wireless network adaptors: long range
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Posted by net on May 22, 2008, 7:04 pm
Please log in for more thread options occurrs to me there must be something better than the long-range pci and pcmcia cards I've seen for sale. Is there such a device or are we all stuck with these cards? I know about yagi antennas and such and I know the antenna is important for range and power but I wanted to start with the transmitter/reciever first and see what the best thing around was. I'm interested in fixed location equipment, I don't need mobility. Thanks for any pointers. | |||||||||||||
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Posted by Paul on May 23, 2008, 6:33 am
Please log in for more thread options Something you should investigate, before going further, is the FCC (or your local equivalent thereof), has rules for both unlicensed and licensed uses of the airwaves. That means, I cannot emit more than a certain power level, on my RF transmitter, unless I want to get in trouble. The rules are there, to allow the multiple users of these services, to all play together. http://www.ddj.com/architect/184411700 If you use a wireless product, complete with original antenna, then you can be sure you're staying within the rules. That would be a PCI card with the antenna that came with the product, or a PCMCIA card with the antenna that came with the product. Not with an amplifier strapped to the thing, or large high gain antenna. The FCC may not be driving around in a truck, looking for trouble-makers. They'll instead be triggered by complaints. Say, for example, a local cellphone operator, is suffering service outages in your neighborhood. The FCC man comes to investigate, finds the offending transmitted frequencies, uses a few antenna trucks to triangulate the source. Then you get the knock on the door. I can give you a more concrete example. In my city, one day, all the garage door openers that operate on a certain RF frequency, stopped working. (Some people couldn't get their garage door open.) It was discovered, that a powerful transmitter was operating in the city. (One theory was, it was located on the roof of a certain embassy!) It took several days, before the problem "went away", without any details being released to the press about the offender. So, if there is an offense, like illegal power levels, used on an RF device, finding and tarring the individual takes time. If you want to read some amusing articles on Wifi and distance, try world's record wifi http://www.engadget.com/2007/06/19/venezuelans-set-new-wifi-distance-record-237-miles http://www.dailywireless.org/2003/01/06/worlds-longest-wi-fi-connection/ I think I read an article in the past, about one of those mountain to mountain project, which went into some details, about things like whether the time constants in the standard protocol, allowed distances like that or not. And you can see in that picture, that they're using a pretty fancy high gain antenna. HTH, Paul | |||||||||||||
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Posted by LR on May 23, 2008, 7:52 am
Please log in for more thread options Paul wrote:
> net wrote:
>> in aiming for the highest powered wireless device for a desktop pc it
>> occurrs to me there must be something better than the long-range pci and >> pcmcia cards I've seen for sale. Is there such a device or are we all >> stuck >> with these cards? I know about yagi antennas and such and I know the >> antenna >> is important for range and power but I wanted to start with the >> transmitter/reciever first and see what the best thing around was. I'm >> interested in fixed location equipment, I don't need mobility. Thanks for >> any pointers. >> >
> Something you should investigate, before going further, is the FCC > (or your local equivalent thereof), has rules for both unlicensed and > licensed uses of the airwaves. That means, I cannot emit more than > a certain power level, on my RF transmitter, unless I want to get > in trouble. The rules are there, to allow the multiple users of these > services, to all play together. 8>< Zen.co.uk? From 2004 <http://www.ofcom.org.uk/radiocomms/ifi/licensing/classes/rlans/technical/wireless.pdf>
2006
<http://www.ofcom.org.uk/consult/condocs/powerlimits/statement/statement.pdf>
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Posted by kony on May 23, 2008, 11:24 am
Please log in for more thread options On Fri, 23 May 2008 00:04:10 +0100, "net"
>in aiming for the highest powered wireless device for a desktop pc it
>occurrs to me there must be something better than the long-range pci and >pcmcia cards I've seen for sale. Is there such a device or are we all stuck >with these cards? I know about yagi antennas and such and I know the antenna >is important for range and power but I wanted to start with the >transmitter/reciever first and see what the best thing around was. I'm >interested in fixed location equipment, I don't need mobility. Thanks for >any pointers. You may have better range with a mimo or 802.11n (external) router operating in bridge mode, but of course having it external is simply to allow better placement and aiming of the antenna without the inherant loss of a longer RF connecting cable to the antenna(e). You wrote highest powered though and Paul already covered the issue there. They are set up with inbuilt power limits to make them legal for sale to unlicensed customers, as equipped (w/original antenna). A better question is what is your specific need for this equipment? In a fixed location there are more options than only trying to get from one client to (whatever the other end is, server or router or client or ...), for example running some ethernet cable to an access point nearer the system, or if you're trying to bridge a greater distance outside you would want to mount an antenna on the roof, higher up, again with a bridge config at the antenna so you have negligible cable loss. If your needs are more simple, the basic thing to avoid doing is having the PCI card blocked by that large hunk of metal that is a system case. Get (whatever) any product that has the antenna away from the case and in difficult areas that is directional and aimed at the other end (while checking signal strength report from computer). If you can find reviews on whatever you're considering, so much the better, it is often a buyers market so what you end up with could reasonably be determined by the sales available at the time unless the environment is difficult enough you will need enterprise rather than consumer grade gear. | |||||||||||||
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Posted by tg on May 25, 2008, 9:18 am
Please log in for more thread options
> On Fri, 23 May 2008 00:04:10 +0100, "net"
> > > You may have better range with a mimo or 802.11n (external) > router operating in bridge mode, but of course having it > external is simply to allow better placement and aiming of > the antenna without the inherant loss of a longer RF > connecting cable to the antenna(e). <snip> okay thanks for your help kony. I think based on what you said a long range PCI card with external antenna is the best place to start. | |||||||||||||
> occurrs to me there must be something better than the long-range pci and
> pcmcia cards I've seen for sale. Is there such a device or are we all stuck
> with these cards? I know about yagi antennas and such and I know the antenna
> is important for range and power but I wanted to start with the
> transmitter/reciever first and see what the best thing around was. I'm
> interested in fixed location equipment, I don't need mobility. Thanks for
> any pointers.
>