenna. and also i am skeptical about the MIMO title that the Ralink chipset is advertised, after all, the AWLL5025 is still within 802.11G specs, while MIMO seems to belong to draft-N or whatever...

but yeah in true MIMO design, diversity mean multiple RX antennas, (and mulltiple TX antennas too) i often see draft-N wireless adpaters with three antennas, just like the 802.11G AWLH5025 PCI adapter, but i was too lazy to learn about the antenna configurations. let me give it a try. these are possible configuration in a three-antenna setup

a) three TX/RX combos b) one dedicated RX and two TX/RX combos c) one dedicated TX and two TX/RX combos d) two dedicated RX and one TX/RX combos e) two dedicated TX and one TX/RX combos

i am still clueless about how many radios needed for one "draft-N" adaptor. but i do hope that there's no final N. 802.11 B/G is good enough for me, and for all, that's all we need for wireless internet.... as for networking, i'd prefer and recommend the old fashion way...

anyways, in the case of the AWLL5025 USB, the external antenna must be the combo TX/RX. Thank you for pointing that out. it makes alot of sense... and i think i am gonna hack the antenna after this... yes i am serious!

cheers

snipped-for-privacy@sushi.com wrote:

Diversity as receive only has been around for some time. Military of course, but some high end automobiles had diversity receivers for their FM broadcast reception.

I can understand diversity receive. The receiver comes up with some sort of figure of merit on the reception. It is multiple transmit (output) that confuses me. I don't see how a transmitter decides which antenna to use. In any event, if everyone had diversity in the receive path, I don't see why it would be needed in the transmitter.

is the high power card I use in my notebook. It has diversity receive, but one transmitter. They claim half a mile on the detachable antenna. Hardly. However, I've done drive-bys of at least a mile with the biquad. Make that the bad biquad, i.e. the two wire instead of the coaxial feed. I haven't tried the good biquad over any distance yet.

This is what Jeff considers the good biquad:

I used something like this for the feed: Typically they are smooth, not knurled. [Should be about a dollar at the ham flea market.] Hacksaw one end off, leaving the center pin exposed. Then position the adapter so you get the right distance between the antenna and reflector. I cut the copper plate, drilled the hole, then tinned the area around the hole with solder. This made it easier to solder the N adapter to the copper plate. You need a propane torch. [Benzomatic]

snipped-for-privacy@scn.org hath wroth:

Correct. The marketting baloney that accompanies the Buffalo WHR-HP-54G is disgusting. They use the term MIMO because it's the latest and greatest, while there's nothing even remotely related to MIMO inside the box. What Buffalo is pushing is that you'll get the same performance as MIMO with their high power transmitter, and offer some un-reproduceable tests to prove it. It makes me sick to see a good product polluted by such technically inept marketing.

MIMO is not diversity. What "real" MIMO does is send data from 2 or more antennas. The data arrives at corresponding antennas and receivers, but delayed very slightly. The DSP is able to seperate out the various delays and extract seperate data streams for each delay. The result is a doubling in available bandwidth. See:

There's also a skool of thought that claims that MIMO is also adaptive antenna patterns. This is where the access point contains a smart antenna system that adds more gain where it's needed, and installs nulls where it detects interference. See Ruckus Beamflex at:

I have a good laugh on this one. The system works, but Netgear advertises their various routers mounted in the vertical (tower) position, where the beam forming can't work.

If you're interested in reading about non-MIMO diversity reception see: