Motorola could have done us all a favor by just superimposing a 1 or 2 volt drop on the power than totally interrupting it. Just put a 1 Hz square wave at the top of the power. The total interruption and terribly narrow pulse width has cause lots of issues over the years.
From: Forrest Christian (List Account) Sent: Tuesday, November 10, 2015 2:11 PM To: af Subject: Re: [AFMUG] SyncInjectors and PMP450i It's a bit more complicated than that.. Yes, the pulse is effectively fed through the syncinjector. The injector doesn't (as an example) realign the pulse, or anything like that. It does, however, control the length of the power interruption and is able to simply ignore a pulse if it deems it too close to a previous pulse. If it ignores one, it increments the 'ignored pulse' counter. That prevents a string of pulses (potentially caused by an outside source) from creating a situation where the radio isn't getting enough power due to there being more pulses than needed. Generally, if a pulse occurs sooner than 0.5S after a previous one it will ignore the pulse (pulses normally occur once every second - no more, no less). On Tue, Nov 10, 2015 at 12:57 AM, George Skorup <[email protected]> wrote: Is the pulse from the pipe effectively fed directly into the radio ports and the SyncInjector just monitors it? Or does the SyncInjector reference the pipe's output and regenerates before output to the radios? I know the radios don't really care about a lost pulse here and there. IIRC, it's like 5 seconds before they declare it lost. If it's not this then I'm completely lost. Just odd that this seems to be happening on the towers with the longest runs (240-290 feet). But I'm far from blaming the SyncInjectors and/or SyncPipes. I really do believe this is some Canopy bug. I have the on-board GPS disabled on most of them that are exhibiting this issue. The last time, I went in and turned them back on and the on-board pulse was flip-flopping every second or two just like the power port. Cambium can't reproduce it yet as far as I know. And this really seemed to start happening when we got AutoSync. I've even seen this happen on single sectors with their own parasitic pipe as well (no power port timing, and with the on-board enabled and disabled). So I'm not sure if the on-board is causing this, but you'd think if it was disabled, then it should not be possible, but disabling it doesn't actually turn the receiver off. And like I said, it seems to happen around sundown which tells me it's either a temperature thing or a GPS Rx issue, plus all of the on-board receivers are aimed at the horizon through tower steel. And I have other receivers on the same sites to time FSK radios and they don't have any problems, just timing ports from deluxe's and parasitics, no other SyncInjectors though. I set up a cron script on an NTPd sync'd server to poll the 'used pulses' counter every hour and output it to a file. We'll see what that says. On 11/10/2015 12:38 AM, Forrest Christian (List Account) wrote: This problem isn't likely to affect all of the radios randomly at the same time. Since each port is driven by a separate set of electronics, and you have a separate cable to each radio, any effect should be radio-specific. I just looked at the syncinjector firmware - it needs 3-4 lost pulses before it declares the sync to be lost. I'm planning on tightening this up a bit to better catch errors like these, but I've got a couple of other critical items I'm working on before I can get there. Have you by chance looked at the increments of the sync pulses through a 24 hour period? In exactly 24 hours, there should be exactly 86,400 sync pulses used - no more no less. If you compare this to a atomic-synced clock you should be able to get fairly accurate counts. I.e. read that counter exactly at the top of an hour, and then look exactly 24 hours later. Be aware of non-accurate clocks though - my computer drifts a few seconds a day, if I don't sync it regularly (like a couple of times an hour). -forrest On Mon, Nov 9, 2015 at 4:58 PM, George Skorup <[email protected]> wrote: OK, now I'm very interested. I have multiple sites with regular 10/100 SyncInjectors with 450 APs on them (no need for GigE). They're all on 200 feet or more cable. Randomly, all APs at a site will show loss of power port sync. More often, they say the sync pulse is flip flopping on and off. Sometimes a reboot or a power-cycle will fix it, but mostly just have to wait a few minutes for it to clear. This seems to happen right around sundown most times. I was thinking that the on-board GPS starts freaking out and triggers some AutoSync bug (which I know exists). I've pulled out all surge suppressors, swapped SyncInjectors, SyncPIpes, nothing. And when this happens, the SyncInjector status says the timing is fine, no events, every time. But maybe this is actually my problem?? It has been very very rare on shorter runs (like <150 feet). On 11/9/2015 5:20 PM, Forrest Christian (List Account) wrote: Sort of. First of all, a normal pulse out of a syncinjector into a short cable: Interesting things happen when you shoot this into a long cable: Those bounces at the front are my best guess as to what is causing the 450i to not like the sync pulse. That's on a 100m cable, and those pulses are most likely caused by the signal bouncing off the end of the cable and back and/or some different interaction with a long CAT5 cable. It should be noted that similar bounces also happen with the 100 and the 450, and even with official cambium sync sources (aka the CMM Micro), but the software in those radios seem to ignore the stray pulses, only paying attention to the final edge. Not so with the 450i. It just refuses to play. The new I0 injectors turn the power off a bit more smoothly, making the bounce not exist, even on a long cable: On Mon, Nov 9, 2015 at 4:02 PM, George Skorup <[email protected]> wrote: Let me guess, they only take a CMM4 aligned pulse? On 11/9/2015 4:21 PM, Forrest Christian (List Account) wrote: We have recently become aware of a potential issue when using a SyncInjector with a PMP450i. The short version of this issue is that with certain cable runs (mostly longer ones), a PMP450i will refuse to accept the sync from the SyncInjector as valid, even though the pulse is perfectly valid and should be accepted by the PMP450i. Currently, there are two ways this can be fixed. Since the pulse is valid, but just not recognized as valid by the currently shipping PMP450i firmware, Cambium could fix this in software. I believe they are currently investigating this as an issue, and I honestly expect them to release a fix assuming it isn't a major issue to do so. If this happens, it should address all of the existing SyncInjectors in the field which our customers may want to use in the future with a a PMP450i. The second way to fix this issue is for us to modify our sync pulse slightly so that it is in line with what the PMP450i is expecting. Because this modification has some additional benefits beyond better interoperability with the current PMP450i firmware (such as the modified pulse being less likely to induct noise into adjoining cables), we have decided to proceed down this path as well. During the next week or so, we will begin shipping Revision I0 of our Gigabit SyncInjector Product. The first of these are currently working their way through our assembly line. This version contains improved support for voltages above 58V and also the waveform modification mentioned above. It should be functionally identical to the earlier Revision H0 SyncInjectors. It is not our intention to update our non-gigabit injectors at this time. If you are currently having problems with sync over power on a Gigabit SyncInjector and a PMP450i, please send an email into [email protected] and we will work with you to ensure you have hardware which will work with your hardware. -- Forrest Christian CEO, PacketFlux Technologies, Inc. Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] | http://www.packetflux.com
