Everything depends on what polarity is connected to the case/chassis of the
radios.
If neither power polarity is bonded to the case, the radio is floating and
you can connect it to any source.
But if one radio has positive bonded to the case and the other has negative
bonded to the case, if you connect them to the same power supply (assuming
it is floating too) they will be fine until you bolt them to a tower whereby
the tower will short everything out.
Also, note that some power supplies bond one polarity to ground as well.
So, more data is needed.
-----Original Message-----
From: Craig Baird
Sent: Tuesday, January 05, 2016 11:47 AM
To: [email protected]
Subject: [AFMUG] -48v radio on same tower with +48v radio
I have a terrible time wrapping my head around -48vdc. I'm hoping you
guys can help. I've got a Cambium PTP820S that I'm going to be
putting on the same tower with several Mimosa B5s. The 820S is
apparently -48vdc, while it appears the Mimosa is +48vdc. I'd like to
power both with a Meanwell AD-155C with a 48v battery string. So...
what are my implications here? Will having both -48 and +48 radios on
the same tower, coming from the same power supply end up shorting
through the tower? What's the best way to do this short of using two
separate power supplies and battery strings?
Thanks!
Craig
