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Help with Wifi antenna
Please see subject line-- Help, Wifi Antenna-- on
alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike |
Help with Wifi antenna
amdx wrote:
alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. With a 100mW source and a reasonablyshort cable the famous Pringles can antenna would be illegal for mobile/portable use and probably illegal for fixed links. It happened to be developed by an FBI agent in the process of an investigation, so he was covered, you may not be. Here in Israel it is limited to 100mw EIRP, so unless you have a very long cable, any gain antenna would be illegal. Someone wrote up (in Hebrew) and posted on a web site his use of a similar antenna. It's not obvious to the casual reader that he did it in an area under the jursidiction of the IDF (Israeli Army) and got permission from them. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838 Visit my 'blog at http://geoffstechno.livejournal.com/ |
Help with Wifi antenna
"amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike Hi Mike You sure find some great information on the Web. I consider this article Jason Hecker publishes http://www.wlan.org.uk/jhecker.html to be ALL the instructions anyone would need for constructing a 20 dB directivity WiFi antenna. I am looking for some feedback from you on its performance. If you plan to investigate basic effects of changing size and shape of Helix antennas, EZNEC sure makes Helix antenna investigation easy. I am just curious, what kind of coax and connectors are you using, and, ?how much coax?. Jerry |
Help with Wifi antenna
Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Jeff |
Help with Wifi antenna
On Wed, 25 Jul 2007 18:12:26 +0100, Jeff wrote:
Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Oh , really ?! cite! |
Help with Wifi antenna
Jeff wrote:
Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Only 802.11b/g channels 1-6 fall in the amateur allocation of 2390-2450 MHz. If operating under amateur regulations you must identify by CW, phone, RTTY or TV image every 10 minutes or less (see 47CFR97.119), your transmissions must be intended for reception by another licensed amateur station or station authorized to communicate with amateur stations (see 47CFR97.111), that has to be the only reasonable way to effectively communicate, no other radio service available that accomplishes the same communications (see 47CFR97.113) and you have to use the lowest power level capable of accomplishing the communications (see 47CFR97.313). See http://www.access.gpo.gov/nara/cfr/w...7cfr97_01.html for specific regulations. |
Help with Wifi antenna
gwatts wrote:
Jeff wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Only 802.11b/g channels 1-6 fall in the amateur allocation of 2390-2450 MHz. If operating under amateur regulations you must identify by CW, phone, RTTY or TV image every 10 minutes or less (see 47CFR97.119), your transmissions must be intended for reception by another licensed amateur station or station authorized to communicate with amateur stations (see 47CFR97.111), that has to be the only reasonable way to effectively communicate, no other radio service available that accomplishes the same communications (see 47CFR97.113) and you have to use the lowest power level capable of accomplishing the communications (see 47CFR97.313). See http://www.access.gpo.gov/nara/cfr/w...7cfr97_01.html for specific regulations. I forgot to mention amateur communications cannot be encrypted, so no https, see 47CFR97.113 again. |
Help with Wifi antenna
That may be true but to use it that way legally you would need an
amateur license, and this is not just a paperwork exercise, you have to pass FCC exams covering electronics and radio theory (plus laws and regulations) to get one. For most people, it's not an option. Allodoxaphobia wrote: On Wed, 25 Jul 2007 18:12:26 +0100, Jeff wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Oh , really ?! cite! |
Help with Wifi antenna
"gwatts" wrote in message
... If operating under amateur regulations you must identify by CW, phone, RTTY or TV image every 10 minutes or less (see 47CFR97.119) Most amateurs set the SSID of the access point to their call sign, since this is beaconed numerous times per minute. Apparently that's close enough to RTTY to keep most people happy. your transmissions must be intended for reception by another licensed amateur station or station authorized to communicate with amateur stations (see 47CFR97.111) Sure. that has to be the only reasonable way to effectively communicate, no other radio service available that accomplishes the same communications (see 47CFR97.113) This particular regulation creates plenty of argument, since realistically the vast majority of activity on amateur radio frequencies these days could be just as readily accomodated by either cell phones or the Internet; I doubt the FCC has cited anyone for violating this rule for decades now. and you have to use the lowest power level capable of accomplishing the communications (see 47CFR97.313). Indeed, although this too is subject to debate because people will argue that while, e.g., 1W will get them a bit error rate of 10%, they "need" a near-zero bit errorr rate and therefore transmit at 100W. You point about not being able to use HTTPS or other encrypted protocols is probably the most significant change in moving from using WiFi in an unlicensed mode to using it under the amateur radio service's rules. However, note that it is perfectly OK to obfuscate *authentication* data such as passwords -- packet BBSes have done this for decades. ---Joel |
Help with Wifi antenna
"Barry Watzman" wrote in message
... That may be true but to use it that way legally you would need an amateur license, and this is not just a paperwork exercise, you have to pass FCC exams covering electronics and radio theory (plus laws and regulations) to get one. For most people, it's not an option. Very few people would have significnat difficulty passing the technician class license exam that's needed to operate on 2.4GHz. Indeed, there are many month-long (meet a couple times a week) classes and even weekend "cram" classes that have near 100% success rates in getting people their tickets. A passing score is 80%! |
Help with Wifi antenna
"Jerry Martes" wrote in message news:KGKpi.5345$Da.3887@trnddc07... "amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike Hi Mike You sure find some great information on the Web. I consider this article Jason Hecker publishes http://www.wlan.org.uk/jhecker.html to be ALL the instructions anyone would need for constructing a 20 dB directivity WiFi antenna. I am looking for some feedback from you on its performance. If you plan to investigate basic effects of changing size and shape of Helix antennas, EZNEC sure makes Helix antenna investigation easy. I am just curious, what kind of coax and connectors are you using, and, ?how much coax?. Jerry Hi Jerry, Please review the picture I posted on alt.binaires.schematics.electronic in it you will see I'm trying to avoid connectors and cable carrying 2.4Ghz R.F. Thanks for being the only poster to have anything near a response to my post. Mike |
Help with Wifi antenna
"Jeff" wrote in
. com: Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Jeff Not in most civilized countries. 2.4 Ghz is unlicensed, not unregulated. |
Help with Wifi antenna
On 7/25/07 10:12 AM, in article
, "Jeff" wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Jeff Hams have a segment of it, but not 2.4 to 2.5. However, if the wifi ends up in the ham band in a commercial purpose there will be hell to pay when they get caught, ham or not. |
Help with Wifi antenna
Jeff wrote:
Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Jeff Well.. not all the 802.11b/g channels are in the amateur band, and even there, there is a power limit (transmitter output power, though, not EIRP), so you could conceivably fire up your 1500 Watt transmitter into a 20dBi antenna and blast away. There is the other rule about minimum power needed for communication, though. |
Help with Wifi antenna
"mike" writes:
Hi Jerry, Please review the picture I posted on alt.binaires.schematics.electronic in it you will see I'm trying to avoid connectors and cable carrying 2.4Ghz R.F. Thanks for being the only poster to have anything near a response to my post. Do note that many people's Usenet servers do not carry any binaries groups, so they will be unable to look at your picture. If you were to place the photo on a server where it can be accessed by HTTP or FTP, these people would be able to get it. Many ISPs provide some web space served by their own web server, and there are free photo hosting sites like flickr. Dave |
Help with Wifi antenna
"amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike The Wifi Helical antenna is an awful lot of work, and the performance of even long structures on PVC tubing is vastly disappointing. The easiest 15 dBi (my measurement) gain antenna is the Biquad. In fact, if you make the biquad with circular instead of square loops, the construction is even easier, and there's no problem measuring with all those bends - - just one wavelength of straight wire in a circular loop for each section - - http://www.wikarekare.org/Antenna/bicircle.html But try to keep a 50-ohm coaxial configuration all the way to the feed points as in http://homepages.ihug.co.nz/~redwood4/ It isn't necessary to keep the polyethylene insulation - - for a short length of air insulated coax, the tubing ID should be 2.25 times the center conductor OD for 50 ohms impedance. If you are like me, you will probably want to build the Helical anyway - - just to see, and perhaps to compare against the two easiest wifi antennas with decent performance - Biquad and Waveguide http://www.saunalahti.fi/elepal/antenna2.html The easiest waveguide can is the 83mm ID one you get with the 28oz size of Bush's Baked Beans or any of a number of other products like canned spaghetti sauce or family size Spaghettis. See if you can get a USB Wi-Spy Spectrum Analyzer module, too - - try to find one of the original (no external antenna - - cheaper) versions, and just put it in your own shielding enclosure and make your own modification to cut the path to the built-in antenna so that you can run a small coax to a connector on the box for your own external antenna connection. This kind of modification has been made by others - - http://www.metageek.net/default.aspx...5&view =topic scroll down to the post by pe2er on 9/9/06 showing how to connect a coax to the board. I used a type N connector on my enclosure because it's universal and strong, and filtered the three USB supply and signal wires with feed-thru capacitors so no RF can enter the enclosure through these other paths. Use Metageek.'s Chanalyzer software to run the Wi-Spy module - - preferably version 2.0 before the current 2.1.4 came out, since the need for compatibility with both the $199 Wi-Spy and the $399 Wi-Spy made operation with the $199 Wi-Spy somewhat unsatisfactory. Maybe you can ask Metageek to allow access to previous Chanalyzer 2.0 for owners of the older units. Why do you want all this? So you can make accurate measurement of the differences between antennas, using a reference 1/2-wave dipole, or the standard RPSMA antenna you find on most Wifi Routers. The dB calibration of the Chanalyzer display is very accurate. Chuck W6PKP |
Help with Wifi antenna
On Jul 25, 8:13 am, "amdx" wrote:
Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide.http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike From my previous post on this topic: FYI, alt.internet.wireless discusses this topic often. I prefer the biquad antenna, which you can augment with a dish. I have a short-cut method to build this antenna. With a combination of these photographs and this link, you should be able to figure it out. http://martybugs.net/wireless/biquad/ http://www.lazygranch.com/images/wifi/wifi_bq_1.jpg http://www.lazygranch.com/images/wifi/wifi_bq_2.jpg Note you don't need to make the loop a square. Use a circle of the same circumference. There is a disadvantage to using the helix. It will receive both horizontal and vertical polarization. Most sites just send in one polarization. In busy areas, the same channel will be used in different sites with different polarity. Now if you use the helix to illuminate a dish, then the circular polarization is fine and perhaps desirable. That is, you could sniff out signals without the attenuation associated with having the wrong polarization. |
Help with Wifi antenna
"mike" wrote in message ... "Jerry Martes" wrote in message news:KGKpi.5345$Da.3887@trnddc07... "amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike Hi Mike You sure find some great information on the Web. I consider this article Jason Hecker publishes http://www.wlan.org.uk/jhecker.html to be ALL the instructions anyone would need for constructing a 20 dB directivity WiFi antenna. I am looking for some feedback from you on its performance. If you plan to investigate basic effects of changing size and shape of Helix antennas, EZNEC sure makes Helix antenna investigation easy. I am just curious, what kind of coax and connectors are you using, and, ?how much coax?. Jerry Hi Jerry, Please review the picture I posted on alt.binaires.schematics.electronic in it you will see I'm trying to avoid connectors and cable carrying 2.4Ghz R.F. Thanks for being the only poster to have anything near a response to my post. Mike Hi Mike My computer skills are really lacking. I dont know how to view your images. I do spend alot of time learning about antennas. One of my buddies tells me that he had poor results with the helix he built from the instructions you cited. This site seems to have been better for my buddy. http://www.pa0hoo.tk/. Is it practical for you to use a Bridge at the input terminals of your gain antenna so that the coax loss is minimized? That way, the antenna (+Bridge) is connected to the computer with CAT 5 cable. If it isnt too complicated, tell me how to view your images. Thanks Jerry |
Help with Wifi antenna
On Wed, 25 Jul 2007 12:09:30 -0700, Joel Kolstad wrote:
"Barry Watzman" wrote: That may be true but to use it that way legally you would need an amateur license, and this is not just a paperwork exercise, you have to pass FCC exams covering electronics and radio theory (plus laws and regulations) to get one. For most people, it's not an option. Very few people would have significnat difficulty passing the technician class license exam that's needed to operate on 2.4GHz. Indeed, there are many month-long (meet a couple times a week) classes and even weekend "cram" classes that have near 100% success rates in getting people their tickets. A passing score is 80%! But, I suppose that believing, as did an earlier poster: "Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!!" is acceptable for these No-Code, No-Klew Licensees? |
Help with Wifi antenna
Spaghettis should read Spaghettios "Chuck Olson" wrote in message ... "amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike The Wifi Helical antenna is an awful lot of work, and the performance of even long structures on PVC tubing is vastly disappointing. The easiest 15 dBi (my measurement) gain antenna is the Biquad. In fact, if you make the biquad with circular instead of square loops, the construction is even easier, and there's no problem measuring with all those bends - - just one wavelength of straight wire in a circular loop for each section - - http://www.wikarekare.org/Antenna/bicircle.html But try to keep a 50-ohm coaxial configuration all the way to the feed points as in http://homepages.ihug.co.nz/~redwood4/ It isn't necessary to keep the polyethylene insulation - - for a short length of air insulated coax, the tubing ID should be 2.25 times the center conductor OD for 50 ohms impedance. If you are like me, you will probably want to build the Helical anyway - - just to see, and perhaps to compare against the two easiest wifi antennas with decent performance - Biquad and Waveguide http://www.saunalahti.fi/elepal/antenna2.html The easiest waveguide can is the 83mm ID one you get with the 28oz size of Bush's Baked Beans or any of a number of other products like canned spaghetti sauce or family size Spaghettis. See if you can get a USB Wi-Spy Spectrum Analyzer module, too - - try to find one of the original (no external antenna - - cheaper) versions, and just put it in your own shielding enclosure and make your own modification to cut the path to the built-in antenna so that you can run a small coax to a connector on the box for your own external antenna connection. This kind of modification has been made by others - - http://www.metageek.net/default.aspx...5&view =topic scroll down to the post by pe2er on 9/9/06 showing how to connect a coax to the board. I used a type N connector on my enclosure because it's universal and strong, and filtered the three USB supply and signal wires with feed-thru capacitors so no RF can enter the enclosure through these other paths. Use Metageek.'s Chanalyzer software to run the Wi-Spy module - - preferably version 2.0 before the current 2.1.4 came out, since the need for compatibility with both the $199 Wi-Spy and the $399 Wi-Spy made operation with the $199 Wi-Spy somewhat unsatisfactory. Maybe you can ask Metageek to allow access to previous Chanalyzer 2.0 for owners of the older units. Why do you want all this? So you can make accurate measurement of the differences between antennas, using a reference 1/2-wave dipole, or the standard RPSMA antenna you find on most Wifi Routers. The dB calibration of the Chanalyzer display is very accurate. Chuck W6PKP |
