constant re-reg and bouncing jitter

Hello all,

I am still somewhat of a newbie at this. I have a 200ft tower with three 900APs (all running 7.3.6) with 120 antennas. Land around is flat farmland - few trees. About a dozen customers on it thus far. No problems with any of them, even the far out ones (10 miles).

I have a new install that is 9 miles out. The last 1-2 miles nearest the customer is hilly with some trees. The link is definitely NLOS. Antenna and radio are mounted on the roof with the standard arm attachment. The first day it worked great. Now, I am having problems.

Here is the AP stats:

session count 231, reg count 62, re-reg count 2937
RSSI 1063/1045 jitter 4/4 power level -87/-88

SM stats:
RSSI goes from 1062 to 1105
Jitter from 4 to 11

I have the page update set to 3 seconds. Everytime it refreshes, these numbers are different. This SM is running 1X, software version 7.2.9 (I have not updated it yet).

Here is the output of a link test from the SM:

Stats for LUID: 7 Test Duration: 2 Pkt Length: 1522
Downlink RATE: 1734912 bps
Uplink RATE: 473088 bps
Downlink Efficiency: 100 Percent
Max Downlink Index: 100
Actual Downlink Index: 100
Expected Frag Count: 6777
Actual Frag Count: 6777
Uplink Efficiency: 100 Percent
Max Uplink Index: 100
Actual Uplink Index: 100
Expected Frag Count: 1848
Actual Frag Count: 1848

Can someone tell me what I need to change or check?

I know the software revs need to be the same. Probably wouldn’t hurt to add a little height to the SM. I don’t know a lot about the power levels yet…

thank you,


9 miles with no LOS is going to be sketchy, It’s impressive that you got a link.

What antenna are you using, or is this an integrated SM?

The antenna is an external stock Maxrad 9DB that comes with the starter kit.

Since you got a link with the 9db (really 8dB) Maxrad, I think that you may find that a 13dB Yagi directional antenna will do the trick.

A power level of -88dbm just wont last. Try putting a M2 17dbi Yagi on the SM. It would improve it a lot.

I have to agree with Matt, the 13 may be marginal, but the 17 would ensure a good link in poor weather.

Speaking of M2 17dB Yagi, just got mine in last week. Hopefully I can get around to benchmarking this antenna versus the 13dBi that I love to hate.

I’ve just about made the m2 14dbi antenna my standard, the 17 really is to darned big. You’ll get quite a bit of gain just by going to the 14, buy some of each and decide which one you like best.


We have used several of these antenna’s in our system and they are working great. Compared to a yagi the customer won’t notice them as much. They make them for 2.4, 5.7 and 900. These antennas have made my job easier. "when ordering make sure you tell them to include the mount and which polarity, horizontal or vertical.

I like the look of those antenna (wish they were higher powered). What kind of range are you getting using them? I have a couple of higher powered Yagis ordered to try out in cases like this one I posted.

I have a 10 mile customer, I am also 280 feet on a tower. I like using these instead of the Integrated because they are smaller on the 900mhz system. I believe they are cheaper too.

The 900 Stinger is an actual antenna with 10dB of gain. This is a little more gain than the Maxrad panel, is probably less prone to failure, and is a heck of alot easier to install. I would probably limit use to about 12 miles and clear LOS.

The 2.4 and 5.x are passive gain devices that we have used on customers that were marginal with no reflector. Slipping the Stinger on stabilized the connection.

OK. Small update on this. I replaced the Maxrad with a 13db yagi. The link immediately registered. Worked great all week. Now, all day Saturday, it has been dead. The radio is just reading “registering”. Thats all it does (I am getting that from the AP, since I cannot link up with the SM). Today, the re-reg count has gone up to 4300+. However, my sess count is 189 and the reg count is around 150. The power level is -85/-111.

It was strange. I had the Maxrad mounted on the standard arm. When I put the Yagi on it, I had to move it down to the very bottom of the arm (almost touching the roof) before it would register. Like I said, this is completely NLOS.

