PoE RadioTest Safe Practices

[gripper]

After reviewing the LIST OF POE DEVICES THAT DO AND DO NOT WORK WITH WISP SWITCHES discussion again, I'm still a little unsure about compatibility of a few radios I'd like to power (Radwin, Ceragon, Wavion). I'm thinking about a safe method to test quickly (radios are in service, site gets reworked in a short maintenance window when we'd all like to be snoozing). Here's what I have:

1. Test voltage and polarity coming off standard PoE injector with a multimeter. Check radio power consumption from specs.

2. If polarity is reversed (4,5 -, 7,8 +) re-terminate radio feed cable swapping 4<->8 and 5<->7 (or should it be 4<->7 and 5<->8 ? Does it matter? Can this work in any case for 1000X which uses all 8 pins for data, or are we just S.O.L for reverse pol Gigabit?)

3. Power up radio from switch at 24v or 48v if power consumption spec is <20w (24v) or 40w (48v). If power consumption spec is greater than those limits, and polarity is NOT reversed, power up at 24VH (DC switches) or 48VH as appropriate.

4. If radio appears to power up but isn't happy, and polarity is NOT reversed, plug in a crossover adapter (but not with 48VH!) If that works rework cable swapping 1,2 and 3,6.

5. What about units that show reverse polarity and require high power? ( I think the Ceragon IP-20C=Cambium 820 might fall into this class).

What do I have wrong?

[sirhc]

1. Test voltage and polarity coming off standard PoE injector with a multimeter. Check radio power consumption from specs.

GOOD

2. If polarity is reversed (4,5 -, 7,8 +) re-terminate radio feed cable swapping 48 and 57 (or should it be 47 and 58 ? Does it matter? Can this work in any case for 1000X which uses all 8 pins for data, or are we just S.O.L for reverse pol Gigabit?)

No this will only work with 10/100 devices as only Pairs 1 and 2 are for data and Pairs 3 and 4 are un-used and this they are only for power so they can be swapped.

3. Power up radio from switch at 24v or 48v if power consumption spec is <20w (24v) or 40w (48v). If power consumption spec is greater than those limits, and polarity is NOT reversed, power up at 24VH (DC switches) or 48VH as appropriate.

Selecting 24VH and 48VH is only advisable IF the radio is designed to accept power on all 4 pairs otherwise BAD THINGS CAN/WILL OCCUR.

Actually 24V and 48V supports .75 amps so...
if using 24V that would be .75A x 24V = 18 watts
if using 48V that would be .75A x 50V = 37.5 watts - *Note our 48V is really 50V*

4. If radio appears to power up but isn't happy, and polarity is NOT reversed, plug in a crossover adapter (but not with 48VH!) If that works rework cable swapping 1,2 and 3,6.

You normally never swap pairs 1 and 2 unless you want to reverse polarity on those pairs if using a VH POE option and the devices needs a cross over cable....NOT VERY LIKELY AS MOST DEVICES ARE AUTO MDX SINCE ABOUT 1998

5. What about units that show reverse polarity and require high power? ( I think the Ceragon IP-20C=Cambium 820 might fall into this class).

You probably will not be able to power these devices as they would require a special piece of equipment to achieve this and no one makes one.

[gripper]

No this will only work with 10/100 devices as only Pairs 1 and 2 are for data and Pairs 3 and 4 are un-used and this they are only for power so they can be swapped.

So, unlikely we get a reverse polarity 1000X radio to play nice unless it has a polarity detection/reversing ability--I think you referenced some mfr. that does this...

Selecting 24VH and 48VH is only advisable IF the radio is designed to accept power on all 4 pairs otherwise BAD THINGS CAN/WILL OCCUR.

Any way to determine this if documentation is not available? (power on all 4 pairs is not a standards compliant approach, is it?)

You normally never swap pairs 1 and 2 unless you want to reverse polarity on those pairs if using a VH POE option and the devices needs a cross over cable....NOT VERY LIKELY AS MOST DEVICES ARE AUTO MDX SINCE ABOUT 1998

There's a post in the "LIST OF POE DEVICES..." discussion that claims that Wavion N radios require a crossover and work...
It seems to me this could work only if NOT using a VH option, or am I missing something? Or are you saying that reversing pairs 3 and 4 for reverse polarity and reversing 1 and 2 for crossover would likely give you correct power polarization for radios that want power on all four pairs?

gripper wrote:5. What about units that show reverse polarity and require high power? ( I think the Ceragon IP-20C=Cambium 820 might fall into this class).

You probably will not be able to power these devices as they would require a special piece of equipment to achieve this and no one makes one.

Again, I'm seeing claims (on the same discussion, and getting PM confirmation) that the IP-20C is working fine with standard 48VH despite seemingly clear documentation that this is -48VDC...we're powering these now with separate 48VDC + ground power supplies feeding their "proprietary" PoE injectors. This is their spec for power to the injectors, though the spec for the power to the radio itself seems more liberal. How can this be working on standard 48VH?