Help with Wifi antenna
"Allodoxaphobia" wrote in message
... But, I suppose that believing, as did an earlier poster: "Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!!" is acceptable for these No-Code, No-Klew Licensees? That's what you get when at least the ARRL seems to be primarily interested in keeping the number of amateurs high even as society in general seems to be less and less willing to work a little for a bit of knowledge. Significant power is still hard enough to come by at 2.4GHz that most of them will probably run out of interest or money before doing *too* much damage. :-) That being said, it's not like you need that much power to go impressive distances anyway; see: http://www.wifiworldrecord.com/ . ---Joel |
Help with Wifi antenna
Dave Martindale wrote:
"mike" writes: Hi Jerry, Please review the picture I posted on alt.binaires.schematics.electronic in it you will see I'm trying to avoid connectors and cable carrying 2.4Ghz R.F. Thanks for being the only poster to have anything near a response to my post. Do note that many people's Usenet servers do not carry any binaries groups, so they will be unable to look at your picture. If you were to place the photo on a server where it can be accessed by HTTP or FTP, these people would be able to get it. Many ISPs provide some web space served by their own web server, and there are free photo hosting sites like flickr. Dave http://www.usenet-replayer.com/group...lectronic.html -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
Help with Wifi antenna
"Jerry Martes" wrote in message news:lePpi.8517$Ub7.1313@trnddc04... "mike" wrote in message ... "Jerry Martes" wrote in message news:KGKpi.5345$Da.3887@trnddc07... "amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike Hi Mike You sure find some great information on the Web. I consider this article Jason Hecker publishes http://www.wlan.org.uk/jhecker.html to be ALL the instructions anyone would need for constructing a 20 dB directivity WiFi antenna. I am looking for some feedback from you on its performance. If you plan to investigate basic effects of changing size and shape of Helix antennas, EZNEC sure makes Helix antenna investigation easy. I am just curious, what kind of coax and connectors are you using, and, ?how much coax?. Jerry Hi Jerry, Please review the picture I posted on alt.binaires.schematics.electronic in it you will see I'm trying to avoid connectors and cable carrying 2.4Ghz R.F. Thanks for being the only poster to have anything near a response to my post. Mike Hi Mike My computer skills are really lacking. I dont know how to view your images. I do spend alot of time learning about antennas. One of my buddies tells me that he had poor results with the helix he built from the instructions you cited. This site seems to have been better for my buddy. http://www.pa0hoo.tk/. Is it practical for you to use a Bridge at the input terminals of your gain antenna so that the coax loss is minimized? That way, the antenna (+Bridge) is connected to the computer with CAT 5 cable. If it isnt too complicated, tell me how to view your images. Thanks Jerry Hi Jerry, I posted the drawing on another newsgroup called alt.binaires.schematics.electronic Not all ISPs carry binairy files so maybe you can't see it, if your address is good I'll email the drawing. I looked at the site and it discouraged me. One site says 34mm diameter tube another 42mm, one says a 71mm impedance match strip then another says it's longer. I have no way to measure the antenna when finished so I'd like to at least start with the right dimensions. I will say at least the site you gave does have some equipment and his measurements and reasoning make sense. What is a bridge? I plan on putting a Usb wifi adapter at the antenna. I hope to remove the smt antenna on the USB wifi card and attach the helical antenna. Thanks, Mike |
Help with Wifi antenna
"Chuck Olson" wrote in message ... "amdx" wrote in message ... Please see subject line-- Help, Wifi Antenna-- on alt.binaires.schematics.electronic for a picture of my concept. Looking to combine Helical antenna and Wifi adapter card in one unit. My experience is limited to MW bcb. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. I'm using the following page as my guide. http://www.wlan.org.uk/jhecker.html This is to extend the range of my laptop computer. Mike The Wifi Helical antenna is an awful lot of work, and the performance of even long structures on PVC tubing is vastly disappointing. The easiest 15 dBi (my measurement) gain antenna is the Biquad. In fact, if you make the biquad with circular instead of square loops, the construction is even easier, and there's no problem measuring with all those bends - - just one wavelength of straight wire in a circular loop for each section - - http://www.wikarekare.org/Antenna/bicircle.html But try to keep a 50-ohm coaxial configuration all the way to the feed points as in http://homepages.ihug.co.nz/~redwood4/ It isn't necessary to keep the polyethylene insulation - - for a short length of air insulated coax, the tubing ID should be 2.25 times the center conductor OD for 50 ohms impedance. If you are like me, you will probably want to build the Helical anyway - - just to see, and perhaps to compare against the two easiest wifi antennas with decent performance - Biquad and Waveguide http://www.saunalahti.fi/elepal/antenna2.html The easiest waveguide can is the 83mm ID one you get with the 28oz size of Bush's Baked Beans or