This has been a tremendous learning install for me (and still going). It appears to be possible to make it work, I just have not found the right combination/recipe.

Any of you experts out there have any suggestions?



You will need two people for this.

Put the SM into analysis mode and have your buddy reboot the AP. While the AP is off for that short duration, see what the noise floor looks like at the SM.

If its 88db or higher you will have link issues as you need a minimum of 3db above the noise floor to maintain a link.

Check that the power at the AP and SM are at max.

Confirm the SM has 2X disabled.

Get the yagi as far above the roof as possible. might take a telescopimg mast.

the noise floor at 915 is about -85. They did have a baby monitor that was on. turned it off. No 900 phones in the house.

Both AP and SM are max powered.

2x mode is disabled.

The only thing I have not performed is moving the yagi higher up.

Is there any chance all this could be caused by a bad ethernet cable? Or maybe one that works sometimes (if that is possible)? For instance, right now, I cannot access the SM from the AP even though it reports to be in session, and I have the correct number of SMs reporting to be registered on the AP. Last night I went up on their roof and attached my notebook. I had the move the yagi a few inches to get it to re-register. I watched it for more than 10 minutes - rssi avg. 1100, jitter 4-7. It held that, so I unplugged and went back down into the house. It would not register at all, just a constant loop of trying to then rescanning and resyncing. Every once in a while, the PC (A HP Pavilion) would say that the ethernet cable was unplugged but nobody had moved it.

This is very frustrating. I do not want to give it up, b/c it has worked for several days before dying.

Just to know I will test the cable…

Thanks all,


Bad Ethernet cable/crimp can be an issue as well as a bad power supply.

I think all you might need is a little height. With the link tests coming back 100 percent both ways.

As far as no 900 mhz phones a 2.4 or 5.7 can still intefere with 900mhz equipment. (2.4 and 5.7 still transmit or recieve on 900mhz i cant remember.)

I have also just started using double radius 17 db yagis as well. (Not only helps with stability but it helped drop my power level by an average of 3 db’s)

With the no register problem double check to see you have the right color code. A sm will not register without the proper color code. Also check to make sure you do not have “All ipv4” filtered in your sm page. I have done this before and it has worked for a little bit but then drops.

The only filters i use are PPPOE, SMB, SNMP, Boot P Server, ipv4 multicast, all others.

you did mount the yagi the right way didnt you? i have made that mistake and caught myself cause i use vertical and horizontal antennas.

yah - I have the Yagi mounted horizontally for my horizontal AP. The customer is replacing the power supply sometime tonight. Here is what my AP is saying about this SM:

LUID: 005 : MAC: 0a-00-3e-91-ef-8a State: IDLE
Session Timeout: 0, AirDelay 324 (approximately 9.02 miles (47628 feet))
Session Count: 7810, Reg Count 118, Re-Reg Count 7692
RSSI (Avg/Last): 1184/0 Jitter (Avg/Last): 5/0 Power Level (Avg/Last): -85/-110
DnRate(AP): 20000 DnLimit(AP): 500000 UpRate(AP): 20000 UpLimit(AP): 500000 (kbit)
LoUpCIR(D): 0 LoDnCIR(D): 0 (kbps)
Rate : VC 21 Rate 1X/1X

It is not acting normal at all. I have the SM rate limited, but it is not showing up. I also put the owner’s name on it, so it shows up in the sessions list also.

Does this mean it is not getting an Ethernet connection? It is receiving enough power to at least let my AP “see” it, just not register…

I would guess interference and high DB. I would probably try a little test like change the freq on the ap and the sm for a few minutes to see if there is better noise floor on the other freq. But i tell ya 9 mile in areas with high noise sometimes will not pan out.
Oh yea if it is grounded un ground it for a little bit and see what happens.I also seen something about a roof if it is metal i will put money on that being part of the problem.