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Regular Member
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Registered: ‎01-05-2013
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PBE-5AC-500 Feed Horn/Focal Point/Radome issues

We just installed a new PBE-5AC-500 dish and came across a very strange issue. When aligning to my 13dbi omni at about 3.5miles, perfect LOS at about a completely level plane with the AP, I am unable to get the chains even. The best I could get was about a 12dB difference (71/83).  Mind you, I have installed over 1000 radios and I am pretty good at aligning dishes. I know something is wrong because I have another connection about .5mi down the road closer to the AP with PBE-5AC-400 @ 66/66 signal off the same AP and in the same line from the AP to this new radio. This got me thinking that something is off on the focal point of the feed horn or something. So I proceeded to try to remove the radome cover, which BTW is a PITA when its hanging off a tower on a windy day. After some blood was shed removing the cover, I checked the signal... Just by removing the dome the signal improved to about 69/77 without doing anything else, which I thought was strange as well. So then I though, I will reaseat the feed horn. Boom now I'm at 69/73. So i pushed up/down/left/right on the horn a little, it moved a bit in the socket and now I'm at 68/70 with it in the best position i could find. I then thought, maybe my alignment on the whole dish is off just a couple degrees, so I tried to re-align again. Still the best I could get was 68/70 which I am ok with, but it seems like the play in the feed horn socket could be the main issue. I snapped the radome back on and lost another 3dB on the one chain again which I find odd as well unless snapping it on caused the feedhorn to move again.

 

When checking the feed horn, it has a lot of play in the base socket that it sits in, in the dish assembly with very little trouble moving it. Like 2/3degrees in any direction different. This can cause a huge issue if the focal point is off that far. I believe these are some older/early production units (2015?), could there have been a manufacturing issue? The snap together parts were very hard to get to snap in. I had another pair of them that were the first I installed a couple years ago and those seemed to exhibit the same issue but I got the horn in the correct position for the best signal and they have been fine ever since then. 

 

Has anyone else experienced issues with the PBE-5AC-500 dishes? I have had some strange things with the 4 now I have installed that I cant really explain other than quality control issues with the snap together parts.

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Re: PBE-5AC-500 Feed Horn/Focal Point/Radome issues

You may have a bad unit there. @UBNT-James Can you please investigate?
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Re: PBE-5AC-500 Feed Horn/Focal Point/Radome issues

@bchur83 

 

Were these units previously installed somewhere else?

 

Is there anything on the radome like stickers or has it been painted? 

 

Based on your description, I think we should get these units back for inspection and replace the feeds/antenna.

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Regular Member
Posts: 360
Registered: ‎01-05-2013
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Solutions: 21

Re: PBE-5AC-500 Feed Horn/Focal Point/Radome issues

They were brand new out of box but they were a set of spares for the original set we installed a while back, so I think the test date on them is somewhere in 2015. There is nothing on the radome other than the Ubiquiti Logo that comes on them.
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Re: PBE-5AC-500 Feed Horn/Focal Point/Radome issues

Our installers keep telling me the new pb 500 AC do not perform anywhere near as well as the older ones with the single bracket. I have not dug into it heaps but they often say they may only get 1 db advantage.. new bracket is good though.
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