So, like on these aviats, my contractor says they're -48v, but the connector in the radio bonds to ground. Does that mean my whole site has to have -48v or just radios powered by that particular psu?
On Mon, Sep 21, 2020, 8:59 AM Ken Hohhof <af...@kwisp.com> wrote: > Now if we could get the manufacturers to be less secretive about their POE > schemes. They mostly want you to use their POE device and don’t want to > document the pinouts or explain if it matters which side is referenced to > ground. > > > > Mostly I find that using a Cat6-POE-APC with the jumpers as set at the > factory and + and – hooked up per the markings works. Which is basically > 802.3at. It works with the – side grounded, I suspect it would also work > with the + side grounded, or neither. I was hesitant to use this on a > PTP820 but it works fine. I don’t know why they make their POE scheme > sound so mysterious. > > > > > > *From:* AF <af-boun...@af.afmug.com> *On Behalf Of *Josh Baird > *Sent:* Monday, September 21, 2020 8:44 AM > *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> > *Subject:* Re: [AFMUG] -48 noob questions (mikrotik) > > > > Yep - great explanation! > > > > On Sun, Sep 20, 2020 at 4:55 PM Chuck McCown <ch...@wbmfg.com> wrote: > > You have a power supply, say a 6 volt car battery. You connect a pair of > headlights to it with two wires. All is well. > > > > Now you start building cars. And you are going to wire up the > headlights. Someone points out that you can save some money on wiring by > using the car chassis instead if one of the wires. > > > > You decide to run the positive connection from the battery to the > headlights with wire and return the current via the car’s chassis. > > > > Now you have turned a 6 volt electrical system into a +6 volt system. If > you reverse the battery and connect the + side to the chassis and run the > wire from the negative post to the headlights , it will still work fine. > The headlights don’t care. Now you have a -6 volt electrical system. > > > > The headlights don’t care but the radio does. Most radios expect the > chassis to be negative and their power wire to be positive. You can > “float” the radio by mounting it on an insulator and connecting its power > wire to the car’s chases and the chassis of the radio to the negative wire > going to the battery. A bit dangerous but I have had to do this at times. > > > > Oh, and the car is an early VW. > > Sent from my iPhone > > > > On Sep 20, 2020, at 2:19 PM, Steve Jones <thatoneguyst...@gmail.com> > wrote: > > > > I still cant comprehend any of this. I'm just dumb when it comes to it > > > > On Sat, Sep 19, 2020, 2:51 PM <ch...@wbmfg.com> wrote: > > Yes. > > > > *From:* TJ Trout > > *Sent:* Saturday, September 19, 2020 1:48 PM > > *To:* AnimalFarm Microwave Users Group > > *Subject:* Re: [AFMUG] -48 noob questions (mikrotik) > > > > It's just a simple 48 to 12v converter to feed the mikrotik. I tested with > a ict +48 supply and the 12v comes out fine, I'm 99% sure it will work on > the wood bench, and about 90% sure it will work in a rack. > > > > If it was true -48 I would assume the + terminal would be bonded with > chassis ground? > > > > On Sat, Sep 19, 2020, 12:45 PM TJ Trout <t...@voltbb.com> wrote: > > I think some of my devices have the chassis ground bonded with the > negative input terminals, I discovered this > because I am running a telecom rectifier shelf designed for -48 on a +48 > system because it's floating, but this > causes the + output to not be fused, so I practiced arc welding once. > > Strange, didn't know the 1100 had dc input, but it looks floating though > (per specs -48, 12-57 V) > > > > > On Sat, Sep 19, 2020 at 12:40 PM <ch...@wbmfg.com> wrote: > > I don’t think I have ever seen a true +48 load. > > > > *From:* Ken Hohhof > > *Sent:* Saturday, September 19, 2020 1:29 PM > > *To:* 'AnimalFarm Microwave Users Group' > > *Subject:* Re: [AFMUG] -48 noob questions (mikrotik) > > > > Different situation, but I have several sites with 1100ahx4 powered with > +48, even though Mikrotik says they take -48. I suspect you will find the > same to be true on the CCR. > > > > Connect the – terminal to ground and the + terminal to +48, obviously you > don’t want to apply reverse polarity by trying to connect +48 to the -48 > terminal. > > > > I have some ccr1009 and ccr1036 but they are all AC powered, and I have no > ccr1072, so I can’t answer your exact question. > > > > > > *From:* AF <af-boun...@af.afmug.com> *On Behalf Of *TJ Trout > *Sent:* Saturday, September 19, 2020 2:19 PM > *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> > *Subject:* [AFMUG] -48 noob questions (mikrotik) > > > > So I have a handful of ccr1072's that I want to run on our +48v plant, > mikrotik sells a '-48v telecom' power supply and they insist it's not > compatible with +48v. I ordered one for testing and both +/- input > terminals have no reference to chassis ground. I went ahead and applied > +48v and the power supply fired up (no smoke) and when measuring from > chassis ground to the input terminals I see no difference in potential. > > > > Before I shove this into a $3,000 router I wanted to see what I may be > missing here? > ------------------------------ > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > ------------------------------ > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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