any of a number of other products like canned spaghetti sauce or family size Spaghettis. See if you can get a USB Wi-Spy Spectrum Analyzer module, too - - try to find one of the original (no external antenna - - cheaper) versions, and just put it in your own shielding enclosure and make your own modification to cut the path to the built-in antenna so that you can run a small coax to a connector on the box for your own external antenna connection. This kind of modification has been made by others - - http://www.metageek.net/default.aspx...5&view =topic scroll down to the post by pe2er on 9/9/06 showing how to connect a coax to the board. I used a type N connector on my enclosure because it's universal and strong, and filtered the three USB supply and signal wires with feed-thru capacitors so no RF can enter the enclosure through these other paths. Use Metageek.'s Chanalyzer software to run the Wi-Spy module - - preferably version 2.0 before the current 2.1.4 came out, since the need for compatibility with both the $199 Wi-Spy and the $399 Wi-Spy made operation with the $199 Wi-Spy somewhat unsatisfactory. Maybe you can ask Metageek to allow access to previous Chanalyzer 2.0 for owners of the older units. Why do you want all this? So you can make accurate measurement of the differences between antennas, using a reference 1/2-wave dipole, or the standard RPSMA antenna you find on most Wifi Routers. The dB calibration of the Chanalyzer display is very accurate. Chuck W6PKP Thanks Chuck, That BiQuad seems very simple and 14dbi seems like a lot for a simple small antenna. As for all the other fun stuff, not now, all I want now is internet access. But I need some gain. I'm still waiting for my USB wifi adapter card to arrive. I hope to have an antenna ready to connect to the USB wifi adapter card. Mike |
Help with Wifi antenna
amdx wrote:
If you wish to use a router/switch/adapter with a fixed antenna, this page may be helpful: http://www.freeantennas.com/projects/template/ Regards, JS Thanks Chuck, That BiQuad seems very simple and 14dbi seems like a lot for a simple small antenna. As for all the other fun stuff, not now, all I want now is internet access. But I need some gain. I'm still waiting for my USB wifi adapter card to arrive. I hope to have an antenna ready to connect to the USB wifi adapter card. Mike |
Help with Wifi antenna
Hi Jerry, I posted the drawing on another newsgroup called alt.binaires.schematics.electronic Not all ISPs carry binairy files so maybe you can't see it, if your address is good I'll email the drawing. I looked at the site and it discouraged me. One site says 34mm diameter tube another 42mm, one says a 71mm impedance match strip then another says it's longer. I have no way to measure the antenna when finished so I'd like to at least start with the right dimensions. I will say at least the site you gave does have some equipment and his measurements and reasoning make sense. What is a bridge? I plan on putting a Usb wifi adapter at the antenna. I hope to remove the smt antenna on the USB wifi card and attach the helical antenna. Thanks, Mike Hi Mike I am too much 'a beginner' to be a good advisor for how to hook up devices for WiFi reception. So, I wont try to define what a Bridge is. I will do about anything (affordable) that allows the elimination of the coax in a 2.4 GHz system. I do have some experience with making WiFi systems to extend the distance at which Internet connections can be achieved. On one system I made for a guy in Ranchita Calif, who has an agricultural business about 1/4 mile from his house. I put an access point on a 4 foot diameter dish so he uses only CAT 5 cable from his home Router to illuminate the dish. I then put a Bridge on a smaller dish with CAT 5 cable to connect that dish to his lap top in the field. It worked. My objective was to be able to use highly directive antennas yet minimize coax line losses. I think the use of a USB wireless adapter (TRENDnet TEW-445UB) Would be easier than the way I made my system. Show Me cables sells reversing polarity adapters that make it possible to use normal SMA connectors to the TRENDnet USB TEW-445UB Your project interests me. Tell me what you finally decide to do. I have rejected the Helix. They are more difficult for me to understand than a Yagi. The Helix is circularly polarized, so you loose 3 dB "off the top" of any gain (directivity) plots. The Yagi is fairly easy to model with EZNEC, so you can be fairly well assured that whatever you build will work like the model. Jerry |
Help with Wifi antenna
"Jerry Martes" wrote in message news:aqSpi.3837$7w.79@trnddc05... Hi Jerry, I posted the drawing on another newsgroup called alt.binaires.schematics.electronic Not all ISPs carry binairy files so maybe you can't see it, if your address is good I'll email the drawing. I looked at the site and it discouraged me. One site says 34mm diameter tube another 42mm, one says a 71mm impedance match strip then another says it's longer. I have no way to measure the antenna when finished so I'd like to at least start with the right dimensions. I will say at least the site you gave does have some equipment and his measurements and reasoning make sense. What is a bridge? I plan on putting a Usb wifi adapter at the antenna. I hope to remove the smt antenna on the USB wifi card and attach the helical antenna. Thanks, Mike Hi Mike I am too much 'a beginner' to be a good advisor for how to hook up devices for WiFi reception. So, I wont try to define what a Bridge is. I will do about anything (affordable) that allows the elimination of the coax in a 2.4 GHz system. I do have some experience with making WiFi systems to extend the distance at which Internet connections can be achieved. On one system I made for a guy in Ranchita Calif, who has an agricultural