LTU Rocket and WS-12-400-AC

[monty1157]

Hi All,
For a good few years one of our sites has ran a Rocket AC sector from a WS-12-400-AC switch with absolutely no problems. We upgraded the sector and CPEs to a Rocket LTU just over a week ago, and since then I've been getting odd crashes and restarts from the LTU unit without any reasonable explanation. I've taken a look through the internet and it was mentioned that these units can run on 24V, but have been designed to run on four pair 24VH and that this may resolve a number of unintended unit crashes and reboots. However, the only thing I can find on here is only run them at 24V for short distances or 48V for much longer cabling distances, never 24VH. The length of the cable run is around 45m at the very most.
If anyone would be kind enough to please give me the correct voltage settings to power this unit, I would appreciate it. The last thing I want to do is change the voltage to 24VH and make a mistake that will end up costing me a lot in time and money, but especially time.
Cheers,
Mark

[Omniflux]

In this thread, someone reports using 48VH successfully: viewtopic.php?f=6&t=6288
In this thread, someone reports using 48V successfully: https://community.ui.com/questions/Rock ... 6a6be54e2b

From the last thread

As for power, 18VDC-54VDC is supported. I believe there are a few LTU users deploying these with Netonix switches. Which every you use, make sure to use the 4 pair power options.

I ran one at 48V successfully for a short time while trialing LTU equipment, although my test used < 5m of cable.

I don't think I have seen posts from anyone claiming that switching from 48V to 48VH resolved any issues for them, but I have seen posts stating that 24V to 24VH and 24V to 48V solved issues.

In short, no option on Netonix devices produced to date should damage an LTU rocket, 48V will probably solve your issue if it is power related, you can use 48VH as recommended, but it is probably unnecessary and restricts the ports you can use.

[mike99]

The answer is in the datasheet
Pins 1, 2; 4, 5+ and Pins 3, 6; 7, 8-
+18 to +54 VDC
https://dl.ubnt.com/ds/ltu-rocket

Also note the max power is 25W

If you look at netonix power spec, VH use
Pins 1,2,4,5 (+), Pins 3,6,7,8 (-)
https://netonix.com/wisp-switch/ws-12-400-ac.html

So, VH use same pinout and 24V and 48V are both in the voltage range.

Any between 24V, 24VH, 48V and 48VH shouldn't damage the radio.

24V = 18W, 24VH = 36W, 48V = 48W and 48VH = 72W. Since the radio spec sheet indicate max 25W, the 18W provided by 24V is not enough.

I would personally use 48W and spare VH port for radios that really need it.

[monty1157]

Thanks all. I took the safer (In my mind anyway. There's been the odd occasion in the past during the period Ubiquiti kit swapped from 48v units to 24v where power bricks got mixed up) option to run at 24VH due to the lack of easy access to the radio and the fact that I didn't have a spare LTU to test on the ground at 48V/VH.
I also don't know why I missed the voltages in the datasheet. I suppose that's what happens when you're relegated to doing all this stuff from an office and not out on site like before.

Once again, thanks for the help and clarification.

Cheers,
Mark