reg fail

I’ve got a new 900 AP. The first SM I’ve tried to install is 1.82 miles away. The signal strength is -68, jitter is 4, but the reg fail clicks up one every couple of seconds. I think it’s interferace causing the problem. It’s registered a couple of times for half a minute or a little more. I was just wondering if someone with more experience that me had any ideas. Thanks!

Well, if you’re able to make a registration at all, then the settings must be consistent between AP and SM. Best bet would be to run the Spectrum Analyzer on each end to check for your interference. Probably want to only have one piece of equipment (AP or SM) on at a time so you aren’t just detecting yourself. You can boot the AP up in SM mode and run the Spectrum Analyzer from the Expanded Stats. Even though your problem is registration, I’ll go ahead and add that you will lose registration when you Enable the Spectrum Analyzer, so run it locally or you will lose connectivity (even though the analyzer will automatically shut off after 15 minutes). Also, in case you didn’t know, either set the device to auto-update every 5 seconds or so, or click Enable to update the reading. Hope that helps…

Take screen shots of the AP and the SM config screens. Post them on a blog or a server and link to them here.

here’s the screenshot of the ap config. I’ll get the SM config later this morning. Thanks for looking at it.

Here’s the SM config. Thanks again.

On the AP
It’s not necessary, but you might want to set the webpage auto update for 3 to 5 seconds. This refreshes the page automatically.

Unless there are other 900AP’s that are not in sync with your system, disable Transmit Frame Spreading. We have 3 900’s and we don’t need Transmit Frame Spreading.

This all looks good. Did you do a spectrum analysis of 906MHz? You can set the AP as an SM, and do a Spectrum Analysis. Choose the quietest frequency available.

Thanks for looking at it. I had disabled frame spreading during troubleshooting. The spectrum analyzer in the SM and AP show pretty high noise, but when we run a separate spectrum analyzer, a bumble bee, it’s much lower. I guess I know which analyzer to believe. We’re going to get the antenna up another 20 feet tomorrow, so we’ve got our fingers crossed.

When you say the noise was pretty high, just how high?

Turn off your SM when doing the analysis.

Try testing at 906, 915, and 924 and see what frequency gives you the best performance.

Are you using a vertical or horizontal omni? Most 900MHz RF is vertically polarized, this is why Moto went with Horizontal.

I had everything off when I ran the analysis from the AP. I’ll post a screenshot from the SM in the morning. This is a 120 vertical polarized. I was under the impression that Motorola’s itegrated antenna was vertically polarized as well.

I forgot to post the spectrum analyzer’s readings.

Nope, the integrated antennas are Horizontal - that’s your problem.

2 choices,
1. Change the AP sector out for a Horizontal Antenna - best option

2. Go with connectorized SM’s and use yagi and panel antennas that can be rotated 90deg for Vertical Polartization.

"We’re going to get the antenna up another 20 feet tomorrow, so we’ve got our fingers crossed."

Height is a double edged sword and I generally try to keep my 900 MHz gear as low as possible to reduce the impact hearing distant 900 MHz sources.

Assuming you have other customers on this AP, then I would try moving around the perimeter of the customer’s house. I anticipate that they or a neighbor have a strong 900 MHz noise source and height won’t help, but blocking it by moving to the other side of the house can be effective.

Good thing for me, I’m not using integrated SMs. I went back to look, and I can’t find any spec on the polarization. That’s why I assumed they were vertical. Can you point me towards a complete spec sheet on those? They would make a nice sectorized AP now that I know they’re horizontal, but they’re too heavy to use for SMs, that’s why we didn’t buy integrated in the first place.

Looks like that noise floor is down around -95dB so that’s not too bad.
I’d stay away from that 910MHz unless that’s you.

I think it’s your antenna polarization.

You need to strike a balance between elevation and ground clutter. As quiet as the area is, you could elevate quite a bit.

What is the Analyzer program you are using? Looks like it’s software based. What did it cost?

I don;t know what you are using for the AP - you would need to check with the manufacturer to confirm polarization. If it was 1200 bucks or more I’d wager it’s Horizontal, but check on it.

The polarization on the 8dB Maxrad panels are marked with an arrow.

For yagis, just turn them 90deg to change polarization. Elements = polarization.

Yikes! i just looked at the AP Spectrum Analysis - that’s very very bad.

The only usable channel is 920.

Now, if you have a Vertical antenna on the AP, you will see dramatic reduction by going with a horizontal antenna.

Jerry Richardson wrote:
For yagis, just turn them 90deg to change polarization. Elements = polarization.

Are you saying that you want to mount a Yagi for 900MHz canopy with the fingers horizontal instead of vertical?

I recently bought a 14db Yagi which I thought was made specifically for the Canopy stuff, and the mast mounting on it orients the thing with the fingers vertical. So do I need to modify the mount to pivot it 90 degrees before I install it?

(Yes, I'll admit to being a neophyte who has never used a Yagi in the past...)

Here’s the link for the antenna. Pretty sure it’s vertical.

Yes, rotate the Antenna so the elements are aligned horizontally (assuming your AP is using a Horizontal antenna)

That’s a pretty nice antenna. Too bad it’s vertical.

That’s a big reason the noise level is so high. If it were Horizontal, it would likely reject alot of that vertically polarized noise (possibly by as much a 6-12dB). However, that is not a guarantee.

With -75dB of background noise (as far as the AP is concerned) you will need to be able to have every link be -65dB or better. This will limit your effective LOS range to about 8-10 miles when used with a 13dBi Yagi and about 4-5 miles with an 8dB panel.

With foliage, the range might be a couple miles at best.