900Mhz Jitter and interference

I have a pocket of about 20 customers on one 900Mhz AP in a heavily treed area and most of them have good connectivity all the time. But there are 2 customers that experience extremely high (12-15) jitter once every few days that lasts 4-5 hours then returns to normal. These customers live about 200 yards from eachother north to south and the AP is east of both locations (one customer is 800ft from the AP and the other is about 1/4 mile from the AP). one is on a 9DB yagi and the other on a 14DB yagi external antennas. there is an oil pad to the west of both locations and I have read about scada transmissions causing interference. Both radios are about 10ft off the ground. My question is: would interference from the scada transmissions manifest its self in Jitter? I also notice that during the high jitter the power level drops 7-8DBm in each radio. Another factor is that the most recent problem occurred during rain though I wouldnt be very quick to say that was the problem since its not a global problem and i dont think 900 is subject to atmospheric conditions. But this is my first 900Mhz deployment so I am way open to really ANY input on desired power level range acceptable Jitter and RSSI values in general for a 900Mhz radio.

FHSS SCADA will crush Canopy 900. It used the entire spectrum at max power unless the configure it to use only part of the spectrum.

Jerry Richardson wrote:
FHSS SCADA will crush Canopy 900.


We were on a water tank with the county running FHSS SCADA in VPOL. Were were running HPOL andsome customers were still having problems. thankfully we worked out a deal with the county. But SCADA will hurt. BAD.

Sounds pretty bad…right now I am using the top of the band (924) and because its only these 2 customers out of the 20 if it IS scada vpol i am in luck because we are running hpol what i am doing next (now) is moving to the bottom of the band (906) to see if I can get away from whatever the interference is. Its kind of a lazy approach with out actually going back out and doing a spec analasys.
Lets say for a moment that it is not scada. What about frenzel zone issues say if the yagi sits 6-8 inches from a wall to its right but is 12-24 inches from the eve line of the roof? wouldnt the jitter be crappy at a more consistant rate then? or would it still be every couple of days for just a few hours?

thnx for the replies on this

Well that was interesting…varied results on different channels 906 resulted in one lost registration but looked the best in the aim statistics 914 resulted in only 4 successful registrations 910 resulted in 8 successful registrations and 911 resulted in all successful registrations with good aim stats in all the radios since there is one AP i have isolated to 911 for now by only checking that freq box in all the SM’s. pings to radios still look normal power level rssi and jitter all look OK!

Keep in mind that the 3 non-overlapping channels are 906/915/924.

so it is similar to 5.2 in that way…I would appreciate any links to documentation or user manuals on 900 so that in the future i dont get blind sided by info like that. u may have to forgive my ignorance a little (or not if u dont want to ) as i was kind of tossed into the mix on 900 without much research done on my part so any n00b documentation that anyone can provide me a link to would be greatly appreciated as canopy’s support site proves to be somewhat of a labrynth

PS my radios have been up on 911 for 24 hours now so thats good but the test will be to see if i dont get any calls for a few days based on how intermittant the outages are

moved to 922 and on and on but knowing now what i know about PINE TREES it seems the only solution is perhaps a small controlled burn. After cooperating with a great customer over a few weeks and having the opportunity to do a lot of spec analysis we found that when it rains the connections in heavier trees fade out even one that is only 800ft from the ap. does anyone think that switching from Hpol to Vpol would help anyting? (like shooting between trunks of trees instead of across them)