business about 1/4 mile from his house. I put an access point on a 4 foot diameter dish so he uses only CAT 5 cable from his home Router to illuminate the dish. I then put a Bridge on a smaller dish with CAT 5 cable to connect that dish to his lap top in the field. It worked. My objective was to be able to use highly directive antennas yet minimize coax line losses. I think the use of a USB wireless adapter (TRENDnet TEW-445UB) Would be easier than the way I made my system. Show Me cables sells reversing polarity adapters that make it possible to use normal SMA connectors to the TRENDnet USB TEW-445UB Your project interests me. Tell me what you finally decide to do. I have rejected the Helix. They are more difficult for me to understand than a Yagi. The Helix is circularly polarized, so you loose 3 dB "off the top" of any gain (directivity) plots. The Yagi is fairly easy to model with EZNEC, so you can be fairly well assured that whatever you build will work like the model. Jerry Jerry, I was thinking you would come back and say a bridge is the same as a usb wifi adapter, but I guess not. Have you looked at my drawing I sent you? Mike |
Help with Wifi antenna
In article ,
amdx wrote: Jerry, I was thinking you would come back and say a bridge is the same as a usb wifi adapter, but I guess not. Mike, If I may chime in here... In somewhat-simplified Ethernet-networking terms, a "bridge" is a device which joins two Ethernet segments together, by forwarding Ethernet packets from one network to the other based on the Ethernet MAC address of the system to which the packet is being sent. It makes the decision to forward (or not) without changing (or even acting upon) their contents at any higher protocol level (e.g. IP address). An Ethernet switch is a form of bridge. In most respects, a bridge is "invisible" to the systems whose packets it is forwarding - they don't even know it's there. This is distinguished from a router, which makes the forwarding decision based on a higher-level protocol (e.g. IP address), and which is "known" directly to the systems that are using it. An 802.11 access point tends to behave like a bridge, from the point of view of those devices which are connected to its wired-Ethernet ports. The devices whose packets are being bridged (via radio) out through the access point don't realize that this is occurring. In most 802.11 applications, the wireless client systems *do* know that they're talking to an access point - they do all of the 802.11 protocol stuff (e.g. access-point scanning, requesting association, the client side of key negotiation, etc.) themselves, in the device adapter or firmware or driver. The USB or PCI 802.11 interfaces in these devices are *not* bridges. However, it's possible to build a device which looks outwardly like an 802.11 access point, in that it has a radio and antenna(s) and an Ethernet port, but which implements the _client_ side of 802.11 rather than the access-point side. You can then connect this to a PC (via wired Ethernet), and *it* will establish an 802.11 connection with an existing access point, and then start bridging packets from the wired Ethernet to the access point. The PC plays no direct part in the wireless connection setup - it simply transmits packets to what it "thinks" is a hub or switch, and the "wireless bridge" sends them to the access point. You'll sometimes see these devices referred to as a form of "gaming adapter", because they often have higher performance than typical USB or PCI 802.11 adapters and don't burden the host CPU as much... and are thus popular with players of high-performance PC videogames. Many of the newer all-in-one "802.11 access point, router, firewall, and wired-Ethernet switch" products can be configured in this way via software... they'll take the client role in an 802.11 network just as happily as the role of an access point. Most of them cannot do both things at once - they can serve as an outbound bridge, or as an access point for a local WLAN, but not both. So, I think you have at least three basic alternatives for how you can set up the remote/client end of a longer-distance wireless link: - Run a big, heavy low-loss coaxial cable from your PC's 802.11 adapter antenna jack, up to your antenna (dish or biquad or helical or waveguide-can). For really low loss over long distances, plan on using something like 2" heliax (which is to say, you really don't want to do this!) - Run a USB cable (extended as necessary with 15' "active" USB repeater cables) up to the antenna, and connect a USB/802.11 adapter there (e.g. stick the adapter at the focal point of a dish, or at the feedpoint in a waveguide can). Google for "Wok-fi". - Run a CAT-5 Ethernet cable and DC power up to the dish, install an 802.11 bridge right at the antenna, and connect the Ethernet cable to your PC's wired-Ethernet port. It's worth noting that most methods of attaching an external antenna to a commercial 802.11 adapter are likely to void the adapter's Part 15 certification, and make the adapter techically illegal to use for transmission. 802.11 radios and their associated antennas are required to be tested and certificated as a complete system. I've rarely heard of anyone being hassled by the FCC for doing this, though. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Help with Wifi antenna
On Wed, 25 Jul 2007 10:13:26 -0500, "amdx" wrote:
