Greetings All,
I've had fo some time an Orinoco Wave Lan II Access point in my home and have now decided I need better range. I haven't started Stumbling around town yet but I know The university of Kentucky has a system and it has decent coverage. However, I'm looking at increasing the range of my system.

I like Fab-Corps products and am now happy about possible discounts, after joining Netstumbler.
Here's my question(s).

1. By going with the 15 dB omni amp on their site, and the 1 Watt smart amp, as well as the 5 dB mag mount antenna for the car and the portable, and using my Orinoco Silver cards, both in the AP and the laptop What kind of range are we looking at. Anyone used this setup?

2. Monitoring my AP I have noticed a high number of errors On the AP from the wireless side, even when I don't have any of my wireless cards running on any other device. I do however have a Siemens 2.4Ghz phone system with multiple remote phones. Could this system be confusing the AP because it throws out rotating frequencys on a regular basis? Any Clues?

Thanks and I can see this is going to be fun. :-)
Joe.

You may want to review the FCC regs before you go setting up something that so clearly violates them. Then you cannot claim ignorance when they send you a letter threatening fines in the $10,000 USD plus area.

Thanks Don,
I had almost began to believe that this was helpful forum. Where the curious might ask a question, and get some useful information. But, your answer makes me feel certain my overwhelming loathing of public forums is truly justified.

Not only did you not answer either question, you failed to site FCC regulation regarding the limitations on the 2.4Ghz band. You may have given some regulation number or or possible statute number but I feel certain that your intention was to simply be "Scary" with the threat of a $10,000 fine.

Thanks again.
Joe

Hey Joe, don't be too hastly... You'll just get flamed if you start in with the attitude on your second post. Maybe DonChicago did not answer to your satisfaction, but it doesn't mean it was devoid of information.

To answer your questions, and add some detail:

1)The base setup that you describe is illegal. Here's why:

The FCC regs are in Part 15, which is rather long and involved. If you want the full details, the FCC does make it available on their website. I can quickly summerize the section which you are interested in however. The maximum gain for the 2.4GHz ISM band (which 802.11b this stuff is in) is 36db for a "Point To Multi-Point" design. This is what you are describing. A PTMP is a base-to-mobile or base-to-multiple-bases setup. A "Point To Point" design can radiate an u to 48db gain. A PTP is two dishes or similar antennae pointed directly at each other, with no other systems receiving signals between them. This is mainly for long distance links.

Now, your next logical question is "What is my gain with the setup I described?" Here's the equation: 1 watt = 30db, so 30db + 15db (gain of antenna) = 45db. Clearly over the limit for a PTP setup. To be legal with a 15db antenna, you could have no more than a 21db amp, or about .7 watts. (The db is a logirithmic scale, so that's not quite right, but close enough for explanation purposes.)

Stick with a 6db gain attenna or lower, and you would be legal. You may compute line losses here if you are using a long coax feed, but I'm keeping this example simple, and assuming a short coax with a negligible loss. To do the actual computation, you would have to know the length of the coax, and its db loss per a given length. Cable manufacturers post this info.

A couple of further thoughts about amps. First, they are expensive. Second, by their very nature, amplifiers will amplify the NOISE as well as the SIGNAL. So if you have a noisy setup, is effectly just "louder." You will kill six or more channels from being usable, unless you add some sort of side band filter. Most professional installers shy away from them unless absolutely needed. You might want to do a site survey without an amp before spending the money. Third, this is RF radiation. At the low levels that you are dealing with from a card, you don't really have too much of a problem. But when you boost it via amps and antenna, you are approaching an area where you *might* have adverse health effects, if you set this stuff up incorrectly. Just be careful. My advice is to stay away from amps until you know what you are doing with them. By the very nature of the question you are showing that you need to do some more research first.

2) 2.4Gz phones can and do cause interfence. They are in the same band. So do wireless video cameras (X10's for instance) and many microwave ovens, and other 2.4GHz radiating devices. So your phones could be a problem, but think of other potential sources too.

As to ChicagoDon's "scary threat" of a $10k fine, well, that is the standard figure that the FCC usually credited with hitting people with. I believe provisions for fines are also listed in Part 15. The FCC usually deals with commerical broadcast stations, so big fines are the norm there. If you made the stupid mistake of intentionally violating the regs, and were caught, most likely the FCC would order a "siese and desist" order, and if you still didn't comply, then seize the equipment. But they COULD hit you with a huge fine, and there is no requirement that I know of that they issue a warning first. Just make an intellient decision knowing all the facts. If you do decide to intentionally violate the law, you can't say "But no one told me." And if you knock out someone else's setup in your neighborhood by being illegally overpowered , the FCC is who they complain to.

