820C/S most definitely tie DC plug + to chassis. Believe me. I smoked a RackInjector PDU board not paying attention. POE into those is floating. They'll basically take any 4pr scheme you throw at it. I have a couple 820S's running on AirFiber POE bricks.
Yes, I still do red for +24, orange for +48 and blue for -48 at mixed sites. Just makes sense to me. A wise man will use a labeler too. Which I *always* do. [sarcasm emoji] On Mon, Sep 21, 2020 at 2:25 PM Mathew Howard <mhoward...@gmail.com> wrote: > hmm... that's an interesting point about the direct DC input... I suppose > it would be possible to have POE floating and the direct DC input tied to > ground. Without thinking about it too much, it seems to me that would > probably require some somewhat complicated circuitry that most likely isn't > there though... > > On Mon, Sep 21, 2020 at 11:01 AM Ken Hohhof <af...@kwisp.com> wrote: > >> I can’t comment specifically on DC direct power to an Aviat radio. Most >> 802.3 POE powered radios are in fact floating and don’t care, but I’m not >> sure about the direct DC input. >> >> >> >> As far as does one radio dictate how you power everything else? No, but >> it does complicate things. I have a site that was built with Eltek -48 VDC >> because we had a Purewave WiMax basestation which required -48V DC direct >> power. We had several things like Mikrotik, Packetflux, Cambium and >> Ubiquiti that needed +24, so we have a Traco DC-DC converted that generates >> +24 from the -48 Actually it just generates 24 volts floating and we >> connect the – side to ground. Then we got rid of the Purewave and replaced >> it with Cambiumj 450i which needs +48 (or +56), so we added a Mean Well >> DC-DC converter to give us +48. So now we have -48, +24 and +48 in the >> same enclosure, each with their own bank of dual level DIN rail fuses for >> distribution. The DC-DC converters are relatively small DIN rail supplies, >> so all of this takes us less room than it sounds like. >> >> >> >> Actually we now feed this site with an 11 GHz PTP820S, and we used one of >> the DC powered POE injectors that can take + or – 24 or 48 volts, connected >> to the Eltek -48V. Could have also used a Cat6-POE-APC off the +48V rail. >> At some point we will probably switch to a +48V battery system since we >> don’t specifically need -48 anymore. But this should demonstrate that you >> can have all sorts of DC voltages at a site, some with the + side connected >> to ground, some with the – side connected to ground. You just need to keep >> your documentation straight. The most complicated thing is probably >> choosing wire colors. I use a lot of red/black zip cord so I’ve just >> accepted that red is + and black is – and you can’t make assumptions about >> which side is grounded. You could make a different decision and red is >> always hot and black is always ground. Or don’t use zip cord and buy lots >> of colors of wire. For awhile I was doing stuff like blue was -48 and red >> was +24 and yellow was +48 and orange was from the charger to the batteries >> and it got really confusing. >> >> >> >> >> >> *From:* AF <af-boun...@af.afmug.com> *On Behalf Of *Josh Baird >> *Sent:* Monday, September 21, 2020 10:07 AM >> *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> >> *Subject:* Re: [AFMUG] -48 noob questions (mikrotik) >> >> >> >> I run WTM4200's off of +48VDC plants. Reach out to Ken Ruppel if you >> want/need more details. >> >> >> >> On Mon, Sep 21, 2020 at 11:05 AM Steve Jones <thatoneguyst...@gmail.com> >> wrote: >> >> These are wtm4200. He told me the connector in the radio bonds + to >> ground at the radio. Could be wrong. I'm outside my wheelhouse anyway with >> this being our first direct dc radios. >> >> >> >> On Mon, Sep 21, 2020, 10:00 AM Josh Baird <joshba...@gmail.com> wrote: >> >> I should have said -- at least the WTM4200 and WTM4800, both of which I >> have used. >> >> >> >> On Mon, Sep 21, 2020 at 10:59 AM Josh Baird <joshba...@gmail.com> wrote: >> >> Aviat radios don't bond + or - to the chassis. You can run them at >> -48VDC or +48VDC. >> >> >> >> On Mon, Sep 21, 2020 at 10:45 AM Steve Jones <thatoneguyst...@gmail.com> >> wrote: >> >> 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 >> >> -- >> 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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