Help, Wifi Antenna Looking to combine Helical antenna and Wifi adapter card in one unit. I know there are many pitfalls at 2.4Ghz, so I'm looking for feedback on how to do this properly. This is to extend the range of my laptop computer. Why not to use an older 802.11g Usb Wlan stick (good one w/ onboard chip smd ceramic antenna, much better than w/ Pcb printed one) & some "metal" DIY "range enhancers" ? :-) See pics & data & measures in cm to get some clues & ideas (text is in my native-slovene, so you won´t understand it; sorry, still had no time to make an english version of that articles for those UsbKey active antennas; inside URLs can be also seen at wish...) DIY wifi USBkeY range Enhancers-boosters ´4 Dummies´ :-) http://www.wlan-sat.com/modules.php?...=26476#264 76 Ultimate wifi antenna TinCan Enhancers - part-2 ... :-) http://www.wlan-sat.com/modules.php?...ewtopic&t=4782 problems with Usb cable lenght limitation? No more even w/o powered hubs ... :-) (DIY, custom up to 21m, all data in english there on schematics!)) http://www.wlan-sat.com/modules.php?...ewtopic&t=4216 Have fun! :-) There is also to check other stuff at wish: Default Wlan Pci Card antenna_on_cable Enhancer 6dBi http://www.wlan-sat.com/modules.php?...ewtopic&t=3847 Cornet enhancers for some different type antennas up to 12dBi http://www.wlan-sat.com/modules.php?...ewtopic&t=4241 & also parabolic pot or wok cover (+ bucket shape add-on) "passive" antenna experiment with at least 20dBi gain: ST™-maxX antena (= project-X) 21dbi http://www.wlan-sat.com/modules.php?...ewtopic&t=3993 well, I think that now you´ve got enough material (pics & drawings/sketches) to check & maybe try some stuff by yourself :-)) -- Regards , SPAJKY ® mail addr. @ my site @ http://www.spajky.vze.com 5y - "Tualatin OC-ed / BX-Slot1 / inaudible setup!" |
Help with Wifi antenna
" Well.. not all the 802.11b/g channels are in the amateur band, and even there, there is a power limit (transmitter output power, though, not EIRP), so you could conceivably fire up your 1500 Watt transmitter into a 20dBi antenna and blast away. That is what the moonbounce operators do, but with more antenna gain!! There is the other rule about minimum power needed for communication, though. Again moonbounce is not uncommon in the 13cms band. Jeff |
Help with Wifi antenna
"Allodoxaphobia" wrote in message ... On Wed, 25 Jul 2007 18:12:26 +0100, Jeff wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Oh , really ?! cite! Channels 1 to 6 lie with the 13cms amateur band, which does vary a little from country to country nut in the UK is 2310-2450MHz, and there is no ERP restriction in this band just a max power to the antenna, which can have as much gain as you can muster. Jeff |
Help with Wifi antenna
On Thu, 26 Jul 2007 09:15:44 +0100, Jeff wrote:
"Allodoxaphobia" wrote in message ... On Wed, 25 Jul 2007 18:12:26 +0100, Jeff wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Oh , really ?! cite! Channels 1 to 6 lie with the 13cms amateur band, which does vary a little from country to country nut in the UK is 2310-2450MHz, and there is no ERP restriction in this band just a max power to the antenna, which can have as much gain as you can muster. For amateur radio, it's a limit on DC power to the final amplifier, which you can make as efficient as you want; it's average power, so you can run 2 KW PEP (peak envelope power) SSB, and gawd knows what kinds of pulses you're allowed to transmit on the UHF, SHF, and EHF bands, as long as the average isn't over 1 KW input to the final. I'm sure it's all covered in the FCC regs, which should be easy to look up for anyone who's really that interested. ;-) Cheers! Rich |
Help with Wifi antenna
On Thu, 26 Jul 2007 09:13:02 +0100, Jeff wrote:
" Well.. not all the 802.11b/g channels are in the amateur band, and even there, there is a power limit (transmitter output power, though, not EIRP), so you could conceivably fire up your 1500 Watt transmitter into a 20dBi antenna and blast away. That is what the moonbounce operators do, but with more antenna gain!! There is the other rule about minimum power needed for communication, though. Again moonbounce is not uncommon in the 13cms band. Yikes! I was just doing a little calculating, and you could put a 20 dB Yagi in your shirt pocket! =:-O ;-) Rich (OK, my shirts have big pockets... ;-) ) |
Help with Wifi antenna
In article ,
Rich Grise wrote: Channels 1 to 6 lie with the 13cms amateur band, which does vary a little from country to country nut in the UK is 2310-2450MHz, and there is no ERP restriction in this band just a max power to the antenna, which can have as much gain as you can muster. For amateur radio, it's a limit on DC power to the final amplifier, which you can make as efficient as you want; it's average power, so you can run 2 KW PEP (peak envelope power) SSB, and gawd knows what kinds of pulses you're allowed to transmit on the UHF, SHF, and EHF bands, as long as the average isn't over 1 KW input to the final. I'm sure it's all covered in the FCC regs, which should be easy to look up for anyone who's really that interested. ;-) I thought that the FCC had abandoned the "DC input power to the final" standard quite some time ago (a decade or more, I think). Most of the transmitter power standards for hams are in in 97.313, which describes all of the limits in terms of PEP. Duty cycle, modulation, and final efficiency are apparently no longer relevant in most cases. For most bands, and most operator classes, "legal limit" is 1500 watts PEP. There are plenty of exceptions based on band, operator class, and modulation (spread spectrum in particular) but these limits are almost always defined in terms of PEP, which is referenced at the transmitter-feedline connection. There are some time-averaged and/or ERP limits described elsewhere in Part 97, but these all seem to have to do with deciding when a particular station must go through an evaluation for just how much RF it's exposing humans in the area to. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Help with Wifi antenna
Barry Watzman wrote in news:46a7981e$0$30632
