Nice, thank you for doing the test and posting the results! I think this sort of confirms what we were all thinking.
On Fri, Jan 22, 2016 at 3:22 PM, Andy Trimmell <atrimm...@precisionds.com> wrote: > So I did some testing today by freezing the AP in the freezer. Heater warm > up varied between 1 minute and 3 minutes. The amps per unit during the heat > up time is .45 amps per AP. We were finding that even if its warmed up and > you unplug it 10 seconds later it will warm up again and again. After the > warm up the AP drops its amps to .2 amps. We are using 2.1amp psu to feed > several APs because we never use more than that but I think when these > heaters get turned on during the bootup process we exceed it and overload > the psu. > > > > This was all ran into Packetflux gear with a SOLA power supply 2.1Amp. > We’re going to split the load so if there’s a power blip where the backup > doesn’t catch it in time all 3 aren’t starting up heaters at the same time. > > > > Hope this information helps. > > > > -Andy > > > > *From:* Af [mailto:af-boun...@afmug.com] *On Behalf Of *ch...@wbmfg.com > *Sent:* Thursday, January 21, 2016 12:03 PM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] To Cambium With Love - Replace the bad ePMP units. > > > > Or automotive grade. > > > > *From:* Ken Hohhof <af...@kwisp.com> > > *Sent:* Thursday, January 21, 2016 9:15 AM > > *To:* af@afmug.com > > *Subject:* Re: [AFMUG] To Cambium With Love - Replace the bad ePMP units. > > > > Or here’s a thought: pay the money for industrial temperature range parts! > > > > *From:* Adam Moffett <dmmoff...@gmail.com> > > *Sent:* Thursday, January 21, 2016 10:08 AM > > *To:* af@afmug.com > > *Subject:* Re: [AFMUG] To Cambium With Love - Replace the bad ePMP units. > > > > They have said there's a resistive heater. I heard it in ePMP training in > Albany and I've seen it stated on this list. > > If I remember correctly (I might not), they wanted the CPU to hit a > certain temp before starting up. If it was too cold you'd see a delay in > startup of up to 2 minutes while waiting for this heater to bring the CPU > up to temp. I've never actually observed the delay, so I guess they're > talking about Alaska cold, not NY cold. > > On 1/21/2016 10:47 AM, Forrest Christian (List Account) wrote: > > I looked at the high resolution photos on the FCC site and didn't see > anything obvious. Now I've got the one I have on the bench out of the > case, I still don't see anything obvious heater-wise, but again I'm not > going to pop the shields off the board (requiring desoldering), to be 100% > sure... > > > > On Thu, Jan 21, 2016 at 8:30 AM, Steve D <bigd...@gmail.com> wrote: > > Just throwing this out there, but don't the epmp's have a small heater in > them that could be turning on when it's cold, drawing additional power? I > recall it was supposed to pre-heat components to avoid freezeup on first > boot but I can't recall if that's the only time they run or not. > > > > -Steve D > > > > On Thu, Jan 21, 2016 at 1:44 AM, Forrest Christian (List Account) < > li...@packetflux.com> wrote: > > I do want to clarify one item: > > This is not necessarily related to the cambium DRAM issue. I don't want > to claim that problem, since this isn't the same thing. This is more of > an issue where you have ePMP's which seem to start having power-related > issues. If moving to a 30V brick makes your problem go away, then the > issue I describe below probably is your issue. If moving to a higher > voltage doesn't fix the issue then this probably doesn't relate to your > issue. Regardless, it is my intent to recommend that my customers move to > 48V as soon as I confirm that this seems to fix at least a decent number of > the problems without causing others. > > Unfortunately this might be a case of the cold weather aggravating two > separate issues (or for that matter, the cold weather causing increased > current consumption in the ePMP, which then requires a higher voltage to > operate correctly). > > -forrest > > > > On Thu, Jan 21, 2016 at 12:43 AM, Forrest Christian (List Account) < > li...@packetflux.com> wrote: > > A bit of an update from the PacketFlux side. > > Late this afternoon I received a ticket from Tyson in relation to these > issues. In particular, sync from a PacketFlux SyncInjector dropping off on > an ePMP when it's cold. I have spent a bit of time this evening > investigating this issue. The following is a summary of what I found. > It's a bit long-winded so that those experiencing the problems can > understand my current working theory and help me figure out if this is the > case. > > WARNING: The following is based on a limited amount of testing with a > single ePMP with no traffic and no clients and on a bench. This is likely > the best case scenario. The field is only going to be worse. > > The setup is as follows: > > ePMP 1000 GPS AP, with no GPS hockey puck attached, connected to a Gigabit > Syncinjector (Rev H and Rev I - I have a special one with a port of each > 