One comment regarding the bench testing of any radio.
Too much signal is just as bad as too little signal because an
overloaded receiver will create errors just like a receiver that
doesn't get enough signal.
When bench testing, I advise either placing the units several rooms
apart (to benefit from the attenuation of the walls), turning the
transmitter power down on both ends (whenever possible) or using
attenuators (at least on one end) between antenna connector and
antenna.
jack
Travis Johnson wrote:
Hi,
We received our Vecima "trial" kit (one AP and five CPE) on Thursday
afternoon. We have not yet put it on a tower, as there were several
issues with their software on the AP... but here's some info thus far:
The base station is quite large. It measures approximately 14 inches
tall x 8 inches wide x 6 inches thick. It weighs about 25 pounds
(seriously). It has an RJ-45 ethernet connector and an N-male connector
on the bottom. (I was lead to believe they had omni, 90 degree, 120
degree and connectorized versions, and I requested the 120 unit, but
instead got this with an LMR jumper and an MTI 120 antenna).
We began by getting into the AP and making some "normal" changes
(downlink was set to 50%, so we changed it to 70%). Also the center
frequency was set to 3.410 so we changed that to 3.650. We also changed
to 7mhz channel size. We then applied and rebooted... and then we could
no longer get into the "radio" configuration page (where we had just
made all those changes). So we did a factory reset and tried again.
Same thing. We opened a trouble ticket with Vecima the next morning,
and they were able to reproduce the problem in their lab. Then about 3
hours later, another tech called back and told us we needed to upgrade
the firmware (even though the first tech said we were running the
latest). We upgraded and that fixed the problem... but then we had a
new problem. The "Allowed MAC address" file somehow got corrupted... so
they had to SSH into the base station and fix that file. (By the way,
this AP is just running Linux 2.6.14 kernel). We were now able to make
a connection to one of the CPE (after setting up the service
classifiers, service flows, and adding a service flow to this MAC
address). Making a link on our test bench (10 feet away), we had a
-55ish signal... however, the ping times and speeds were terrible
(2000ms and at the most 2Mbps). I am thinking it was because this is
running OFDM and in close proximity, the signals bounce all over. Last,
all three techs that I talked to at Vecima asked "Do you have an NMS
(network management server)?" and I had to continually say "no" and
then they would say "oh... I don't know how to do this manually". One
of the reasons we were testing this solution is that it did not require
their NMS to function... however, even their tech support is pretty
limited if you don't have it. Their NMS server is about $5,000 (but a
single server will support an entire network, with unlimited AP's and
CPE).
On to the CPE: This is one of the worst designs of a CPE that I have
ever seen. The entire unit is made by Tranzeo and looks just like their
normal 2.4 CPE. It has the bar of lights on the top showing Power, LAN,
RSSI, etc. The mounting bracket is the "L" bracket that bolts to the
back and has a U-bolt and clamp to hook to the pipe. The biggest
problem is how the ethernet cable connects. It has the white cover
plate that goes over the RJ-45 connector that has to be bolted to the
back of the radio... the problem is, the pass-thru connector is not big
enough to allow an already crimped RJ-45 cable to pass thru... meaning,
you have to run the cable thru the white plastic thing, then crimp it,
then plug it in, and then screw the nuts down holding the white cover.
If you ever have to replace the radio with something different, you
have to cut the cable and then re-crimp. Also, I can guarantee that
water is going to get into the RJ-45 as it is on the back of the radio
and the water will always be trying to get into the white cover and
then will just "flow" right into the RJ-45. I have attached a picture
that is 99% the same as this unit (except this unit is smaller than the
picture). The other issue is the PoE injector that comes with the unit.
This is the worst PoE that I have ever seen. I don't understand why
they can't use a grounded PoE that doesn't require a separate ground
wire. Use the ground built into the electrical wiring that is already
there (like the PacWireless PoE units). Attached is a picture of the
PoE that was supplied.
I will be testing the speeds and range this Monday (assuming the
weather is better... we got 6" of snow and 40MPH winds last night). I
will post more results as I have them. At this point, I am not really
impressed with a $4,000 AP that's just running Linux.
Travis
Microserv
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Jack Unger - President, Ask-Wi.Com, Inc.
Serving the Broadband Wireless Industry Since 1993
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