×

Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.

New WLAN install

Unanswered Question
Apr 10th, 2002
User Badges:

I am looking at installing WLAN to one of our outbuildings at work. I will be putting the transmitter/receiver on building roofs but due to traffic passing the link may lose line-of-sight for short durations (5-10 seconds).

Would this adversely affect WLAN operation?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 1 (1 ratings)
Loading.
jmassey Wed, 04/10/2002 - 04:41
User Badges:

Wireless technologies 802.11a and 802.11b don't require line-of-sight to transmit and receive data. I have wireless running in my home. Access unit is upstairs in a brick structure and I can connect downstairs outside of the brick structure (and anywhere else in my home). I have been very pleased but am still learning about the technology. Hope that helps, Justin

jtburgess Wed, 04/10/2002 - 06:03
User Badges:

I concur. Over large distances, there's something called a Fresnel Zone where the radio will sorta bend and not require line of sight -- so if a truck goes by you may never lose a packet. But even if you do lose a few packets, the 802.11 protocol will rettransmit up to 16 times by default (and this is configurable), and the higher layers (e.g., TCP) also may have retrainsmit timers.


Conclusion: not to worry!

blue.modal Thu, 04/11/2002 - 09:11
User Badges:


I can't agree with the two previous comments.


The vehicles passing by are made of metal. They will create reflected signals. You either need to get the antennas higher (plan on about $100 each for mounts that take a vertical pipe), or you need to go to circular polarized antennas.


Circular polarization helps overcome interference created by reflection of the original signal. I can explain why and help you find antennas.


Or, put the stuff in, try it and see if anyone complains.

abwahid Wed, 03/04/2015 - 14:47
User Badges:
  • Bronze, 100 points or more

Hi,

It is better if you mount your antennas on building top at maximum height where you think traffic would not

interfere between line of sight  communication.

It is very clear anything between the LOS communication may cause of signal loss.
 

Actions

This Discussion