: That may be true but to use it that way legally you would need an amateur license, and this is not just a paperwork exercise, you have to pass FCC exams covering electronics and radio theory (plus laws and regulations) to get one. For most people, it's not an option. And when you do get that license, you are, by lay, limited on what you can communicate. IMO. boosting your home wi-fi unser the auspices of an Amateur Radio License is a no-no. |
Help with Wifi antenna
"amdx" wrote in
: Jerry, I was thinking you would come back and say a bridge is the same as a usb wifi adapter, but I guess not. Have you looked at my drawing I sent you? In a nutshell, a bringe in the wi-fi sense as you should get, is a box that has an ethernet adapter and a wi-fi adapter. It is kinda like a WAP, but backwards. It allows you to use an ethernet device like your computer, on a wireless network using its ethernet connection. You would want to use that as you can locate the bridge at the antenna, and connect your computer to the bridge with as long as an ethernet cable (up to 330 ft though) as you need. USB would be quite limited. |
Help with Wifi antenna
"Gary Tait" wrote in message
... And when you do get that license, you are, by lay, limited on what you can communicate. Well, the main one is (paraphrased) that you can't be using the amateur bands for making money on a regular basis... although on-the-air swap meets, ordering pizza at Pizza Hut via the Internet, books through Amazon, etc. is certainly all kosher. Were there other exceptions you were thinking of? IMO. boosting your home wi-fi unser the auspices of an Amateur Radio License is a no-no. As long as you don't use encryption and aren't running your business through it, in my opinion it's a perfectly reasaonble use. Heck, even QST has articles on doing so. |
Help with Wifi antenna
Rich Grise wrote:
On Thu, 26 Jul 2007 09:15:44 +0100, Jeff wrote: "Allodoxaphobia" wrote in message ... On Wed, 25 Jul 2007 18:12:26 +0100, Jeff wrote: Note that in almost all places there are legal limitations on EIRP (Effective Incident Radiated Power). In plain English, the more you narrow a signal, the stronger it becomes. Since you did not say where you are, I'll mention the two places I know for sure. In the U.S. WiFi EIRP is limited to 1 watt for mobile/portable use (e.g. laptops) and 4 watts for fixed links. Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!! Oh , really ?! cite! Channels 1 to 6 lie with the 13cms amateur band, which does vary a little from country to country nut in the UK is 2310-2450MHz, and there is no ERP restriction in this band just a max power to the antenna, which can have as much gain as you can muster. For amateur radio, it's a limit on DC power to the final amplifier, which you can make as efficient as you want; it's average power, so you can run 2 KW PEP (peak envelope power) SSB, and gawd knows what kinds of pulses you're allowed to transmit on the UHF, SHF, and EHF bands, as long as the average isn't over 1 KW input to the final. So in the UK, they still regulate on the basis of DC power? Interesting. I've always liked that philosophy because it promotes design of efficient amplifiers. I'm sure it's all covered in the FCC regs, which should be easy to look up for anyone who's really that interested. ;-) 1.5 kW PEP, except in certain bands with lower limits (5 MHz, 430-450 MHz (depending on what your location is), etc.) no averaging for pulses.. 97.3(b)(6) PEP (peak envelope power). The average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions. You can transmit pulses on 900 MHz and 2300 MHz and all higher bands, but not 1.2 GHz (although you might be able to do pulses as part of a data or spread spectrum modulation). Clearly, if you want to operate a radar with your amateur license, you're better off with one using pulse compression and long pulses. Cheers! Rich |
Help with Wifi antenna
Joel Kolstad wrote:
"Gary Tait" wrote in message ... And when you do get that license, you are, by lay, limited on what you can communicate. Well, the main one is (paraphrased) that you can't be using the amateur bands for making money on a regular basis... although on-the-air swap meets, ordering pizza at Pizza Hut via the Internet, books through Amazon, etc. is certainly all kosher. Were there other exceptions you were thinking of? IMO. boosting your home wi-fi unser the auspices of an Amateur Radio License is a no-no. As long as you don't use encryption and aren't running your business through it, in my opinion it's a perfectly reasaonble use. Heck, even QST has articles on doing so. Indeed? Which issue? I recall some articles about HSMM and building a slotted array with gain, but not wholesale use for extension of your internet connection. I think that if you start to stray too far from incidental commercial use, you could get into trouble, especially if lots folks start doing it. The classic pizza over the autopatch is the example, and I suppose the occasional ordering from Amazon fits in the same category. But, if were to, for instance, check your work email, or watch pay-per-view content, you might be pushing it. In particular, if you but a PA on your access point and a directional antenna, so that your neighbor can use it too, you're likely to be stepping over the line. It's all a judgement call, but the intent is that amateur radio not be used where there is a commercial service that can provide the same functions. This is so the commercial entities can't claim that someone using amateur frequencies is getting an unfair competitive advantage (among other reasons) |
Help with Wifi antenna
So in the UK, they still regulate on the basis of DC power? Interesting.
I've always liked that philosophy because it promotes design of efficient amplifiers. Not for many years. The normal UK limit, for a full licence, is 400W pep into the antenna on most bands. Jeff |
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