Hello All,
I have an XR9 system on a tower hooked to a 12dbi pac wireless horizontal 120 degree sector. My noise floor has always been somewhere in the -90’s, usually around -93 or so. All of a sudden the noise floor spends most of it’s time around -80. I spent the past 2 days driving around the tower looking for sources of interference and found nothing obvious.
I do have a couple questions… does anyone know how much power is required within a certain range to cause the noise floor to get that bad? I’ve tested with cordless phones and other various things before and usually if you’re more than 100 feet from the antenna, I don’t see any noticable change in the readings… I’m not aware of any new cell activities and driving around the rest of the towers around didn’t show anything…
That’s leading me to believe that maybe the card is failing… We did have very high winds the past few days but I’ve only heard of that affecting people with ungrounded omni’s. Do the symptoms seem like anything anyone has seen from a failing card? The card is 150 feet up the tower and wind chills have been in the -20f range so I’m putting a climb as one of my last resorts in a couple days when things warm up a bit..
Around here, I have to deal with one cellular tower just below 900MHz, drops the noise to about -85 on SR9, at 930MHz, Alabama Power has all of its subs tied in on that network for monitoring. I don’t know how much trouble they cause tho.
One thing that I’m not sure of is if a cavity will help me or not… When I do a scan in 3.3, it reports noise floors of -80’s for 907, -70’s for 912, -60’s for 917, and -80’s again for 922. So it apears that the majority of the noise is around 917, and if I’m understanding things right, the lower UBNT cavity filter at 912 wouldn’t even block things out at 917.
Does anyone know of a cavity filter like the DCI ones that are 5.5 mhz wide but don’t cost 600 freaking dollars?
if the noise is out of band then and as noisy as you say then the DCI filters work amazing. I sectorize with sr9 and found that with 5mhz spacing adjacent channels spill into each other, so the filters really clean up and provide performance gains rather than using a wide channel filter. Drawback to the dci 5.5 is you have to cut the tape and put in a different filter if you need to switch channels.
Get a good spectrum analyzer and look at the spectrum closely before you make the investment.
Yeah, I’m trying to get ahold of a few of the Ham radio guys in the area that might have spectrum analyizers… that would answer a lot of questions. If I can get my hands on a filter, I’ll give it a shot.
Just as an update, I swapped out the XR9 for a new one and the noise floor is back at -96 (no filters at all and I didn’t change anything except for the card.
