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Powerbeam M5-400 (AP) and Nanobeam M5.22 (station) works better at feedonly ante4nna mode

by Monday

Hi there AIRMAX gurus,

I was quite surprised and confused because I have these multiple PtP links using UBNT and it apparently proves that feed-only mode (antenna setting on each equipment) works better in throughput and Arimax capacity than setting those same equipment on their corresponding antenna dish specifications.

Please see attached.

When I set the Powerbeam to FEEDONLY,Airmax Quality reaches 48% and station(NBE M5-22)  bandwidth reaches 40.5Mbps/6.5Mbps at Antenna Specs , but when Station is set to FEEDONLY (transmitted power reaches 26dBm).AIRMAX quality increases and bandwidth is better.

This is just confusing, why feed-only performs better than the specified antenna.

 

Thank youAntenna Gain Feed-only NBE-M5-22.pngAntenna Gain PBE-M5-400.pngStation NBE-M5-23 Antenna Gain.pngStation NBE-M5-23 Antenna Gain-AP at Feedonlymode.pngStation NBE-M5-23 Feedonly.png

Comments
by
Monday

By selecting Feed Only when you're using the parabolic dish antenna, you're possibly allowing the radio to emit more power than is allowed for the band.

 

You need to be very careful about exceeding legal EIRP on your networks. You can be subject to heavy fines/equipment confiscation/incarceration, depending on your location.

 

Select the antenna model you're using, and the firmware will help keep you within legal requirements.

by
Monday

Hi Flipper,

Your advise is well taken. But it makes me wonder how UBNT allow this "feed-only" option when there's no other antenna choice except the specified on the model. Would it be illegal if its there on the "choices"?

Thank you.

by
Monday - last edited Monday

It's illegal if the choice you make doesn't fit your antenna use, and that choice allows your radio to exceed the EIRP limits for the band you're using.

 

It is possible to use the radios without the dishes; that's why the 'feed-only' choice is there. Check the Quick Start Guide for the feed-only graphic illustration.

 

pbe400feed.PNG

by
17 hours ago

Hi Flipper,

Thank you very much for the advise.Thats an additional information I gained from UBNT's product line.

However, theres something that bothers me. If setting the antenna setting to FEED ONLY mode, how come it can stil transmit as far as 6Km? If we refer on the AZIMUTHS and ELEVATIONS of the Powerbeams/Nanobeams  antenna radiation pattern,with reflector antennas,what then is the RADIATION pattern for this FEED ONLY mode? it looks like forming a back lobes.

 

Thank you.

by
10 hours ago

It can transmit that far because you are still using the supplied reflector. You should only select the feed only mode if the reflector is not installed otherwise you are likely exceeding the EIRP limits. 

 

by
8 hours ago

hi, i can suggest you try to test under weather bad! with you own layout!, i think everything will go bad!

 

very sorry!  for my little bit english!