LoneStar

A neighbor is letting me borrow a Wireless USB 802.11b client. It appears to be the same one that is made by Gigafast. The one I have says prairieinet on the front. As an 802.11b client it works very well. It is housed inside of a shielded case and it has an external antenna that uses an SMA connector.

The microchip that is doing all the work is an ATMEL AT76C503A. The drivers that came with the device are for Windows 95, 98 and ME. I installed them on Windows XP and I have had no difficulty.

I searched the Internet for a newer XP driver and I thought that I had found one, but it was on a password protected webpage. I called Gigafast to inquire about an XP driver. I reached a person that could not speak English very well at all. He told me, "Use old driver. Make you frown. XP buggy." I translated that to mean that the older driver will work best and that the newer driver for XP is so "buggy" that it will make you so sad that you will frown.

Now here is the INTERESTING part. There is some included software for configuring the wireless device. One tab says, "Site Survey." It shows a list of available networks. Including networks that are not broadcasting their SSID.

The device will not work with Network Stumbler, but my interest in this is growing. Is there anyone out there that has any experience with the Gigafast or Prairieinet "Wireless LAN USB Dongle?"

Attached Images

atmel wireless lan monitor utility - site survey.jpg (26.2 KB, 313 views)

LoneStar

A photo of the front of the device.

Attached Images

amtel_t.jpg (8.5 KB, 309 views)

Thorn

PrairieInet is a WISP (aka Wireless ISP) in Iowa, Illinois, Nebraska and Kansas. It would appear that they are using the Gigfast unit as a CPE (Customer Premise Equipment.)

A fair amount of hardware makers include "Site Survey" application software with the device. Usually it places the unit in an SSID of "ANY" config, so you can see who is near, and avoid their channel(s).

Hope this helps, and doesn't "Make you frown."

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Thorn
"Read Altas Shrugged. Compare it to today. Repeat as necessary"

LoneStar

Yes. I'm sure that Prairieinet either used or had planned to use these for that purpose. Evidently these devices were purchased as surplus.

I've attached another image to this post. I think it better illustrates the number of wireless networks in an area that are not broadcasting their SSID. None of these are detected with Network Stumbler.

BTW, attached to a 1 watt amplifer/preamp this thing can detect networks at an incredible distance.

Attached Images

covlakesidegarage1.jpg (40.7 KB, 305 views)

Thorn

Ouch.

I hope you know the proper use of a 1W amp. Please tell me you're not putting amped output into a a high gain omni antenna. Amps for 2.4GHz aren't really made for that, and are generally a bad idea.

Be warned. It may be exceeding the legal limits by a large amount.

You could be blasting too high a signal over the whole area and potentially causing problems for everyone else running 802.11b gear in the area.

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Thorn
"Read Altas Shrugged. Compare it to today. Repeat as necessary"

LoneStar

I am using a Winncom WAF2400 amplifier. It is specifically designed for data in the 2.4 GHz band. I promise that when using Network Stumbler I am not creating any noticible interference to anyone's 802.11b.

Now when I use the Down East Microwave amplifier to increase my 2.4 GHz video transmissions I'm sure that some 802.11b users in my area do get interference. However, I haven't received any complaints.

Remember that 802.11b must follow Part 15 of the FCC rules.

Wintermute

legal limit is 100mw my fellow stumbler.

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802.11b is teh $hit.

pmn929

But then again is it?

There are legal ways to increase your power to 100w... At least on channels 1-8... Although I wouldn't recommend going that high.

Thorn

LoneStar, if you referring to the "must acccept any and all interference" clause, my understanding is that applies to legal interference. i.e. interfence that is produced by devices that at radiating within their set legal limts. If you should exceed the legal limit and a complaint is filed, then you're fair game for the FCC.

I understand that Winncom, and other manufacturers make 2.4GHz amps for the data market. When I said "Amps for 2.4GHz aren't really made for that, and are generally a bad idea." I meant they are made more for the WISP market, and aren't really made for general use. I should have made that a bit clearer.

