900 mhz - Intermittent signal problem

Hello all, I am having a problem with an intermittent signal problem at my installation. The SM is set up with a yagi antenna and I have line-of-sight of the tower approx. 1.5 miles away, I also have a RSSI of 1300 and a Jitter -4. I am losing the internet connection sparatically, the SM can be seen by the tower and all of a sudden the antenna will be down. There is not set pattern of why this is happening. I have had the installation techs out to my house at least 12 times and the samething is happening. Anyone might know what is happening? Thanks!

Do u have a 900 mhz cordless phone?

Are there any power lines in the SM’s line of site? They will cause the signal to drop.

Q: Do u have a 900 mhz cordless phone?

A: No I do not have any type of device that runs on the 900 mhz band

Q: Are there any power lines in the SM’s line of site?

A: I do have a power pole and the line running to my house close but not directly in front of my antenna.

Power line could be an issue. Also check all phones etc. I have heard some 2.4 and 5.7 phones still use 900 in one direction.

How about a satellite dish? If you have a dish close the Antenna you will have problems.

I am having the same issues with 2 SM’s.

Scenario 1 -
1.26 miles from AP using 5.2. LOS is clear all except a set of high tension power lines that are in the middle. We are shooting over top of the wires only to the tower. Customer will be fine for 2-3 weeks straight and then all of a sudden their SM drops connection 3-4 times a day and does that for 3-4 days straight. Then they are ok again for another 1-2-3 weeks. it is sporadic! Any thoughts? I am sure you are going to say that the power lines cause this, is there any way around it?

Scenario 2 -
900mhz 1.06 miles from AP. No LOS due to living in a wooded area. Same type of scenario where the customer is fine for a week or two and then drops connection all day long. Up and down. No 900mhz phones in the house, 2.4 router is the only known thing. Funny thing is we tried to install his neighbor and couldnt get a signal at all. Homes are approx 100 yards apart. Do trees have a tremendous affect on the 900mhz at this close of a distance?

Also I have heard that you can tilt the 900 SM (one piece) SM’s horizonatlly and they will work. Is this true or a myth?

My sat. Dish is on the oppositie side and end of the house facing the exact opposite direction.

Move the SM to another location on the house - away from the power lines.

Scenario 1
Power lines will cause problems. With 5.2 you may never get a consistent link. It’s possible you might be able to blow through it with a reflector, but if I understand it right, you cannot use a reflector on a 5.2.

You might get a 900 to work being that close.

Scenario 2
I am guessing that your AP has an antenna that is vertically polarized. Either a 900MHz Omni “stick” or a Maxrad 8dBi panel turned sideways. I think this because you have other techs that are turning the integrated 900SM sideways ans getting a link.

I have SM’s 2 miles away looking through big Oak trees and getting a perfect link - even had to turn the power down on the SM.

I am having the same problems with one SM. Clear line of site to the tower about 5 miles away. 900 and a Yagi through the powerlines. No handheld phone system at all in the house or other usual types of interferance. We do have a Belkin wireless router installed at the home. The link seems to drop for no reason and with no set time. And sat dish is on the opposite side of the house. I can’t move the sm out of the powerlines as they run directly in front of the house between the house and the tower.

just a little note

over the last month or two i have had several flavors of routers dropping there contact with the sm and thus out to the blue cloud.

i have lowered the mtu settings on the routers and they seem to be working in most cases.

i see alot of failure in the linksys brand of routers.

Does the physical Ethernet link go down or will the unit simply stop passing traffic? I too have noticed this but only when the SM is terminated into newer Linksys routers. I have noticed a pattern when certain websites are visited, the port on the router will simply lock up. A reboot always fixes it, but is still a pain.

We have had some issues with the ethernet link as well. We turn off 100M half and full duplex in the SM and that solves it

i have just been changing out the router’s with dlink and for the most part everything seems to work.

i will try lowering to 10 base and see if that fixes it.

as i said above sometimes changing the mtu to a lower value works.

great forum…

Jerry, you mentioned that you have SMs 2 miles away through woods, perfect link, and you have the power turned down also. Did you get a performance increase from turning the power down? Here at Celerity, our 1.06 mile away SM is not working. I turned the power down on our only other SM which was .06 miles away. It seemed to work at first. Then a storm came in, everything is wet, and they are out of service again. I’m unimpressed by this 13 db yagi and I am going to swap it with a 15 db grid dish. We fluctuate between -75 and out of service which seems to happen at -82. The spectrum is full and 920 seems to work best for us. Our AP is an integrated panel.