Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

High Gain antennas and Ssid

             1. I've been having a discussion with my peer about client power requirements. We know the grayling a high gain antenna is used popularly in stadiums has 13dbi gain on 2.4ghz and 7dbi on 5. EIRP= Tx + 13dbi  - Loss(insignificant here), at the lowest Tx output, at the minimum you are looking at  25mW and will easily be pushing out 50mW. This begs the question that if the client max power is between 20-30mW how can it match or get back to antenna pushing out 50mW? RRM cannot throttle below 13dbi of your antenna.

2. Besides CCI and interference, what else would cause an SSID to fade in and out or disapper and reappear, when distance from the clients is not an issue?

3 ACCEPTED SOLUTIONS

Accepted Solutions
Hall of Fame Super Silver

Re: High Gain antennas and Ssid

In the early years of wireless especially in the 802.11b days, high gain antennas were used a lot without consideration for client power. Then with a\g, vendors started talking about tx power of clients and not to over power the client. So everyone did that. Now with stadium installs and outdoor mesh, who's right. If you want my opinion, I have always matched up power when possible. I have recently purchased a kit (wireless) for a shooting range and this transfers video up to 1000 yards on 2.4 using a 2.4ghz 300mW booster with a 9dbi gain omni antenna. I connect this to a Dell Mini9 with the internal 802.11b/g and also I have a Proxim USB 802.11a/g/n adapter and I can get video at 600 yards and send commands to the camera. They have video showing them shooting out over 1000 yards with this kit. So who knows:)

What else can make ssid disappear, too many other wifi around the area or even maybe high channel utilization and the device can't see the beacons.

Sent from Cisco Technical Support iPhone App

-Scott
*** Please rate helpful posts ***
Hall of Fame Super Silver

Re: High Gain antennas and Ssid

Yeah.... I'm going to experiment more with the camera kit.  I'm going to actually get an HD camera one of these days and see how well that works out to 600 yards (open) with just using my Dell Mini9.  The camera in the kit is just 640x480 and the resolution stinks.  This is the kit I have and I was even going to look at putting on a 500mW booster that can be powered up also via 5v usb battery storage.

http://www.bullseyecamera.com/

I have also seem many mesh systems that is set to full tx output on both Cisco and Aruba with no issues, and most of the users outdoors is phones and tablets.  Even in stadiums, the majority of the devices are phones and tablets and around and typically 40-60% are using 2.4ghz.  I had an emergency project with a client and we needed to bring up the environment quickly.  They had another vendor system that was really old so it started failing.  Well they temporally used the 1242's and also purchased a couple WLC's and 3602's and the external patch and omni's that work with the 3600's.  Well the WLC wasn't supported by the scanners so we used the dual band antennas on the 1242's and left the 1242's at 100mW.  Well the users said that the system worked faster than it ever did and this was not adding any ap's but swapping out the old vendors ap's and reusing the cable and connecting up the 1242's (2.4ghz only)  Ceiling was around 50' high and we used both omni's and patch antennas to shoot down past 75' in isles that were 6' wide.

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
Hall of Fame Super Silver

Re: High Gain antennas and Ssid

No problem... I did forget to tell you that these scanners with old firmware (didn't support lightweight per the manufacture with the firmware we were using) were also 10-15 years old that was being used in this warehouse/distribution/plant.  We did a walk through and I was cringing:)  They were testing scanning and were pretty pleased.... I was saying to myself.. WTH.... I guess that worked.  We waked each isle and they really didn't have any issues. haha  It was a good learning experience since this was an emergency project for me and I had to work with what they had.  I actually converted some of the 3602e's to autonomous and ran them at 20dbi also:)  So it was a mix of 1242's and 3602's.

Let me know if you do any other testing

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
7 REPLIES
Hall of Fame Super Silver

Re: High Gain antennas and Ssid

In the early years of wireless especially in the 802.11b days, high gain antennas were used a lot without consideration for client power. Then with a\g, vendors started talking about tx power of clients and not to over power the client. So everyone did that. Now with stadium installs and outdoor mesh, who's right. If you want my opinion, I have always matched up power when possible. I have recently purchased a kit (wireless) for a shooting range and this transfers video up to 1000 yards on 2.4 using a 2.4ghz 300mW booster with a 9dbi gain omni antenna. I connect this to a Dell Mini9 with the internal 802.11b/g and also I have a Proxim USB 802.11a/g/n adapter and I can get video at 600 yards and send commands to the camera. They have video showing them shooting out over 1000 yards with this kit. So who knows:)

What else can make ssid disappear, too many other wifi around the area or even maybe high channel utilization and the device can't see the beacons.

Sent from Cisco Technical Support iPhone App

-Scott
*** Please rate helpful posts ***
New Member

Re: High Gain antennas and Ssid

You are right, who really knows. I intended to experiment and document like you did with your video camera.  I've used high gain antennas in warehouses that had aisle 300feet plus long and 40feet high with a custom antenna 30 degrees azimuth and120 vertical, 6di on both band and the handgun scanners were able to get back.

Hall of Fame Super Silver

Re: High Gain antennas and Ssid

Yeah.... I'm going to experiment more with the camera kit.  I'm going to actually get an HD camera one of these days and see how well that works out to 600 yards (open) with just using my Dell Mini9.  The camera in the kit is just 640x480 and the resolution stinks.  This is the kit I have and I was even going to look at putting on a 500mW booster that can be powered up also via 5v usb battery storage.

http://www.bullseyecamera.com/

I have also seem many mesh systems that is set to full tx output on both Cisco and Aruba with no issues, and most of the users outdoors is phones and tablets.  Even in stadiums, the majority of the devices are phones and tablets and around and typically 40-60% are using 2.4ghz.  I had an emergency project with a client and we needed to bring up the environment quickly.  They had another vendor system that was really old so it started failing.  Well they temporally used the 1242's and also purchased a couple WLC's and 3602's and the external patch and omni's that work with the 3600's.  Well the WLC wasn't supported by the scanners so we used the dual band antennas on the 1242's and left the 1242's at 100mW.  Well the users said that the system worked faster than it ever did and this was not adding any ap's but swapping out the old vendors ap's and reusing the cable and connecting up the 1242's (2.4ghz only)  Ceiling was around 50' high and we used both omni's and patch antennas to shoot down past 75' in isles that were 6' wide.

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
New Member

Re: High Gain antennas and Ssid

Good info! Thanks for sharing

Hall of Fame Super Silver

Re: High Gain antennas and Ssid

No problem... I did forget to tell you that these scanners with old firmware (didn't support lightweight per the manufacture with the firmware we were using) were also 10-15 years old that was being used in this warehouse/distribution/plant.  We did a walk through and I was cringing:)  They were testing scanning and were pretty pleased.... I was saying to myself.. WTH.... I guess that worked.  We waked each isle and they really didn't have any issues. haha  It was a good learning experience since this was an emergency project for me and I had to work with what they had.  I actually converted some of the 3602e's to autonomous and ran them at 20dbi also:)  So it was a mix of 1242's and 3602's.

Let me know if you do any other testing

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
New Member

Re: High Gain antennas and Ssid

Nice work!

Hall of Fame Super Silver

Re: High Gain antennas and Ssid

I wish I had a space that I can test varius things, because at least your not stuck with one option, the option that in theory is right.  just keep us posted on your testing.

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

-Scott
*** Please rate helpful posts ***
264
Views
0
Helpful
7
Replies
CreatePlease login to create content