A couple of other things to consider: It has been reported in the trades that the FCC has doubled the enforcement budget this year. And those same trades say they are reportedly very interested in 802.11b.

One final word, read through these forums and use the search function. This has been asked and answered before, in differing amounts of detail. Other postings might give you some more food for thought.

Cheers,
Thorn

Joe you are on the right track to figure out the range thing....I have a nearby outdoor system at a yacht club, using 3 sector amplified antennas driven by Buffalo (residential) access points....I will be testing shortly using Orinoco card and Fab-Corp. 5 dBi mag antenna; will also get details on amps they are using

as for the FCC, i would guess they'd have rules on stuff like not-to-exceed saturation flux density for amplified, unlicensed 802.11; obviously the power and proximity of abundant unlicensed 802.11 is Sirius' big concern for interference with their expensive licensed satellite radio service

so the FCC is likely to have metrics like SFD with to regulate the unlicensed bands; although it may be difficult for you to determine the SFD of an amplified system without the right measurement devices, you can probably estimate your system's power using formulas taking wattage, antenna gain, etc. into account....the wireless consulting guys do this stuff for breakfast (usually for a fee, of course)

Greetings All,
While I admit to being hasty with my sarcastic reply to DonChicago, I do want to thank those that have replied especailly Thorn.
While I had read all the information I could find on the FCC site including all parts relating to 2.4Ghz I could find, I did not have a clear understanding of the limitations. Nor did endless reading of the FCC regulations clarify it.

After even further research, I noticed that the one Watt amp has a 17db gain on the RX side and a 30db on the TX side. That of course would put me way over the limit, thanks to my new understanding.

Let me change the senario a bit. To see if I now have a better understanding.

In order to effect a long distance point to multipoint I could in fact use with no legal FCC wrangling an 8dB omnidirectional outdoor antenna and Fab-Corps 500mw amp that has a 27db gain on the TX and a 17dB typical on the RX. While I'm sure I would be skirting the limits, would this be considered "Okay" by the FCC. I already have an antenna tower at about 75 feet. So RF radiation is at a minimum to the immediate neighborhood.

Due to some other activities I am involved in I have dealt with the "New and Improved" FCC. While it will take a while for things to shake out they'll eventually be a threat to those stepping over the line. The days of Pirate Radio are numbered and it's sad.

Later and Thanks again.

Joe,
You're welcome.

The setup you describe sounds good. It would seem to put you at 35db, and if there is any line loss, actually a bit lower. But boy, with a 75 ft tower are you sure you need an amp? (I'd kill for that size tower. We have heavy zoning against such things where I live.)

Next step, you have figure your Frensel limit... I think www.ydi.com has a nice online calculator for Frensel. We'll make a skunkworks RF engineer out of you, yet. :-)

Cheers,
Thorn

nuc all lowlansrs...

21dB actually works out to about .5 watts, not .7 watts, and the spelling is "Fresnel" not "Frensel." Geez, I guess I should re-read what I type. Either that and type when I'm awake. :-)

Greetings Again,

I had one other concern about this type of set up and when looking at the Fresnel I'm curious if I should worry about getting an omni directional antenna with a down turn. With the Antenna being 75 feet in the air I was thinking I may create a Black hole here at the house and the wireless stuff will have problems in the immediate area if the antenna doesn't have a down turn on it to cover below the antenna with a bit of signal. Just thinking.

I know the practical fix for this in my situation, which is to slap a second wireless card in the Wave Lan AP and that would give me immediate coverage in the house with no problems. The outdoor omni antenna could feed from one and the immediate local stuff could feed from the other.

Thanks again to all for ideas suggestions and references. This is shaping up to be great fun.
Later
Joe

Hi Joe,
Yeah, you'll probably have a "black hole" by virtue of the antenna that high over the house.

Look at the radiation patterns of the antenna you're buying, and it may give some indication. Most of the manufactures will have them posted. For a good sampling, I like <a href="http://www.superpass.com" target="_new">Superpass</a>. They're a good company to deal with, make nice units and are reasonably priced.

A second card will cure the immediate problem. Just keep the cards on a non-overlapping channels (1, 6, and 11) and don't forget roaming. You may need to implement it on your model of AP, so you can move between the channels. To get the best receprtion for you setup you might want to have the AP mounted midway on the tower in a NEMA rated box, and have the "long range" antenna at the top for distance and the "local" antenna mounted down closer to ground level. You may still have an area where you are between the two signals, but it would probalby pretty small.

If you get this functioning, post some info on a web page, so we can all see it.

Cheers,
Thorn