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

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 gsm@mendelson.com N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

"amdx" <amdx@knology.net> wrote in message
news:e2a88$46a76893$18d6b40c$7378@KNOLOGY.NET...
> 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

> 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

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!

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.

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.

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!

"gwatts" <gwatts@frontiernet.net> wrote in message
news:6wMpi.12851$B25.3670@news01.roc.ny...
> 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

"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
news:46a7981e$0$30632$4c368faf@roadrunner.com...
> 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%!

"Jerry Martes" <j.jmartes@verizon.net> wrote in message
news:KGKpi.5345$Da.3887@trnddc07...
>
> "amdx" <amdx@knology.net> wrote in message
> news:e2a88$46a76893$18d6b40c$7378@KNOLOGY.NET...
>> 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

"Jeff" <jeff@local.host> wrote in
news:46a784ab$0$1347$834e42db@reader.greatnowhere. 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.

On 7/25/07 10:12 AM, in article
46a784ab$0$1347$834e42db@reader.greatnowhere.com, "Jeff" <jeff@local.host>
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.

"amdx" <amdx@knology.net> wrote in message
news:e2a88$46a76893$18d6b40c$7378@KNOLOGY.NET...
> 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...395&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

"mike" <amdx@knology.net> 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