'type' ;-) ). I am powering the injector with a variable power supply so > I can vary the voltages in. The AP is connected to the Injector with ~100m > of CAT5 cable. The Antenna connectors have terminators on them, the AP is > in transmit mode, but isn't passing any traffic since there are no clients. > > When feeding the injector with 24V, I get about 23V at the AP. This is > pretty consistent with what I would expect in this situation. The AP > seems to work fine, at least on the bench and without doing any real > work. However, as the voltage drops, things start to get weird: > > At around 22V in, (21V at the AP), Sync becomes flaky. This is consistent > on both H and I version ports on the injector. Sometimes it works, > sometimes it doesn't. Note that 22V is the bottom of the rated voltage > inputs for the ePMP. > > At around 20.5V in (19.5V at the AP), the radio just turns off. It won't > turn back on until around 22V. > > Now here's where some total speculation comes to play. On the bench, > this unit is drawing around 3W. Let's assume that under load, and when > temperatures are cold, this unit draws closer to 6W. This would double the > current, and quadruple the voltage drop. Now, assume 24V in, this puts you > at around 20V in at the AP, which is about the turnoff point. Remember > this is on 100m of wire, and a total speculation about a the power draw of > a cold, under load AP. But the point is valid, regardless of the cause - > if the circuit resistance when combined with the power load causes a low > enough voltage at the AP, weird things will happen. And since weird things > seem to start to happen around 22V, there just isn't much headroom at > 24V. > > This explains why things work well at 30V. > > For those who are having this problem I'd recommend trying increasing the > voltage into the SyncInjector. The Revision H injectors can safely handle > up to around 56V or so. Assuming all of the radios on an injector are > either ePMP or the newer 450i's, using 56V into a SyncInjector is perfectly > acceptable and the ePMP's are rated up to 56V as well. > > So the summary: Try a 48VDC voltage source instead of 24V and see what > happens. > > -forrest > > > > > > > > > > > > > > > > > > On Wed, Jan 20, 2016 at 11:00 AM, Tyson Burris @ Internet Communications > Inc <t...@franklinisp.net> wrote: > > Hello Cambium, > > > > At the MidWest-IX launch party last night, several of us Indiana WISPs > compared notes on the ‘cold weather’ problems we are seeing with ePMPs. It > was very interesting to learn we are experience identical problems across > the spectrum. > > We all understand this is a DRAM issue with certain units you have > identified. We also understand the firmware RC that has been made > available to fix this short term. > > The bottom line is we are very frustrated and grow tired of dealing with > it. > > > > Our concern is simple. If your software fix ‘degrades’ the performance of > the product or triggers other issues, as it has been suggested, we would > prefer a full recall and replacement program immediately. > > > > If the suggestion that the fix will degrade the product performance is > inaccurate and not cause other issues, I would like for this to be made > public. > > > > Thank you, > > > > *Tyson Burris, President* > *Internet Communications Inc.* > *739 Commerce Dr.* > *Franklin, IN 46131* > > *317-738-0320 <317-738-0320> Daytime #* > *317-412-1540 <317-412-1540> Cell/Direct #* > *Online: **www.surfici.net <http://www.surfici.net>* > > > > [image: ICI] > > *What can ICI do for you?* > > > *Broadband Wireless - PtP/PtMP Solutions - WiMax - Mesh Wifi/Hotzones - IP > Security - Fiber - Tower - Infrastructure.* > > *CONFIDENTIALITY NOTICE: This e-mail is intended for the* > *addressee shown. It contains information that is* > *confidential and protected from disclosure. Any review,* > *dissemination or use of this transmission or its contents by* > *unauthorized organizations or individuals is strictly* > *prohibited.* > > > > > > > -- > > *Forrest Christian* *CEO, PacketFlux Technologies, Inc.* > > Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 > > forre...@imach.com | http://www.packetflux.com > > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > > > > -- <http://www.linkedin.com/in/fwchristian> > > *Forrest Christian CEO, PacketFlux Technologies, Inc. > <http://www.linkedin.com/in/fwchristian>* > > Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 > <http://www.linkedin.com/in/fwchristian> > > *forre...@imach.com* | *http://www.packetflux.com* > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > > > > -- <http://www.linkedin.com/in/fwchristian> > > *Forrest Christian CEO, PacketFlux Technologies, Inc. > <http://www.linkedin.com/in/fwchristian>* > > Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 > <http://www.linkedin.com/in/fwchristian> > > *forre...@imach.com* | *http://www.packetflux.com* > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > > <http://www.linkedin.com/in/fwchristian> > >
