Re: [AFMUG] Cambium 820C -48v power supply questions

Bill Prince Sun, 31 Mar 2019 08:58:49 -0700

It would be simple enough to determine if the device has a floating ground or not. Simply start with a power supply that has a floating output and connect it to the power input. Then measure the potential between ground and each leg.

I have done this in the past with a few different Dragonwave radios. In all the cases I looked at, they were floating. This, in spite of the fact that they were listed as -48V devices.

bp
<part15sbs{at}gmail{dot}com>

On 3/31/2019 8:51 AM, Ken Hohhof wrote:

Yes it is basically a rebranded Ceragon IP20 but still, that’s pretty sad, if Cambium support can’t answer a question about how to power it. It’s hard to believe nobody at Cambium knows the answer, and if they really don’t, they could call Israel and ask.

From: AF <[email protected]> On Behalf Of Jeremy
Sent: Sunday, March 31, 2019 10:37 AM
To: AnimalFarm Microwave Users Group <[email protected]>
Subject: Re: [AFMUG] Cambium 820C -48v power supply questions

I am using the DC power connector, not POE. I spoke with Cambium and they did not seem to have the answer as to whether or not this would work, and the details of their -48v being floating or not.

On Sat, Mar 30, 2019 at 4:55 PM Ken Hohhof <[email protected]> wrote:

It sounds like he wants to use the DC power connector.

Cambium doesn’t do a very good job of answering the question in any of their documentation. Several places they refer to the direct DC power as -48 which I would take to mean positive side grounded.

One tends to assume that when powering via POE, the radio takes the DC from the Ethernet transformers and uses it just like it would direct DC power, but I’m kind of getting the impression that’s not true.

PTP820C/S can definitely accept floating power via POE, and I could swear I have several sites using +48 VDC power (negative side grounded) for POE via a GIGE-POE-APC.

Keep in mind that no matter which side of the power supply is grounded, + goes to + and - goes to -. That seems to confuse some people.

You might want to open a support case on the Cambium website and get them to answer the question.

From: AF <[email protected]> On Behalf Of Gino A. Villarini
Sent: Saturday, March 30, 2019 2:59 PM
To: AnimalFarm Microwave Users Group <[email protected]>
Subject: Re: [AFMUG] Cambium 820C -48v power supply questions

Are you using Trango POE? IIRC it’s a proprietary pinout..

Gino Villarini
Founder/President
@gvillarini
t: 787.273.4143 Ext. 204
m:

www.aeronetpr.com | Metro Office Park #18 Suite 304 Guaynabo, PR 00968

From: AF <[email protected]> on behalf of Jeremy <[email protected]>
Reply-To: AnimalFarm Microwave Users Group <[email protected]>
Date: Saturday, March 30, 2019 at 12:12 PM
To: AnimalFarm Microwave Users Group <[email protected]>
Subject: [AFMUG] Cambium 820C -48v power supply questions

I am confused. I have a 6A rackmount Trango Power supply http://www.silverbranch.com/Useppa/DS-9030-C-Giga-PowerSupply-1U-48.pdf that I would like to use to power an 820C. I hooked it up -48v and it would not power on. I hooked it up +48v and it worked perfectly. This is on the bench and not installed. I am hearing from others on here that the power supply will short as soon as I ground the radio if I actually run it at +48v. So I have a few questions....why won't this power up at -48v? I really don't want to use POE. What are people using to power these? Any reason that this Trango Power supply should be not working?

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Re: [AFMUG] Cambium 820C -48v power supply questions

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