I am currently having issues with sm’s resetting from one of my towers. we are 600ft high with a 90.7 mhz antenna 100ft higher than our ap’s. We had to run all cables in conduit in order to ping the devices locally and the radiation gets pretty intense. We are using ntp to sync these ap’s and there are 18 customers on 1 ap. Does anyone know what threshold of interference this system can handle?
How many AP’s do you have on this tower? NTP will only sync the time of your logs. For clocking you will need to use a CMM as this uses GPS for timing the environment. What frequency are you using? Are you collocated with anyone else in the same band?
Depending on the noise levels from the FM array and the location of the equipment in respect to the array. One thing you should check is the wavelength of the broadcast Frequency. 90.7Mhz is closing up on the 10 foot mark so keep your cable runs away from the 10 and 5 foot intervals. E.g don’t use 300 feet or 295 feet for the runs. Try 296.5 feet for the run else your cable becomes the FM antenna. Run the cables on the inside of the tower same face of the strongest array. This is usually a null point for the broadcast. 100 feet of separation will usually work on a well-maintained FM site however it’s cutting it close. Try using ICE guards over the AP’s to shadow the RF. If you’re using 2 AP’s per leg then put a 2*3 foot solid ice guard directly over them. If all else fails you’ll have to put up a test AP and slowly drop it down the tower till the unit becomes stable. We’ve managed to run off 91.7Mhz. 100 feet separation from the FM array for the 5.7 AP’s, 150 for the Backhauls and CMM’s. We’ve also survived a year using non-sheilded outdoor UV rated cable. We’ve since switched to Sheilded though. Total Run length of the cable is 71.5 feet. We are currently forced to exceed a 150-foot separation from 97.7Mhz using Ice Guards on the 2.4 AP’s at another site. Each FM site is different in respect to TX and Noise. Each one has it’s own attitude. Separation and Power attenuation techniques should fix the problem; however some manual tuning will be required and perhaps loss of coverage due to mounting the AP’s at a lower height. I would try the Ice guards first!