Force 300 25 Ch0 way off

Hi all, I have a subscriber showing this…


On ch0 is this interference, misalignment or bad radio?

Unfortunately there’s only one way to find out really. Hope it’s easy to get to.

I hear you… Yes not a tough SM to get at… with interference or misalignment I have never seen this before. Thank you for your reply.

I have a pair of ePMP1k’s in a bridge and ended having nearly the same exact values as your post. Which would crop up in poor performance/packet loss and the only thing that would resolve it would be occupying another frequency. Oddly enough I would wait a day or two and things would subside and I could return back to the ‘problematic’ frequency and be within my typical -64/-63 range. It happens every couple of weeks for me which has me leaning towards possibly something nearby creating a problem. Yet I’m in a very rural region.

Be interesting to see what you turn up with.

Thank you for your reply! I will definitely post my findings/solution. This is a rural setting as well… 3000L is the AP and there are 12 SMs on the sector, all force 300 25. Did a scan and dont see any frequency issues. Customer is only using 2.4 on router. I will try another frequency just for the fun of it but as I was telling @brubble1 I have never seen what I posted above before when it was misalignment or frequency issues. I really appreciate the replies!

Also, this AP is really struggling with their GPS… I have new pucks coming from cambium to try…maybe that is the issue… will see.

This is the only SM with this issue on the sector…and other SMs on the same sector as the problem SM are within a mile or two of the problematic SM and chains are fine.

I have seen this issue a few times and a quick full power cycle of the radio has fixed it, rarely do we swap when this issue comes up but sometimesyou do so because the customer is basically demanding it. Funny thing is when bench testing to an AP 15ft away at -20db power, its fine, even when pointed out the door away from the AP. Since this level of disparityseems to only happen when its getting cold (when it can make up its mind to be cold) out, I am thinking its either frost or the radio switch chip doesnt like the milder cold.

Thank you for your reply… I had the customer power cycle antenna by unplugging the poe for 1 minute but still issue remained.

Hi @DigitalMan2020,

is there any chance to share the picture of installation? Is there a clear LOS?
The very last time I’ve seen such behavior it was some transmitting radio affecting side lobe of the AP subscriber was hanging on.
But all scenarios are possible. You should try to isolate it.

I don’t recall ever seeing anything that far out of balance that wasn’t a defective/damaged/water in one connector radio/antenna but I suppose an obstruction could do it if the radio was not only obstructed but also misaimed.

@brubble1 @aka The radio is definitely free from any obstruction in the LOS. It is up on a 35ft mono pole, the -66 signal is the signal achieved upon being installed a year ago… if it did go out of alignment I would of suspected the signal to show that… but I will be investigating today and will post findings. Thank you!

@brubble1 @aka

So swapped the antenna, still ch0 is way off like previous antenna, tried a different frequency and same results… help please lol

the chains are -84 on ch0 and -64 ch1, downlink snr is 22 and uplink snr is 29

Interference won’t make the signal weaker, just less usable. If you had -60s on both polarities but low SNR then you’d be seeing interfering signal - one polarity significantly weaker than the other is almost always something physical about radio placements or alignments, or a bad radio. GPS problems could lead to the entire signal being shut off at AP end, not a weaker signal. Force300-25 pretty much rules out antenna connections, and you’ve already replaced the SM, I’d suggest there’s something about the LoS or the alignment of one of the two radios. If you’re off toward the edge of the sector you can start seeing oddities just with that SM that are actually caused by AP alignment, most AP-end problems (antenna connectors, etc) would show up on most/all clients. The last time I saw this iirc was a customer installed at such an azimuth from the AP that the signal path was hitting the side of a 3ft backhaul dish beside the sector antenna.


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@nocotek @newkirk @brubble1 @aka @Douglas_Generous

Appreciate everyone’s help and support!! So the last thing tried should of been the first thing tried lol… alignment was the fix. Thank you all again, really appreciate it!


Thank you for final resolution sharing!

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