Help for the new guy....

I have just fired up my starter kit on a 105 ft. tower…I have three access points that are 900mhz and have 3 120 degree sector antennas hooked to those. I have a 2 degree downtilt on them. Not sure if the tilt thing is my issue or not but I cannot get a good lock on an SM at 2.87 miles out. I tried a 13 db yagi antenna and the panel antenna it came with. I have it set for 1x and I can see the AP at times but the link is very poor -85DDBM with a jiter of 9…What am I doing wrong? I thought I would get great coverage on 900 mhz…I live in a very dense wooded area. But the top of my tower is well above the tree line…Is my tilt messing me up? Should this be set to 0? Any ideas would be great…Also, would not mind talking to a few more experence members on the private PM or even the phone…Any help would be appreciated…I have not slept in 3 weeks now…


ClineC005 (New Guy)

P.S. I love the site…I have read so much my eyes hurt…

You will be lucky to get 1/2 miles in dense woods. Welcome to the real world.

Even though I am well above all trees? Would it help if I went higher on SM side?

Getting higher on the SM side would help if you got above the trees.

Dense woodlands can be an issue. More so when wet.

Did you run a coverage study using a program like Radiomobile to see what you might experience? Did you run a thorough spectrum analysis of the area? Perhaps you need to do both and then determine if you need more gain on the AP by using 60* sectors for 3 AP’s. Otherwise its 6 using 60* sectors.

What are you doing for sync? Are all three AP’s configured identically?

What is the max distance in the AP’s set to?

Is the power set to 26dB in both the AP and the SM?

Have you tried getting a link with a clear LOS?

Did you select US for the region?

Are you sure you have the Yagi polarity the same as the AP Antenna?

I do have sync via the GPS connection for CMMmicro.
I have the distance set to 10 miles on the AP’s.
The power is set to 26…
I have 3 indoor SM that are connected now that are with in a 1/2 a mile of the tower…
The region codes is set to US…
I am not sure about the polarity…I have the 120 degree sector antenna’s…I think those are Verticaly polarized…
As far as the yagi, It is a Maxrade 9 element antenna…It is mounted vertical as well…

Ok…I checked my paper work when I made it to the office…The sector antenna is a 120 degree vertically polarized antenna…

The yagi I was using is also Vertically polarized antenna.

Is there a setting in the AP to tell it what antenna? All I see is that it is a external conectoized…

You will want the elements oriented up and down. To get the best performance, you might consider M2 14dBi or 17dBi yagi antennas.

In areas with heavy foliage, you might try learning how to do tree installs (ask mattman). Otherwise elevate the SM’s on 25’ masts with guy wires.

The idea is to reduce the amount of foliage between you and the tower. One tree can suck up 3-6dB of signal.

I just ordered 3 new Horizantle polarized sector antenna’s…I will see that will lower mu noise floor level…

Trees are not a major issue in anything less then 6 miles. i have more then my share of links that are shooting through thick bush and i have more then enough throughput and a signal level of 68. i have had 0 problems with the 900mhz. its just a steep learning curve you need to learn what the radios want. you have the right equipment just play with it a bit once you get the first one like that rocking you will be solid from then on.


Thnaks! Do you use the Yagi Antenna’s? If so wich one’s? Are you using the Vertical Sector Antenna’s or Horizantle? Are you using the panel antenna’s that come with the system? I am hooking people up who are close to me with in 2 miles but really need to get furthur out…Thanks for advice and I will keep working on it…


You said your 120* antennas on the AP’s are vertical polarized…

And you said you are using the SM’s that are the indoor desktop units.

Those SM’s are horizontal polarized. Your AP is vertical polarized. If this is how I am understanding it, you are loosing 20+ dB of signal from AP to SM because of the polarization mismatch.

You need to get those HPOL antennas on there and you’ll probably see an improvement with that alone.

For external mounted antennas, you should look at Cushcraft 13dB yagi’s and M2 17dB yagi’s. If you must use a panel on the SM, someone here has suggested that a Mars 900MHz antenna is good (I think thats who they said they use??).

amd phreak wrote:
And you said you are using the SM's that are the indoor desktop units.

Those SM's are horizontal polarized. Your AP is vertical polarized. If this is how I am understanding it, you are loosing 20+ dB of signal from AP to SM because of the polarization mismatch.

There is actually a knob on the indoor units which switch polarity from horizontal to vertical and back to horizontal.


Didn’t know that! I was just going off of the spec sheet. :slight_smile:

true…and i haven’t seen anyone ask you to do a spectrum analysis. Have you identified your noise floor? Also - with 3 APs, are you using 3 non-overlapping channels which as i understand it are ONLY 906 915 and 924?

i am curious as to what type of antenna you’re using too - my recommendation at this point would be the 12.5 db MTI sector antennas that are 120 degrees.

We have some areas that we can get many many miles using 900 mhz (the trees aren’t as thick) and we have some areas that like they said we’re lucky to get 2-3 miles - unless we’re shooting OVER the trees to another region / area (in which case we’ve got 7…8…9 miles)

tree thickness is KEY. We’ve got one area not 3 miles from the tower that literally through an acre or two of thick trees no signal gets on the other side…it acts like an RF sponge.

good luck!

wow…lookee there. i’ve made 100 posts. that does mean i’m not a newb anymore? lol

Well, I just spent 5 hours at a lady’s house that is exactly 1 mile away from my tower. I could barley get here connected at -80db….She is exactly .95 miles away…Should I not be flooding that area with signal? There are trees yes, but not around this house. I also got on the peak of here roof which was very steep and could not connect any better….I have got to be missing something here that is really simple. I could see another AP 10.02 miles away and it kept trying to register to that AP. When I look at it in aiming mode my AP was there listed but it would still try to connect to the other AP 10.02 miles away, over and over again…Is there a setting inside the AP I am missing? I am well above all tress around me. I am 105 ft. in the air…As fare as what type on Sector antenna’s I am not sure… They look like a Fluorescent shop light with the cover on. I am still waiting for my Horizontal one’s to get here. I am just very frustrated now. Is there anyone out there that can give me a procedure of aiming and pointing? I am at a loss here….


nope…the 10.02 miles you thought you saw it registering to is YOUR aps…it will show the max distance (or al ittle over) while trying to register.

what frequencies are you using?

have you tried running ONLY the AP pointing in the direction you’re trying to install? (temporarily?) if your signal is vertically polorized and you were on her roof…using a yagi…like jerry said, make sure your yagi’s elements are pointed up and down, not left and right

  • Make sure that all of the frequencies are checked in the SM
    - Make sure the color code matches the AP you are trying to connect to
    - Check that the AP and the SM are set to United States and 26dB power
    - Don’t hold the Yagi past the mounting bracket - your body will attenuate the antenna by 50 to 90%

    I use Google Earth to determine if there are hills between the tower and the customer. It does not take into account foliage, however it gives me an idea of what to expect.

I wouldn’t spend any more time trying to connect a customer until you find out the noise floor on the tower and configure the AP’s correctly.

Set one AP to 906, second to 915, and the third to 924. Disable two and run spectrum analysis on each AP and post your results. All 3 should have the same max range, control slots, and downlink % and region set to US or other. You can set all color codes the same (good for SM roaming if an AP is down) or a unique number for each one.

Afterward you can stand a couple hundred feet from the tower and point an SM directly at the AP to test power/jitter.