It only does things to voltages that exceed the surge suppression limits. It is only clamping long surges (>1uS), but it is absorbing really fast spikey surges related to POE rather than allow all the diodes to conduct. It is not modifying the waveform at all but rather dividing up the surges depending on speed and amplitude.
From: Ken Hohhof Sent: Monday, October 03, 2016 4:06 PM To: [email protected] Subject: Re: [AFMUG] 450i Problems maintaining gigabit. Even if intended to make things better, I feel queasy about the idea of a surge protector purposely modifying the waveform. Especially as a “running change” to an existing product. It seems like the aim of a surge protector should be to affect the signal as little as possible while clamping surges. At a minimum, I would ask that you mark the new version somehow so that we know what we’ve got. From: Af [mailto:[email protected]] On Behalf Of Chuck McCown Sent: Monday, October 3, 2016 4:07 PM To: [email protected] Subject: Re: [AFMUG] 450i Problems maintaining gigabit. I have tried to avoid publically singling out a manufacturer, but a certain manufacturer we all love does have something goofy with the sync over power. It has some nasty risetime glitches and overshoots that cause many surge suppressors to conduct -thus causing data glitches and the drop from Gig to 100 Mbps. It is proportional to cable lengths I believe but I have not proven that. It is also something relatively new. Perhaps because Gig interfaces on their radios are relatively new. So, I just made the surge suppressor eat the overshoot. Belt, suspenders, now flack jacket. Triple protection. It really made the whole design that much better. I have added the spike eater to all products going forward. There are not many in the pipeline yet, and you really don’t need it unless you want to use that particular sync over power product... From: George Skorup Sent: Monday, October 03, 2016 2:00 PM To: [email protected] Subject: Re: [AFMUG] 450i Problems maintaining gigabit. It happens on the regular 450 AP too. 1000Base-T does not work at all with GigE-APC-HV's in line. It is 100% the sync pulse causing the SS to clamp. I won't speak for Chuck, but he sent me some stuff to test and it works. This was a yet unused 5GHz 450 AP at a site with ~220 feet of Shireen DC-1021. No SS on top. GigE PowerInjector+Sync fed with regulated 24v. I have GigE-APCs on tons of POE and non-POE gigabit links *without a sync pulse* and they work perfectly fine. It would not surprise me if other brands of suppressors are doing the same thing because of the sync pulse. Maybe it takes the right conditions like temperature, power draw, etc. It's just immediately obvious with the GigE-APCs because they are moar betterer. On 10/3/2016 12:45 PM, Forrest Christian (List Account) wrote: We have very recently started getting a whole bunch of support queries which are from customers maintaining a gigabit link on a 450i. The link seems to come up at gig, then some time later drops back to 100Mb/s. So far, we haven't nailed down a cause. Some seem to be related to the sync pulse, others are completely unaffected by this. Some seem to be related to the addition of a surge suppressor to the link (even a good quality one), some not. I'm even aware of quite a few cases where replacement of our gear with a stock cambium injector doesn't fix the problem - so I'm pretty comfortable in feeling that something other than our power injection equipment is the root cause. The commonality of most of these are longer cable runs. All of the normal things have been tried (swapping cables, reterminating ends, validating cables, etc.). I also suspect that these are newer 450i's. (I'm not sure if we've seen this on a 450 or not). So, what I'm hoping for from the list is to determine if this problem is widespread, and if there seems to be any relation to how old the 450i is, or a firmware version update, or something else so I can help fix this for my customers. Any information would be helpful. -- Forrest Christian CEO, PacketFlux Technologies, Inc. Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] | http://www.packetflux.com
