sources of interference.....

Hi all
Not sure what is going on with my last 2 installs. It may be that they are right on the edge or over the edge of the 60 degree spread of the AP. But, I wanted to hear from some more experienced installers before I hike up the mountain and “tweak” the AP towards those two customers. Here goes…

My preinstall came back nice. (Radios are 900 mhz. running 8.2.7 software.) 100% both up and down efficiencies. Power levels look good. Jitter fine.
This is from my truck to the radio. I run cable and then one moment it 40% efficiency then its 100% efficiency. Both customers had me run it along their satellite coaxial cable. The one customer had 2 lines and the other 3 coaxial cable for the direct TV. It runs along probaly 20ft of coaxial cable. Could that be the problem? If it is, how much separation should I be from the coaxial? 6" or 12"? I will be invesigating if they have any 900 mhz phones or baby monitors.

Now, if I was on the edge of the 60 degree spread of the AP would the SM exhibit that behavior?

Thanks for the help
Heath

our field tests on the 900 gear show an acual spread of about 110 degrees up to at least five miles

if you are using an integrated you might try a connectorized with a 14db yagi to get a more direct signal and a little more gain(2.5db) than the integrated

You should not have to separate the cat5 from the coax. When you did the initial testing you were in your truck (on the ground) next to the house? First I’d run a temp line from the SM to your truck so that you can use your own laptop and inverter to power up and test the SM in its current location. If it’s still a problem disconnect any of the customers cordless phones and/or baby monitors.

I don’t think that it is the issue here, but keep in mind that the LNB’s on sattv systems can cause interference with 900MHz. I’ve seen it before, and moving the SM away has been the solution.


I think you have interference issues elsewhere though. I’d move to a connectorized SM with a yagi, to help put more power in the direction of the AP. The integrated units are 60/60 beamwidth; 60-degrees vertical/60-degrees horizontal. A yagi will be much less than that, depending on the manufacturer and the amount of gain.

Thanks all. I’ll try to answer all the questions raised.

amd- The SM is away from the sat dish at least 30’ but the CAT 5 cable runs along the coaxial a good 20’ under the house. The AP are connectorized and the SM is integrated all moto canopy equipment.

jwelch- When I test I get up on the house and run a temp line to where I want to install it. Yeah, got my own power supply and laptop. Usually spend 15 mins running test and keeping an eye on the SM and AP. Yeah, I think Iam going to go do a walkthrough of there house today and see what they have as far as wireless equipment.

If there are baby monitors or a 900 mhz phone does it actually cause the SM to lose its connection to the AP or does it just make it really slow because of resends or both?
Thanks
Heath

can do both depending on how strong the signal from the baby monitor/phone is. it can decrease the signal enough to make the link test crappy or just make it to where it just re-regs over and over again

HHill wrote:
If there are baby monitors or a 900 mhz phone does it actually cause the SM to lose its connection to the AP or does it just make it really slow because of resends or both?


We've seen at least the jitter go sky-high and retransmits abound, but most commonly we see oodles of re-regs and in a couple of cases the radio's completely offline due to interference until the monitor or phone is hung up.

I went to the customers house sat there running test for 30 min. All link test come back at 99% to 100% in 2X. I get back at the office and run test then she isn’t on the remote subscribers list. A few seconds later shes there I run test and it comes back at 40%up. arrgghh.

So, ok Iam looking at the statistics page and the scheduler tab its saying in sync count 2936 and out of sync count 2894. whats up with that? Would that indicate interference at the AP? The dude that installed the AP’s didn’t use shielded cable! And every once in a while a bunch of customers will drop off then they will reappear.

I hope some one can help!
Heath
PS: all equipment running 8.2.4 software

this is sounding like self interference at the AP to me.

Either you do not have sync set up properly or you have another strong 900 MHz transmitter nearby.

HHill wrote:
The dude that installed the AP's didn't use shielded cable!

