[Ham-Computers] ADVICE - wireless

[Jay Eimer]

Some don't seem to have problems with RF and wireless part 15 devices,
others do.

Here's one for ya all.  My old office was about 150' long, both sides of a
hall, and numerous internal partitions (old building, with substantial lath
and plaster, not "cubeland").

The servers were at one end.  The boss's office (the owner) was at the
other.  He wanted to "wireless" his notebook, so he could move to the
conference room w/o dragging a wire along.  (He could unplug and replug, but
that was too inconvenient for him, if that tells you anything <g>).

So, one access point and one PCMCIA card later, he has a conn on the
technicians desk.  But no go in his office.  Turns out that you get (in that
building) exactly 3 walls or 70', whichever comes first, before the signal
drops too low to be reliable.

So, off they go again to buy a Radio Shack "booster" antenna (oversize
antenna, presumably with gain, and a pre-amp).  I tell them that this is
probably only quasi-legal (they're pushing part 15 emissions limits, and
that it's not gonna work.

Sure enough, every time a UPS truck goes by (major intersection right below
the boss's windows, but the servers are in the furthest part of the building
from the street), the network connection drops.  They didn't figure that one
out at first.  But I brought in an HT (5W) and keyed up on 2m and 440.
Either one drops the link.  I don't know, presumably just front end
overload, since there shouldn't be harmonics of either signal where the
wireless is working.  W/O the antenna booster its the same.  But w/booster
(and w/o my HT) the link would still drop regularly but intermittently
(usually during a large file copy or save!).  We started watching and it
turned out it was UPS or FedEx trucks.  Probably their APRS, package
tracking, or dispatch radios (not sure what they have, but....)  Also some
(but not all) semis or delivery trucks, etc.  I suspect that its just any
reasonably high power business band radio just flat out overloads and
desenses the lan.

Jay
AD5PE

-----Original Message-----
From: ham-computers-bounces at mailman.qth.net
[mailto:ham-computers-bounces at mailman.qth.net]On Behalf Of Rolly (W7DGX)
& Sandra Goodspeed
Sent: Sunday, August 15, 2004 07:05
To: Computers (or other) used for amateur radio, communications, or
experimenting
Subject: Re: [Ham-Computers] ADVICE - wireless


I am curious about wireless LAN.

I have experimented with wireless keyboards and mouse. Both worked fine
until I transmitted. Somewhere in the 30 to 50 watt range these wireless
devices would quit entirely or become intermittent. At my normal 90 watt
level the wireless keyboard and mouse were inoperative. I also have problems
with the indoor/outdoor thermometers. These devices operate around 432 MHz.

Because of this, I question all wireless devices around amateur radio,
especially inexpensive ones. I have found the good (not cheap) 900 MHz and
above wireless phones to be relatively immune. Sometimes running near legal
limit power, there will be a scratchiness on voice peaks.

The exception to this is 75 meter operation. There I have a phone line
running between the house and the garage that is about 35 feet long, and
approximately 12 feet in the air. My 75 meter dipole runs almost parallel
with that phone line and is only 22 feet high. Thus high power 75 meter
operation kills the phone regardless if a cordless phone is used or not.

As soon as I am well enough, I expect to bury that line. Hopefully that will
resolve that problem. If not,  I may remove the line entirely to the garage
and put a 900 MHz or above wireless extension in the garage.

  Rolly W7DGX

----- Original Message -----
From: "jeff" <jeffv at op.net>
To: "Computers (or other) used for amateur radio, communications, or
experimenting" <ham-computers at mailman.qth.net>
Sent: Saturday, August 14, 2004 7:40 PM
Subject: [Ham-Computers] ADVICE - wireless


> On Sat, 2004-08-14 at 21:10, Don wrote:
> > thanks
> > WIRELESS next year when a add laptop
>
>
> Don -
> It gets better.  No matter what you're told, wireless is insecure.  Be
> aware that anything you transmit can be received, kind of like people
> with scanners picking up cordless and cel phones.
>
> If any of you decide to go wireless, please read up on security and
> enable every feature you can to provide additional security.
>
>
> If you're a security nut, don't go wireless.
>
>
> _______________________________________________
> Ham-Computers mailing list
> Ham-Computers at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/ham-computers
>

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