shaeffer at best.com
Tue Jun 13 02:05:12 PDT 2000
On Tue, Jun 13, 2000 at 12:09:37AM -0700, Jeffrey B. Siegal wrote:
> Karen Shaeffer wrote:
> > These are products that are limited to transmitting distances of a about
> > 50 feet or less. The antennas have no directivity and they operate in the
> > unlicensed ISM bands, which restrict radiation power to <= 1mw.
> Not necessarily.
> This site talks about using directional antennas with Apple's AirPort
> cards and hubs (802.11b devices made by Lucent I think) and achiving
> ranges of up to 57km! The site claims that antennas below 24db gain are
> permissible under FCC regulations:
> Information about Lucent's outdoor 802.11b products is available here:
> This site similarly suggests that only the 24db antenna requires FCC
> Lucent reports similar multi-kilometer distances here:
---end quoted text---
Great. I didn't say it couldn't be done. I just said the product lines
mentioned were not capable of directed transmission. In principle, 802.11b
can be encapsulated in any wireless modulation scheme and transmitted like
any other data for whatever distance the transmitter is designed for.
These products you mention are interesting. They are microwave, directed
As for licensing, the one site says:
In New Zealand, the document relating to radio frequency compliance is found at
www.moc.govt.nz/rsm/rfs29.pdf. Output power must be less than 4000 mW. My
understanding is that the New Zealand regulations are the same as the FCC (US)
for the Airport cards, but you should check for compliance in your country.
Actually Jeff, this is not correct.
In the US, the wireless LAN systems run on the unlicensed ISM bands at
902-928MHz, 2400-2483.5MHz, and 5725-5850MHz. These ISM bands are allocated
by the FCC as unlicensed for systems that utilize spread spectrum modulation
techniques and radiate <= 1 Watt of radiated power. (I retract my earlier
statement claiming the standard <= 1mw, which is generally the transmitted
power of portable, battery operated devices--but well below the FCC limits.)
Thanks for your comments. That's interesting technology.
Neuralscape; Santa Cruz, Ca. 95060
shaeffer at neuralscape.com http://www.neuralscape.com
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