While it is recommended to use shielded for tower runs you can get by with any "outdoor" cable.

And every once in a while a bunch of customers will drop off then they will reappear.

Jerry is right, I think you have more than a single customer issue to resolve. I'd start t/s'ing the AP/BH installation first. Noise floor? Other equip. on tower? HAM's nearby? Feel free to share details of your deployment.

Thanks guys!
I guess I’ll start replacing the cable with shielded. Then run some spec tests. Contact the other wisps in the general vicinity.

That site we are using a “poor mans BH”. A 5.2 sm going to a 5.2 ap and there probably not even advantage.
The one we are losing customers (915) has 51 subscribers and the other (924) has 61. 924 is rock solid.
Well, I guess I’ll start the hike.

Thanks a bunch
Heath

Little update.
So, I did a spec anyl. and saw that there is another WISP out there on the same freq (915). 906 was clear so I moved the customers over to 906 and everything has been solid for 30 mins. yeah!

Ok, so I need to contact that WISP. What is it that we need to coordinate on? Control slots, max distance, sync and download %? Is that all? Now, I have talked to this other WISP up the hill and the owner said that that one WISP won’t talk to them and refuses to coordinate with him. So, can someone point me in the direction of any FCC documents that I can read regrading an uncooperative WISP. And what I can do.

Thanks for any info that you can give
Heath

FCC will do nothing.

Start with a friendly phone call. Let him know that you are probably causing him some interference and would like to co-ordinate radios to ensure you are both able to operate the best networks possible.

Follow up with a nice letter with the same friendly “were all in this together” type of language.

After that the gloves come off.

Well, the one AP 906 has been solid, now 924 is being super flakey. I presume the other wisp has started using that freq now. Ive tried calling them, no answer, can’t leave a message, mailboxes are full. I may have to stop by there shop next week. Or I may have to start swapping freqs around. If they refuse to change, coordinate or talk to me what can I do? The customers who are dropping had fairly weak power levels. If I can get there antennas raised up and hopefully get a stronger signal will that help?

On another note, can wisp’s operate without interference from eachother? There is another wisp who we have been trying to coordinate with (same control slots, same max distance and same up/down %) but he continues to get interference from us. Although, we have tried to coordinate with. He continues to say that its impossible. I think, that since his AP’s are on top of a mountain that is tolerance for interference is minimal. Meaning, his subscribers probably have power levels of high -70 or even -80. So, I guess Iam just curious if its true that 2 or 3 wisp can operate in the same area without interference?

Thanks
Heath

Increase the gain at the SM side.

Elevate the SM antenna
Use higher gain SM antennas
Use better AP antennas

Thanks Jerry.
Right now we are using connectorized 900mhz 120 degree horizontal radios. On freq 915 which is giving me problems. If I can, would using a intergrated 900mhz radio help? Since Iam new to all this what is ideal to combat interference. Having, for example, 915 pointing directly into the other 915 or have it back to it? Or does it matter? Or does the gain on the SM matter more. Right now the SM’s are facing the other 915.

Dumb question alert: Can I use non moto canopy SM with moto canopy AP’s?

Thanks

Thanks Jerry.
Right now we are using connectorized 900mhz 120 degree horizontal radios.

Which one?



If I can, would using a intergrated 900mhz radio help?

Since the 900 Integrated is 60 degrees it may not meet your needs.


Since Iam new to all this what is ideal to combat interference. Having, for example, 915 pointing directly into the other 915 or have it back to it? Or does it matter?

What is the "other 915?" the other operator? Why are your SM's pointed at his AP? I don't understand.


Or does the gain on the SM matter more. Right now the SM's are facing the other 915.

What are you using for antennas at the customer side? M2 17dB Yagis or Hyperlink 15dB grids are the best way to go.


Dumb question alert: Can I use non moto canopy SM with moto canopy AP's?

No. Canopy is proprietary.