[TriLUG] Wireless access

Tue Sep 23 12:12:20 EDT 2003

It was in your reply to the list, but here it is again:

http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_shee
t09186a008008883b.html

--Reggie

> -----Original Message-----
> From: trilug-bounces at trilug.org 
> [mailto:trilug-bounces at trilug.org] On Behalf Of Ralph Blach
> Sent: Tuesday, September 23, 2003 12:08 PM
> To: Triangle Linux Users Group discussion list; Reginald Reed
> Subject: Re: [TriLUG] Wireless access
> 
> 
> Reginald,
> 
> I agree.  Good going Cisco.
> 
> Where is the page??
> 
> I want to see if this is applicable to my ham club
> 73's de Chip
> KF4WBK
> 
> 
> 
> 
> Reginald Reed wrote:
> > Ralph,
> > 
> > In the link I posted, it shows what Cisco sells for 
> antennas that do 
> > not require an FCC license.  I'm not an RF expert, but according to 
> > the web page, all of the antennas listed, including the 
> dish with 21 
> > dB gain are within the specifications for legal usage.
> > 
> > --Reggie
> > 
> > 
> >>-----Original Message-----
> >>From: trilug-bounces at trilug.org
> >>[mailto:trilug-bounces at trilug.org] On Behalf Of Ralph Blach
> >>Sent: Tuesday, September 23, 2003 11:22 AM
> >>To: Triangle Linux Users Group discussion list
> >>Subject: Re: [TriLUG] Wireless access
> >>
> >>
> >>
> >>Reggie,
> >>
> >>A parabolic dish would work of course, but the problem is the
> >>that is has the wireless unit has not been qualified with a 
> >>Parabolic by the FCC to work with these units. see slashdot
> >>
> >>And has a ham who follows the FCC enforcment, I would NOT
> >>want the FCC on my door step with an injuction.  It can get 
> >>real messy reall fast.  With the new SAR requirements by the 
> >>FCC, I only operate Low power so I dont have to prove I am 
> >>below the SAR requirements.
> >>
> >>This is not about will it work and can it be made to work (It
> >>clealy can, and easily at that) but navigation of the FCC to 
> >>allow you to do it.
> >>
> >>73's de Chip
> >>kf4wbk
> >>
> >>
> >>
> >>Reginald Reed wrote:
> >>
> >>>If you are doing point to point over a long distance with
> >>
> >>clear line
> >>
> >>>of sight, I'd use something more directional than a Yagi.
> >>
> >>I'd use a
> >>
> >>>parabolic dish.
> >>>
> >>>--Reggie
> >>>
> >>>
> >>>
> >>>>-----Original Message-----
> >>>>From: trilug-bounces at trilug.org 
> [mailto:trilug-bounces at trilug.org] 
> >>>>On Behalf Of Ron Joffe
> >>>>Sent: Tuesday, September 23, 2003 10:24 AM
> >>>>To: Triangle Linux Users Group discussion list
> >>>>Subject: Re: [TriLUG] Wireless access
> >>>>
> >>>>
> >>>>On Tuesday 23 September 2003 10:10 am, Ron Joffe wrote:
> >>>>
> >>>>
> >>>>>On Tuesday 23 September 2003 09:19 am, Ralph Blach wrote:
> >>>>>
> >>>>>
> >>>>>>your yaggi might be able to get the Job done, but it would most 
> >>>>>>assuredly violate the FCC rules.  Remeber, that these radio's 
> >>>>>>operate in the 2.4 ghz ham band and are Secondary users.
> >>>>
> >>>>That means
> >>>>
> >>>>
> >>>>>>that you will have to put up with Ham activities causing 
> >>>>>>interference.
> >>>>>
> >>>>>Would hooking up a Yaggi antenna directly to a commercial 802.11 
> >>>>>broadband bridge without amplification violate any FCC Rules?
> >>>>>
> >>>>>Ron
> >>>>
> >>>>Well I answered my own question. In the cisco link that
> >>
> >>Reginald sent:
> >>
> >>>
> >>http://www.cisco.com/en/US/products/hw/wireless/ps469/produc
> ts_data_sh
> >>
> >>>ee
> >>>t09186a008008883b.html
> >>>
> >>>It states:
> >>>
> >>>" In Point-to-Multipoint systems, the FCC has limited the
> >>
> >>maximum EIRP
> >>
> >>>(effective isotropic radiated power) to 36dBm. EIRP = TX
> >>
> >>power + antenna
> >>
> >>>gain. For every dB that the transmitter power is reduced,
> >>
> >>the antenna
> >>
> >>>may be increased by 1dB. (29dBm TX, +7dB antenna = 36dBm
> >>
> >>EIRP, 28dBm
> >>
> >>>TX, +8dB antenna = 36dBm EIRP).
> >>>
> >>> The Cisco Aironet Bridge transmitter power is 20dBm, which
> >>
> >>is 10dBm
> >>
> >>>lower than maximum. This then allows the use of antennas up to 10dB
> >>>over the initial 6dBi limit, or 16dBi.
> >>>
> >>> In Point-to-Point systems for 2.4GHz systems, using directional
> >>>antennas, the rules have changed. Because a high gain 
> antenna has a 
> >>>narrow beamwidth, and
> >>>therefore the likelihood is high that it will cause interference to
> >>>other 
> >>>area users. Under the rule change, for every dB the transmitter is
> >>>reduced 
> >>>below 30dBm, the antenna may be increased from the initial 
> >>
> >>6dBi, by 3dB.
> >>
> >>>(29dB Transmitter means 9dBi antenna, 28dB transmitter means 12dBi
> >>>antenna). Because we are operating at 20dBm, which is 10dB 
> >>
> >>below the
> >>
> >>>30dBm level, we
> >>>can increase the out antenna by 30dB. However Cisco has
> >>
> >>never tested,
> >>
> >>>and
> >>>therefore is not certified with any antenna larger than 21dBi."
> >>>
> >>>So I read this to mean that using a cisco aironet bridge, I
> >>
> >>should be
> >>
> >>>able to legally use up to a 36dbi Yaggi antenna.
> >>>
> >>>Ron
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>-- 
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> >>
> > 
> > 
> 
> 
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