BH20 fading away

Hello everybody, I’m new to this forum and, as usual, I start my contribution with a problem :slight_smile:

We have a link made with a pair of BH20, rock solid from three month: -54dBm with dish, power reduced emitting at 5dBm, 2,51 miles away. Full LOS. A very easy situation, I think.
During the day we have no fluctuation (55-53dBm) on power level.

Suddenly yesterday night we lost the link, and from cacti we saw that our signal was fading away under -80dBm in approx three hour.

We thought about an hardware problem or an aiming problem, so we changed one BH and then the other, check the aiming, but we haven’t resolved at all the situation.

Now We have: two new BH, emitting at -23dBm with dish, double rechecked the aiming (that was correct), but what we obtain is only a miserable -75dBm, with an enormous fluctuation: from -63dBm to -78dBm: now that night is coming, it’is slowing fading towards -80dBm, so I think we are going to lose the link again.

We also tried to change freq with no difference.
Where there is one BH (BHM) we also have 2 AP e 2 BH, and they have no problem at all. The BH (BHS) on the other side sees one AP with more signal than his master ( looking into AP Eval Data ), I can’t remember if it’s same power level of before all that nightmare

Any clue? :frowning:

what freq are you using?

try turning one of your AP’s into an SM and do a freq check and see what else is running. (this will only prove useful if your AP and BH are on the same freq)

if you are using 2 dishes at less than 3 miles try pulling one of the dishes off and only mount the BH.

depending on the dish you are going to have a very sensitive system.

we are working at 5.4GHz.

We made a spectrum analisys with the BHS, and checked that the freq we are using has a very low ground noise ( -80dBm). The AP are on same band, 5.4GHz, but more than 25MHz away.

We once had a problem with neon light wich automaticly was turned on at night.

You can try using software v 7.1.4 and see what happens.

does 7.1.4 support hardware scheduling?
with software scheduling we had problems with the amount of pps the bh can handle.

Something to note:

3 weeks ago were running 7.2.9 on all our radios (BH/AP/SM) and running HWS on everything. At that point our return times were around 65ms at 6 hops out. Last week we upgraded everything to 7.3.6 and still ran everything on HWS. At that point we noticed that our return times were now pushing 120ms at 6 hops out and peaking to about 140ms.

Spoke with Canopy support and they advised us that BH’s should be running in SWS not HWS. At that point we decided to switch a couple BH’s. We did one link and the return times droped from 20ms to 0.5ms.

We are now running a return time of 48ms at 6 hops out.

Just something to keep in mind.

Cheers
Brad

BlackTC wrote:
does 7.1.4 support hardware scheduling?
with software scheduling we had problems with the amount of pps the bh can handle.


No it doesn't. You don't need it. Software version 7.1.4, 3000 pps, 5.4 Ghz. You can do more with HWS?

Frothingdog…

What exactly did you switch? What did you change?

Vanilla

We upgraded from 7.2.9 to 7.3.6 on all our radios and that’s when our return times went through the roof. Switched just our Backhauls to Software Scheduleing and the return times came back down.

- All radios (BH/AP/SM) Running 7.3.6
- AP/SM running Hardware Scheduleing
- Backhauls running Software Scheduleing
* Several Towers colocating Backhauls with no issuse so for.

I assume most of you have read this. See this alert for info on the BH and 7.2.9.
http://motorola.canopywireless.com/support/community/viewtopic.php?t=1228
I also installed a 5.2 BH link last week and saw issues with HWS and latency. Running 7.2.9, turned on HWS and saw ping returns go up to 19-20 ms. Went back SWS and now I see 1 ms.


Aaron

original problem solved: almost incredible and very odd.
Wind has bent the base of the reflector 'till the link was made right through a secondary lobe, since re-aiming was not effective.
lesson learned:
1. when re-aiming, make also HUGE movement.
2. tell to the man on tower to super accurately look at the base of reflectors.


Anyway, it seems to me that everyone is suggesting to use 7.1.4 for BH. May be a problem having to syncronize 7.3.6 and 7.1.4?

thanks again to everybody

BlackTC wrote:

Anyway, it seems to me that everyone is suggesting to use 7.1.4 for BH. May be a problem having to syncronize 7.3.6 and 7.1.4?


No problems at all. On one site we have 6 advantage APs, 5 BH20 and one BH30, all BH20 run 7.1.4.