Re: [smartBridges] RSSI and LQ

George Mon, 25 Aug 2003 06:30:57 +0000

Maybe something to consider, maybe they are changing from one standard to another. Is it only FCC affected radios or is there others in other countries with the other standards failing also? George

Seeni Mohamed wrote:

The maximum transmission rate for the ETSI region is about 20dbm and
that is the reason dial-power option is disabled.

To achieve 5.5Mbps at 3KM, you need to use higher gain antenna (at least
14 dbi) which exceeds the ETSI standard. If it is a clear light of
sight, then the choice of the antenna is omni directional.  Sorry, no
idea about the mobileMark corner reflector.

In order to calculate for the ETSI standard on the  sB total units,
please select the appropriate outdoor devices (airpointPRO outdoor -
aPPT) and then select the 9dbi as the antenna gain.
The device TX output power = 11.5dbm(actually 11 dbm)
Gain                               = 9 dbm
When you calculate the wireless link, please include the fade margin
values also(Fading is caused by changes in the characteristics of the
propagation path with time).

Seeni, SB support

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Andrew Watkins
Sent: Monday, August 25, 2003 7:42 AM
To: '[EMAIL PROTECTED]'
Subject: RE: [smartBridges] RSSI and LQ

Seeni, Nish and Marlon,

Thanks for the replies...

With the aPPT and aBT, the dial-a-power tab is disabled when in ETSI, so
looking at the figures below, I'm 5db (or 25%) down before I start so
getting the Total products (as recommended by my supplier) for a link of
3km
here in the UK wasn't a good choice!

With the aPPO can anyone recommend a suitable antenna to ensure I get
5.5Mbps?  Would a aPPO and 9db MobileMark corner reflector at both ends
be
up to it?  The MM antenna have a 75deg horiz b/w so would an antenna
with a
narrower beam width do the job?  There are some power lines between the
two
sites but apart from that it is CLOS.

By the way, the tool to calculate the wireless link sets any Total
product
to a 13db gain antenna - not taking into account us poor souls in the
ETSI
region :-(

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Seeni Mohamed
Sent: 24 August 2003 17:01
To: [EMAIL PROTECTED]
Subject: RE: [smartBridges] RSSI and LQ

Hi Andy Watkins,

As per ETSI standard(UK) the maximum EIRP power is about 20dbm which is
equal to 100mW (Effective Isotropic Radiated Power - Power transmitted
from the antenna).
For the 3 KM distance, you will be able to get about 1Mbps speed rate
(aPPT and aBT using 9db antenna internally) and this is subject to the
noise, interference and environmental etc... The LQ values are
fluctuating means that there should be some interference or noise in the
wireless signal. Please try one by one channel to get better non
overlapping frequency. Or use any wireless network tool(sniffer or
airopeek) to find out the better non interference channel.

The maximum output power calculated as follows:
Device produces output power is about 11 dbm and antenna gain is about
9db = 20dbm(100mW)
Fade margin calculated as = 5 (assuming loss due to environment like
moisture, rain etc.) Below values are approximately as estimated values
and this may varies due to noise, interference or if the fade margin
increases.

At 1 to 1.5 km distance = 11, 5.5, 2 and 1 (Mbps)
   2 km distance          = 5.5, 2, and 1 (Mbps)
   2.5 Km distance       = 2, 1 (Mbps)
   3 Km distance          = 1 (Mbps)

Please use the following tool to calculate the wireless link.
http://www.smartbridges.com/showcase/link.php

Thank you

Seeni, SB support

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Andrew Watkins
Sent: Sunday, August 24, 2003 5:35 PM
To: '[EMAIL PROTECTED]'
Subject: [smartBridges] RSSI and LQ

I have been running some tests at ranges between .5km and 3km

At .5km the RSSI stays consistent at 100% and LQ is 98%.
At 3km the RSSI stays consistent at 40% but LQ fluctuates between 0% and
70%.

I am using the following:
aPPOTotal ----> aBOTotal
aPPOTotal ----> aPPO c/w 9db MobileMark corner reflector

As I am in the UK, the internal antenna on the Totals is 9db

Any comments on why the LQ is so erratic?

Thanks

Andy Watkins

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Re: [smartBridges] RSSI and LQ

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