RE: Radio Ethernet Modem Experiences

[jseymour () linxnet com (Jim Seymour)]

"Kelly, Chris W." <ckelly () hsutx edu> wrote:
> What he said. Although, don't completely expect a pair of nice expensive
> parabolic high gain dishs to completely give you secure and reliable
> communications.  We had a link of about 5000' for a year and a half.  It
> worked well for about 12 months, then slowly went to hell.  We never did
> specifically ID a cause and replaced the link with a deicated T1 circuit
> and routers.  Web/email was always good, Microsoft network applications
> so-so.  
[snip]

> From reading the rest of Kelly's comments, I'm guessing they had an
802.11<something> or otherwise so-called "unlicensed spectrum"
microwave solution.  Now I'm glad I didn't try that ;).

We had two buildings, about 1/4-mile apart, to connect.  I didn't want
to pay the recurring monthly T1 charges and getting rights-of-way
across all those intervening properties, plus crossing the street, was
unlikely.

We had a *licensed* point-to-point microwave system installed.  This
was something that would normally do up to 30 miles, LOS and with the
proper antennas.  They had to install negative-gain antennas in our
application, because the transmitters couldn't be dialed-back far
enough to prevent overloading the receivers, that close.  It was a
10mb/s full-duplex system, IIRC.

I believe my employer probably about broke even over the approximate
three years the system was in place, as compared to a T1, and got
10mb/s, as opposed to 1.544mb/s.

Security was somewhat of a concern.  (The manufacturer insisted that
the signal was so narrow, physically, that it couldn't be intercepted
unless somebody stuck something up right between the antennas.  I had
an Advanced Class Amateur license, an FCC commercial radiotelephone
operator's license, passed the U.S.  Army's Advanced Strategic
Microwave Systems Repair course with flying colours and taught
Satellite Communications for two years.  I knew better ;).)  I mainly
relied on it being proprietary technology, in a licensed part of the
spectrum, and the power being so dialed-back.  Basically security by
"it's highly unlikely."

System never gave us a *moment* of trouble.  Ran day and night.  Ran
through driving snow and torrential rain.  Never missed a beat.  (Well,
other than when a fuse in one of the radios unaccountably gave up the
ghost.)

The system was finally taken off-line when one of the two buildings was
sold during down-sizing.

The name of the company was Microwave Bypass Systems.  When I search on
that, all I come up with that's legitimate is Airlinx Communications,
which looks like a reseller.  Can't find a working on-line presence for
MBS.  The phone number I have for them isn't answered.  All I get at
Airlinx is a "we can't come to the phone right now" (which isn't
encouraging at 10 a.m. on a workday morning).  I suspect Microwave
Bypass Systems is no more :(.

Jim
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