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