Poor Coverage on ePMP 1000 non GPS

I purchased a ePMP1000 non GPS unit a while back to provide outdoor wireless coverage across an area of about 5 acres. When I first set the unit up it didn't have brilliant range across the whole 5 acres but it was certainly acceptable. Somewhere along the line though (without any changes being made) I noticed the coverage had become so poor that I could barely receive a signal standing only a few feet away from the unit. 

I figured it must have been interference but looking at surrouding signals with the analyser proved nothing. There was almost no interference that I could detect but I did have the same SSID set as my indoor network so I changed it, just in case. This made no difference either so I reset the unit back to factory defaults just in case something had gone astray there. Again, this made no difference to the poor coverage issue. I saw there was an upgrade to v3.5.1 so ran that but again, I still have very poor coverage. I have complete full and open line of sight for the most part so really confused as to why this unit was appearing to work adequately initially but has suddenly deteriorated. 

Any other ideas..?

Can you give us some details about the antenna, your tx power settings, and have you checked for a flooded antenna connection ?

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As Chris said, coax connectors that have not been installed correctly can cause issues by 1) causing the RF to refect back into the radio which will cause PA (Power Amplifier) to reduce power output. Not to mention what power is produced is not all radiated as some of it is being reflected back into the AP. And 2) can allow water into coax which can many times absorb PA power. Even properly installed connectors can allow coax to fill with water if not properly weatherproofed. 

Either situation can also cause the PA to fail over time which can lead to what you have now; very little coverage area even at close range due to no transmit power. 

Any way you could post pics of the AP, antennas, and connectors?

What kind of RSSI do connecting devices show?; and at what proximity to AP?

Also, cheap PVC and Fiberglass antennas can crack and fill with water over time giving the same issue of highly reduced range. Definitely do not use antennas from indoor soho routers on an outdoor AP.

If antennas are bad or coaxes are filled with water, or both, you will not see any interference that is near while in spec-an mode as it will also not make it to the unit's receiver.  

One last question, any lightning strikes near the AP? The EMF from a close lightning strike could have driven the front end of the receiver into the dirt. It may be deaf and can only hear very close units. 

Thanks for the reply - and all of the very reasonable suggestions. All things I might not have otherwise considered!

Here's a couple of pics. One is of the access point itself, the other shows where I'm having trouble getting a client to connect (with the access point visually highlighted with red). The total distance is about 50m and as you can see, apart from the grapevines, it's clear line of sight. The client has an RSSI of -81.

The screen shot shows the current setup.

The antenna's came with the unit - and I did remove and reinstall them just in case there was something as simply as a dodgy connection. No such luck. 

The lightning strikes are an interesting one. We did have some severe electrical storms here a few weeks ago but no close strikes as far as I know. I do seem to recall having the problems start well before this - though there may have been some earlier storms that I could have missed. Certainly no signs of any nearby physical damage. Is the only way to fault find that to replace with another unit...?

I am not fimiliar with those antennas. Maybe the Cambium crew or someone else has knowledge of them. I would imagine that they make a firm waterproof seal at the base of the connector and AP. Unless antennas are cracked, I doubt water intrusion is the issue. The connectors are also made into the antenna, so that is also probably not a problem. 

From the pictures you seem to be in a rural area which should mean it is interference free, or very little interference. That is unless you have wireless cameras, alarm relays, baby monitors, etc. near the AP. 

If you happen to have some antennas from an indoor router/AP, you could use those to see if that fixes your issue. If it does, then order some high quality outdoor antennas.You could also put a soho (indoor) router in this AP's place for testing and comparison. Besides that I can not think of any way to test the AP without test equipment. 

At 50m in the wide open with LOS you should have better signal depending on what type of device is connecting to the AP. At the same time a -81 at 50m is not the same as barely any signal at a few feet. Radio waves obey the inverse square law. If you have -81dbm at 50m you -should- have -75dbm at 25m; -69dbm at 12.5m; -63dbm at 6.25m; and -57dbm at 3.125m. Once again, low levels for the distances in open LOS conditions. This is also based on you being truly 50m from the AP. By the picture it seems you can not be much further, but pics can be deceiving.  

On another note, I would change channel bandwidth to 20mhz as it will give further range, and lessen the effects of any interference present. I would also change antenna gain to 5dbi or lower as this may allow AP to transmit at a higher power level (I know nothing about Australian laws). I would think those antennas are around 5dbi at the most.

Keep in mind, even if the AP could transmit at 10,000w, the system can only operate as far out as it can hear connecting units. This is where a good antenna system makes the system work. You may want to look at purchasing 2 good base station antennas such as Laird. For most base antennas you will need a coax jumper with N male connectors on one end and RP SMA on the other. 

Hopefully somone will know more about the antennas you are currently using and can throw their 2 cents into this post.