Weird RF issue

We have a strange issue going on that happened at 3 installs in the past 2 weeks. We have a 6 AP cluster mounted on a round water tower approx. 140ft agl. When we do an install at the customer prem approx 2 miles away with clear los 14ft agl the link would barely connect. We dropped the SM down 10 ft and had a beautiful signal. Going 10ft down increased the signal by at least 15db and dropped jitter from 3-4 to a solid 1 on 3 different occasions. Can anyone offer an explanation about this?

Sounds like a strong early reflection off the top of the water tower causing vertical multi path. You happened to be in the null. Moving down put you back in the lobe.

What freq, and how far off the top of the water tower is the cluster mounted?

It’s 2.4Ghgz. The cluster is mounted approx 4.5ft off the top of the tower. It’s in a temporary spot until we finish our transition from our old equipment to Canopy. Once we have everyone switched over I plan on lowering it a little and also adding a little downtilt since our farthest sub. is only 6.2 miles out. I may use the canopy cluster mount from Tennadyne, has anyone used this mount before? I was thinking it may be interference from the other system operating 45Mhz away, but I don’t think interference would cause the db fluctuations that we have seen. The first time it happened I passed it off as some stange rf something or other but after the 3rd time I am beginning to wonder.

The Tennadyne mount can be found below. … ochure.htm

I would suggest raising it from 4.5’ to 10’+ and use a little downtilt.

Thanks Jerry.

Hey all,
I am the installer on those 3 ‘weird RF’ situations that Meister was concerned about.

the first 2 instances there was a 10 dB difference when dropping only 3 feet. The third was worse… no registration at all (1.86 miles) LOS…no reflector
10 feet down… -58 dB.

The only reason this concerns me so much is not for new customers… i will have to test anyway…but for the upgrades that i am doing with existing customers. If anything my initial install might need to be elevated for better LOS. Frustrating…


Thanks for your help Jerry,