Quite frankly I don't know what the 2.4GHz power limits are for unlicensed video devices, but I can't imagine they go very high either.

BTW, I'm not presuming that your setup is illegal. I'm just saying that from the info in your prior posting, you might be close, and you should CYA. If you know how to use this stuff properly, great! I just hate to see people get in trouble because they think "unlicensed = unregulated." I also don't like the thought of someone blasting their neighbors' signals out of the water because of ignorance or illegal use.

The unlicensed use, legal limits for 802.11b aren't quite that simple. It is actually 30dB (1 Watt) effective radiated power for a Point-to-MultiPoint (PtMP) transmission, and 36dB (4 Watts) for a Point-to-Point (PtP). Effective radiated power is the output seen at the antenna.

To calculated the power output, take the final output from the devices, such as the AP or AP and amp, subtact any line losses from the coax and connectors, and add the gain of the antenna. To illustrate: Assuming for argument's sake a 1 Watt (30dB) amp, a 2dB line loss and a 5dB omni. (30 - 2) + 5 = 33 dB (2 Watts) output. Clearly illegal for anything but a PtP setup. To be legal with this antenna combination, you would need to have no more that a 27 dB (.5 Watt) amp. (27 - 2) + 5 = 30.

BTW, these power limits are for general public unlicensed use for 802.11b. Amatuer (ham) also use the 2.4Ghz area, and the hams have different power output limitations. However, hams can't use this for any business purposes.

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Thorn
"Read Altas Shrugged. Compare it to today. Repeat as necessary"

LoneStar

Yes. I am an amateur radio operator and much of the equipment that I use I have constructed myself. On my own wireless network I use the equivalent of 802.11b's channel 1 which is 100% within the primary ham radio band. It's even designated by the ARRL for high-speed data.

Actually hams can conduct some business using the amateur radio service frequencies. For example, if I wanted to order an antenna from Fab-Corp over the Internet and I was accessing the Internet using amateur radio, then this would be legal. It would fall under the same guidelines as the famous "Pizza Ruling" that allows an amateur radio operator to order a pizza through a radio phone patch. What would be illegal is for me to sell stuff on eBay using my wireless network.

BTW. I have setup my network so that other ham radio operators in my neighborhood can gain access to it.

Right now the experimental allocation in the 2.4 GHz band is home to 802.11b, Bluetooth, cordless phones, baby monitors, video transmitters, home security systems microwave powered energy saving light bulbs and lots more Part 15 devices. As this market grows even more you can expect to get interference from these devices on your wireless networks. Don't expect my properly installed wireless setup with the 1 watt amplifier to ever generate noticible interference to an 802.11b network.

You could easily put a dozen 802.11b devices using spread spectrum in close proximity and never notice a significant amount of interference. Even if they were tranmitting a clean 1 watt signal.

Have a nice day.

LoneStar

In the Amateur Radio Service, spread spectrum power limit is 100 watts and any power 1 watt must automatically adjusted so that it meets certain requirements.

The Rules:
(d) The transmitter power must not exceed 100 W under any circumstances. If more than 1 W is used, automatic transmitter control shall limit output power to that which is required for the communication. This shall be determined by the use of the ratio, measured at the receiver, of the received energy per user data bit (Eb) to the sum of the received power spectral densities of noise (N0) and co-channel interference (I0). Average transmitter power over 1 W shall be automatically adjusted to maintain an Eb/(N0 + I0) ratio of no more than 23 dB at the intended receiver.

ZenOps

I'm beginning to see why an amp and an omni really dont mix well.

The FCC PTMP maximum, which is what an omni is used for is 30dB.

Out of the air example:

If I were to hookup a Cisco aironet (20 dB) to a 19 inch LMR 100 cable (about 2db loss) and a 12 dbi gain omnidirectional antenna, would that put me right at the legal max?

Thorn

Yes. (20 - 2) + 12 = 30

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Thorn
"Read Altas Shrugged. Compare it to today. Repeat as necessary"