[ath9k-devel] Ubiquity SR71-E: direct probe timed out

From: Alex Hacker <hacker@epn.ru>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] Ubiquity SR71-E: direct probe timed out
Date: Mon, 1 Aug 2011 16:15:14 +0600	[thread overview]
Message-ID: <20110801101514.GA16146@infinet.ru> (raw)
In-Reply-To: <CAJ-VmomTsyASfuZWe6EOVzsWG==tgDn=0WEwvdo=XMbKAuzMng@mail.gmail.com>

Hi, Adrian!
Yeah, the Ubiquity is young company trying to get his place on the market.
So that they like to overdrive Sirenza RF PAs to impermissible levels. This
leads to raising unwanted emission in adjacent channels, but I don't
believe that they have a fake FCC certificate. :) Another issue with Ubiquity
cards is the absence of output RF filters, so it can emit some 2nd (>4.8GHz)
and 3rd (>7.2 GHz) harmonics when work at high power.
BTW the SR71 specification claims 26dBm at MCS0 and only 19dBm at MCS7.
Anyway if you do not use adjacent channels it is should not be a big problem
(except for the neighbouring networks of course).

Best regards,
Alex.

On Mon, Aug 01, 2011 at 05:07:36PM +0800, Adrian Chadd wrote:
> I've also noticed that there's sometimes quite noticable differences
> in how "clean" the output is from various NICs.
> 
> Eg, when pushing the SR-2 or SR-71A at max power, versus the Unex DNMA
> series high power NICs. The Unex ones are much, much cleaner.
> 
> 
> Adrian
> 
> 
> On 1 August 2011 16:31, Alex Hacker <hacker@epn.ru> wrote:
> > Important exeption is the channel sidebands and baseband filters fall-off. You
> > sholdn't use adjacnt channels for different networks. At least 40MHz gap
> > should be left between H20 channels, and as much as 80MHz between HT40+ and
> > HT40- channels.
> >
> > On Mon, Aug 01, 2011 at 11:19:03AM +0600, Alex Hacker wrote:
> >> Really boys, it's unbelievable story! We works with Atheros based cards for
> >> years, our RF engenners have spectrum analyzers connected to these cards
> >> continuously. I'd just ask him - nobody never see any out of band interference
> >> from these cards except the pci-e carrier at 2.5 and 5.0 GHz. So I'm shure that
> >> the issue lies somewhere else, not in RF plane.
> >> About antennas. Of coarse any object in the anntenna near field causes a
> >> distortion of gain/directivity and SWR so that the system performance can
> >> degrade. Anyway passive antenna system can not be source of out of band
> >> interference.
> >>
> >> With best regrads,
> >> Alex.
> >>
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