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%!