Patrick, I was quite taken aback at the notion that RSSI wasn't needed.

RSSI is how you align a link.   Not SNR.   SNR alignment can give you a
misaligned link, where you're avoiding noise, rather than finding max
signal.

Either way, you need both...   Just can't do without both, can't imagine
even trying without both....



+++++++++++++++++++++++++++++++
neofast.net - fast internet for North East Oregon and South East Washington
email me at mark at neofast dot net
541-969-8200
Direct commercial inquiries to purchasing at neofast dot net

----- Original Message ----- 
From: "Patrick Leary" <[EMAIL PROTECTED]>
To: "WISPA General List" <[email protected]>
Sent: Sunday, September 24, 2006 10:00 AM
Subject: RE: [WISPA] vendor specs


If the general concensus is that RSSI is a must, then I will try to
convince PM to add such a reading.



Patrick Leary
AVP WISP Markets
Alvarion, Inc.
o: 650.314.2628
c: 760.580.0080
Vonage: 650.641.1243

________________________________

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Gino A. Villarini
Sent: Sunday, September 24, 2006 9:48 AM
To: 'WISPA General List'
Subject: RE: [WISPA] vendor specs



The problem with SNR for alignment purposes is that you are dealing with
a variable in noise, with rssi you work with fixed numbers.  I'm not
dissing SNR, it is extremely important, But for example, in order to
trouble shoot a link ... let say I install a Link and Im seeing a a SNR
of 6 on this link,how the heck can I determine if the antenna is miss
aligned or the noise floor is very high ???



Gino A. Villarini
[EMAIL PROTECTED]
Aeronet Wireless Broadband Corp.
tel  787.273.4143   fax   787.273.4145

________________________________

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Patrick Leary
Sent: Sunday, September 24, 2006 12:24 PM
To: WISPA General List
Subject: RE: [WISPA] vendor specs



Right, but the LED bar on the CPE can be used to do that. I mean, isn't
SNR more complete than just RSSI, meaning if your SNR is good than the
RSSI is by default good. Anyway, I have never heard of any moderately
experienced VL user say the units did not convey enough info to easily
establish a link and understand the quality of the connection. Consider
that with the CPE VL radio the LEDs will show:



WLAN link light-

*         Solid Green - Unit is associated with an AU, no wireless link
activity

*         Blinking Green - Data received or transmitted on the wireless
link, blinking rate is proportional to wireless

traffic rate

*         Off - Wireless link is disabled



Status light -

*         Solid Green - Power is available and self-test passed

*         Blinking Amber - Testing (not ready for operation)

*         Red - Self-test failed - fatal error



Ethernet light -

*         Solid Green - Ethernet link between the indoor and outdoor
units is detected, no activity

*         Blinking Green - Ethernet connectivity is OK, with traffic on
the port. Blinking rate proportional to traffic rate

*         Red - No Ethernet connectivity between the indoor and outdoor
units



SNR bar -

*         Red LED: Signal is too low (SNR<4 dB)

*         Orange LED: Signal is too high (SNR > 50 dB)

*         8 green LEDs: Quality of the received signal (green LEDs
translate per below)

LED 1 (red) is On - Signal is too low (SNR < 4 dB)

LED 2 (green) is On - SNR > 4 dB

LEDs 2 to 3 (green) are On - SNR > 8 dB

LEDs 2 to 4 (green) are On - SNR > 13 dB

LEDs 2 to 5 (green) are On - SNR > 19 dB

LEDs 2 to 6 (green) are On - SNR > 26 dB

LEDs 2 to 7 (green) are On - SNR > 31 dB

LEDs 2 to 8 (green) are On - SNR > 38 dB

LEDs 2 to 9 (green) are On - SNR > 44 dB

LEDs 2 to 9 (green) and 10 (orange) are On Signal is too high (SNR > 50
dB)



Mod level : Sensitivity : Min. SNR (this chart for 20MHz channel)

1 : -89 dBm : 6 dB

2 : -88 dBm : 7 dB

3 : -86 dBm : 9 dB

4 : -84 dBm : 11 dB

5 : -81 dBm : 14 dB

6 : -77 dBm : 18 dB

7 : -73 dBm : 22 dB

8 : -71 dBm : 23 dB





Patrick Leary

AVP WISP Markets

Alvarion, Inc.

o: 650.314.2628

c: 760.580.0080

Vonage: 650.641.1243



-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of G. villarini
Sent: Sunday, September 24, 2006 8:48 AM
To: [email protected]
Subject: RE: [WISPA] vendor specs



Patrick,



Rssi is very important to determine if a link is properly aligned and
its achieving its link budget.



Altough we don't use alvarion(yet), we are currently researching
backhaul options and the way we comission ptp links here is that we run
the calcs on radio mobile and spreedsheet to determine the link budget
in advance to implementation.  Snr won't help much there...



Gino



-----Original Message-----

    From: "Patrick Leary"<[EMAIL PROTECTED]>

    Sent: 9/24/06 11:32:47 AM

    To: "WISPA General List"<[email protected]>

    Subject: RE: [WISPA] vendor specs

      Brad,



    Software controlled dual polarity might be nice. Not sure why you

    consistently harp on us though since no one else has it either other

    than your longtime preferred vendor.



    I am not as convinced about your complaint about RSSI. Is it just
used

    to RSSI like being used to feet in stead of meters. But also, isn't
RSSI

    less sophisticated and a less useful number than SNR since it is
only an

    indication of receive signal without discounting noise? SNR provides
a

    more accurate representation of wanted signal since it discounts for

    unwanted noise.



    Not sure of your complaint about the RJ45. No one else remarks about
it

    and we don't have issues with water intrusion. In other words, it
works

    well. If the opening was enlarged you increase the potential for
water

    intrusion.



    Following the color code? Yes, as an old cabling guy, I would agree.
But

    I am pleased to note that one is really running out of things to
harp

    about when one continually highlights this a major deficiency.



    So now that I have responded here to your public mail, will you
please

    admit that even if the VL came to life and saved your kid from a
flood

    you complain that it was not fast enough and that it ripped the
kid's

    clothes. I wish some day you'd accept that your customer chose VL
and

    you should take the opportunity to learn about it instead of still

    trying to make it fail so you can get them to switch to Trango. Even
the

    best radios will have room for improvement and every decent brand
should

    have something special that differentiates it. You work so hard to
find

    fault you miss opportunities to become proficient in more than one

    brand. So accept our invitations to allow engineer visits and accept
our

    invitations to be trained. Know what I mean?



    Patrick Leary

    AVP WISP Markets

    Alvarion, Inc.

    o: 650.314.2628

    c: 760.580.0080

    Vonage: 650.641.1243














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