Ok, this is my first MikroTik so go easy on me. I am setting up a wireless AP. I have a Routerboard 433 with a Ubiquiti SWX-XR2 wireless card. I have them setup and working, but the problem is I cant get more than 50-100 feet away from the radio or I lose signal and cannot see the SSID anymore. The XR2 is connected directly to an N connector which runs up an 80ft tower. I am using LMR-400 to go up the tower. There is a splitter at the top which splits to 2 90 degree directional antennas. Am I missing something easy. TX power is set to default.

Did you ever calculate the loss on the pigtail, cable and splitter?
And with what did you check the signal?

I have not calculated the loss on everything. I inherited this system, and they wont let me climb the tower. I am told the antennas were working with an old cisco ap solution, and there was no problem with loss. I am checking the signal with a freqency analyzer. I have tried adding an inline amplifier to see if it is a loss problem, but it does not seem to have any effect.

Quick head calculation: 5dB cable loss, 28dBm output, minimal 2x 0,5dBm connector loss before splitter, makes 22dBm before splitter. devided by two (splitter) gives 19dBm on the other side of the splitter for each line. Minimal 2 connectors again gives another 1dBm loss and maybe another 1dBm for some short cable to the antenna leaves only 17dBm at the antenna.
Add the gain of the antenna (for example 18dBi/m) and and you have the power at the antenna. 35dBm output. Which should be noticable at km's distance.

But mayby you have tried to measure the output too close to the tower. Every antena has its working beam, not only in the horizontal pane, also on the vertical! Specially close to the antenna and right under the signal output can be very low. It might even be a 'black spot'. (The higher the gain of the antenna, the worse the signal outside its working beam!)

I suggest you try to pick up the signal at some hundres meters away.
If still not, maybe a bad connection in the radio-cable-splitter-antenna chain? One bad connector (water ingress, rust, poor manufactured connector) ruins the whole chain.....

I am told the antennas were working

Maybe you were told wrong?
Isn't this a bit like buying an old car and being told you are not allowed to look under the hood, but they tell you the engine is working just fine? So I think you're going to have to consider climbing the tower to inspect everything. As WirelessRudy says, you only need one bad joint somewhere (especially as it used a splitter/combiner) and that one joint can ruin everything.
When you connected up your pigtails onto the radio cards, they were pushed on ok and not damaged?

Thanks for the replies. I think you are right, there is a problem with the antenna install. Unfortunatley we will need to schedule a tower climber to troubleshoot. I am in the US, and we have all kinds of rules about tower climbing.

The UK is the same. Trust me, we have 'problems' with Health and Safety too! Of course, these rules are there for our personal safety, but....

Sounds to me like your measure you distance at ground level.
If so then you are most certainly overshooting, if it is at 80feet.
Is it a laptop you are testing with?

Find yourself a high building or mountain nearby (< 1km with laptop) and try to see if you can see the antenna's again. If yes, you saved yourself a climber, you are just overshooting at close range. If no, you can still arrange a climber to check everything.

Did you made the N-connectors fit to the LMR-400 cable yourself? Or do you use prefab? The last is usually tested and if the length is correct the preferred use. But often you need (or to save a bit on the costs...) to adjust the length of the cable to you needs. Meaning you have to put the connectors yourself. In this case google on how it exactly needs to be done. It is very easy to do it wrong, specially if you don't really understand what the purpose of the several parts of the cable and connectors are really mend to do. Creating a wrong connection that destroys the radio-cable-antenna chain is so much more probable than doing it right straight away. It definitely needs some experience and skills .... I have been there myself...

And to make things worse, you have at least 6 points of possible failure if we only look to the connectors.......

If this were overshoot, how come he can get a really good signal when he's right under the antennae, yet when he walks away it gets weaker and weaker? If it were overshoot, it would be the reverse in that as he got further away, the signal would start to increase but be very weak when he's right underneath the tower? Those sectorial antenna will always have some side lobes and RF going down towards the ground although they will be weak, the distance is small so they will still be picked up and as he walked further away, more sidelobes would be 'seen' until eventually he hit the main lobe and then the signal would really start to come up, despite the distance.

One problem here is that we really don't have enough data to decide! A quick long distance check from a high vantage point is a lot cheaper than paying for climbers and is therefore a very worthwhile thing to do.