2 900 on same tower

I now have a 900 Omni (yes I know omnis are bad) and a 900 Yagi both on the same tower. I do not have much vertical seperation between the 2 as this is a smaller tower servicing a small town. The yagi is to bring bandwidth in and the omni re-distributes it.

Just wondering what are the best ways to minimize self-interference. I have both set to Hardware scheduling. The are on channels 908.0 and 918.0. those seem to be the least nosiy in this area.

What else can I do? A GPS module would be nice, but I can’t really justify the cost for this POP as it is only servicing about 10 customers at the moment.

I know i could sectorize, etc. Howver, like I stated, this is for a small town and money is an issue. I can’t afford 3 120 sectors with 3 Aps. My ROI would be way too long.


Nothing wrong with the Omni, it’s a cost effective way to go. Obviously you want to use CPE antennas that are the same polarization as the omni.

Your channel separation is good. You have three non-overlapping channels at 906, 915, 924. Use the quietest freq for the AP.

No need for a GPS module, you can use the sync from the main tower. Just tie the sync on the RJ11 from the SM to the AP and your remote tower will be in sync. This is the remote AP method described by Moto and will make the most difference in your performance.

Also, in order to make sure you are not desensitizing the AP, make sure you balance the power output from each SM so that the power level seen at the AP is the sessions tab is 10dB above the noise floor and within 10dB of each other. For example if the noise floor is -80dB, then try to get each SM between -70 and -60 at the AP.

Thank you so much for the reply. It’s nice to get a helpful reply instead of people saying you need to sectorize, blah blah. It would be nice to sectorize, but can’t afford it.

I have been reading the canopy takes rj12 instead of 11. That correct? If so, when I get the right cable I just select sync on the timing port right?

thanks again,

Obviously sectors would be best, next would be horizontal omni, last would be vertical omni. that being said, if a vertical omni is meeting your needs, then it’s all good right?

They are 6 pin RJ11. Pins 1 and 6 are the sync. Yes, select timing port for sync on the AP.

well i have 4 omni’s 2 horizontal and 2 veritcal and the horizontal is by far the best choice but for sure do what jerry said about the power levels and make sure you separate the yagi as far as possible from the omni as possible. mine would drop out about 1 or twice a month.

if you cannot log in to it from the back side you will have to make a truck roll to reboot. Once i got around 25 customers on that type setup i started having alot more lock ups. not sure what it was but i finallly put up a couple of tranzeo’s and fixed it.

Info-Ed Inc.

you may also want to enable transmit frame spreading on the ap that is servicing the town.

this seems to be very important when you are using the same freq as the feed i have several 2.4’s that have worked for over a year and then when 7.3.6 software came out they started to get freq issues. the feed sm would drop out for no reason. i even tried rolling back to a previous version with no luck. but when i enabled transmit frame spreading on the ap all was fixed.

i am assuming it is something to do with the roll over to only hardware sched.

best of luck.