Antenna selection for MR76. ANT-25 vs. ANT-27?

SOLVED
BrandonS
Kind of a big deal

Antenna selection for MR76. ANT-25 vs. ANT-27?

Hello.  Can anyone help me understand why I would choose one of these over the other for use with a MR76 with the intention to expand coverage in a particular direction over a parking lot?  They seem almost the same from the data sheets.  And is it required to use two antenna per MR?  And is it ok to point them in different directions or are they supposed to aim the same direction?  

 

Last, I am curious if anyone knows if external antennas cause the MR to draw more power or not.

 

MA-ANT-25

vs.

MA-ANT-27

 

Thanks in advance.

1 ACCEPTED SOLUTION

Accepted Solutions
Bruce
Kind of a big deal

Re: Antenna selection for MR76. ANT-25 vs. ANT-27?

Hey @BrandonS, the difference between the two is that the MA-ANT-27 (Sector Antenna) is a more focussed beam. It doesn’t spread as wide an consequently has a higher gain in the direction it’s facing - so should provide greater coverage directly away from the antenna, but won’t spread to the sides as much. The choice all depends on the coverage you’re trying to achieve.

 

For the MR76 the top pair of connectors is for one 5GHz and the bottom pair 2.4GHz - might be the other way round, can’t remember - since it’s a 2x2 radio. So technically you can point the antennas in different directions, but obviously you then get different coverage for the radios (this can be useful for some mesh deployments). Don’t try and connect an antenna with one connection to the top and one to the bottom, that screws everything up, you need to connect to both the top connectors, or both the bottom connectors with an antenna.

 

As for not connecting to antenna ports, if you don’t want to use that radio you could, but make sure the connector has the watertight cover on it. I’d also recommend making sure that the radio is turned off, driving a radio transmitter with no antenna attached is never a good idea.

 

Different antennas won’t draw differing power. Antennas are passive, the reason you see different gains on them is due to the placing of the elements to achieve the desired radiation pattern. That said, some jurisdictions have limits on the radiated power (which is impacted by the antenna gain) so the access point may limit its power (with the smart antennas it knows what is attached), which in turn may impact PoE power draw marginally.

 

Hope this helps.

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1 REPLY 1
Bruce
Kind of a big deal

Re: Antenna selection for MR76. ANT-25 vs. ANT-27?

Hey @BrandonS, the difference between the two is that the MA-ANT-27 (Sector Antenna) is a more focussed beam. It doesn’t spread as wide an consequently has a higher gain in the direction it’s facing - so should provide greater coverage directly away from the antenna, but won’t spread to the sides as much. The choice all depends on the coverage you’re trying to achieve.

 

For the MR76 the top pair of connectors is for one 5GHz and the bottom pair 2.4GHz - might be the other way round, can’t remember - since it’s a 2x2 radio. So technically you can point the antennas in different directions, but obviously you then get different coverage for the radios (this can be useful for some mesh deployments). Don’t try and connect an antenna with one connection to the top and one to the bottom, that screws everything up, you need to connect to both the top connectors, or both the bottom connectors with an antenna.

 

As for not connecting to antenna ports, if you don’t want to use that radio you could, but make sure the connector has the watertight cover on it. I’d also recommend making sure that the radio is turned off, driving a radio transmitter with no antenna attached is never a good idea.

 

Different antennas won’t draw differing power. Antennas are passive, the reason you see different gains on them is due to the placing of the elements to achieve the desired radiation pattern. That said, some jurisdictions have limits on the radiated power (which is impacted by the antenna gain) so the access point may limit its power (with the smart antennas it knows what is attached), which in turn may impact PoE power draw marginally.

 

Hope this helps.

View solution in original post

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