Get this: 900mhz prob even with great signal/jitter/linktest

Our WISP has a 924mhz AP running HWS on 7.2.9 and about a dozen happy customers. But I did an install a few days ago with problems that didn’t make sense.

The user is only 1.78 miles from the tower; we’re using 900mhz due to trees. He’s got the 7.2.9 SM on top of his 1.5 story house. I did a site survey from his deck on the side of the house, everything was fine… signal around -70, jitter 1-3, registration seemed instant.

But after I had put the SM on top of his house, pointed at the tower, it wouldn’t register… AP Eval and Alignment gave me signal around -58, jitter 1-3; SA says nothing at all on the band except around 917-928mhz, around where our AP is. I swapped out the SM, thinking it was bad, but I got the same problem with the new one. Now it occasionally ends up registering, although it sometimes takes an hour to do so. After registration, the link seems completely solid. I think the only reason the link is registering now is that I’ve had it scan 924mhz only and I’ve tilted it up 20 degrees to reduce interference from ground level.

Before and after registration, signal is around -60, jitter is 1-3, both at SM and AP. Linktest is 100% all the time. I’d suspect interference if it wasn’t for the fact that it’s solid after registration and that the jitter is so low - I wouldn’t consider interference to be a possible issue at this jitter level.

Any ideas? I’m suspecting a canopy HW/SW bug because I’m out of ideas about anything else. I really want to get this working, I had to tell this customer to get rid of 3 of his cordless phones since they were 900mhz just to get this working on the deck without interference.

Thanks for any info.

is it near a satellite dish? I kid you not. Went through exactly the same thing, moved the SM 5’ and the problem went away.

Alternately ifyou are near power lines, you can have interference from that also.

If the above is OK, then try turning the power down.

I had already tried turning the TX power down without any result.
And there aren’t any power lines nearby that I can see.

This SM is near 2 satellite dishes, but they’re off to the side, farther away from the SM’s radiation pattern.

First thing I’m considering right now is moving the antenna on the roof anyways…

how far are the sat dishes? In the situation I had, the dish was behind the antenna and it still caused interference.

The LNBs on the sat dishes use high-frequency oscillators that I have seen disturb some radar detectors from a distance - it seems plausable that if they were close enough they could upset the electronics in the Canopy SM.


The sat dishes are about 4-5 meters away, at 2’oclock of the SM (12 o’clock being in front of the SM, towards our tower)

If you put the SM back on the deck, everything works ok?

If so, I’m guessing a bad cable -staple or a kink - possibly a bad crimp.

try swagging a known good cable up to it just to confirm. I keep a 100’ cable in the truck for just this type of thing.

Can you provide a Spectrum Analisis on the subscriber unit?

Do they have 900MHz FHSS wireless phone?

Had the same problem…Took the advice ande moved my SM 10 ft from the satellite dish and all began to work.
Thanks for the help.