Wireless System design

[SteveD8]

All, Im new and this may not be the best place to ask but I know very little about designing wireless system but have been asked to source some detail and I hope you can help me. We have a power monitoring unit installed in a remote location (500m away) We are installing 2 wireless routers (we have chosen the AIR-AP1852i-Z-K9 units) which need to communicate over 500meters. We require 2 Directional antaneas but im not sure if we need the AIR-ANT2588P3M-N Dual Band 2.4Ghz 8dB1 units with 3 ports or the ANT2413P2M-N Dual Band 2.4Ghz 14dB1units with 2 ports.?

1) Whats the advantage of the extra port?

2) Whats the advantage of the Dual band over Single Band units?

3) What is the advantage of the 14dBi unit over the 8dBi?

4) What is the advantage of the 2.4Ghz over 5Ghz units?

and finally

5) Which of the above (Bands/dBi/Ghz) is the most important for selection?

If it helps...the data is not critical for operation, just monitoring and not a lot of data either.

Thanks in Advance

[Leo Laohoo]

If you want to do a point-to-point bridge and the APs will be mounted outdoors, I'd recommend either a 1540 or a 1562D.

[SteveD8]

Thanks leo, I just googled them and the 1560D is a great idea and saves buying and mounting the separate antenaes. Thanks

[pieterh · Accepted solution]

1) Whats the advantage of the extra port?
   the antenna is actually a combination of multiple antenna's  within the same housing.

   so a three port antenna has three internal antenna's and works best on an access point with three radio's

2) Whats the advantage of the Dual band over Single Band units?

   if the AP has dual band radios you can connect both bands with a single connector to the same antenna

   or x multiband radio's to connect to x multiband antenna's (in the same housing)

  for your communication example single bandwill suffice

3) What is the advantage of the 14dBi unit over the 8dBi?

   signal is radiated in a more concentrated beam, and sensitivity within the "reversed" beam is also higher
   so you can overcome a higher distance and still keep a strong signal
   with propper placement multiple antenna's will less influence eachother,

   for your setup the connection will be less disturbed by others

4) What is the advantage of the 2.4Ghz over 5Ghz units? 

    a) depends on the environment. 2.4GHz and 5GHz have their  own propagation in an environment with glass/ metal / concrete/ humidity

   b) 2,4GHz is more "polluted" with external wifi signals, 5GHz has more channels available to assign without overlapping coverage

5) Which of the above (Bands/dBi/Ghz) is the most important for selection?

   a) possible higher throughput of 5GHz is less important for your amount of data

   b) but 5GHz wil work fine in open space and you have the advantage to chose from a larger number of channels to have less interference

[Joseph W. Doherty]

Just to add to Pieterh's information, later wireless standards support "bonding" 5 GHz channels, so, in theory, you can create a wireless link with much more bandwidth.

[SteveD8]

Thanks Pieterh, most helpfull, I appreciate the time you spent explaining this