Just FYI, the stuff Chuck sent me was tested at an FM site. I believe
they're putting ~2500 watts into a 2" transmission line with 2 or 3 bays
at 350 feet. Might be 4 bays, I don't remember. We're at 200 feet with
our 450 cluster. I don't get any errors with the GigE-APCs in-line
(100Mbps w/ sync, or gigabit w/o sync), nor with them removed (gigabit +
sync). Then with the prototypes he sent me, I was able to do gigabit +
sync enabled with no errors, which is what we all want.
Around 125 feet I've got an AF24 and an Exalt G2-11 fed with
GigE-POE-APCs. Those have no issues with GigE. Not a single CRC error
since I converted the site to DC. I did see a few CRC errors on the POE
bricks that were there before. And those had *no* surge suppressors in line.
So I've got full confidence in Chuck's next revision of the GigE-APC.
Now I'm wondering if these will help at a 50kw FM site where we have
ethernet issues from time to time. Not even related to sync over power.
They're putting 17kW into a 4" transmission line with 6 or 8 bays at 500
feet. Our 450 cluster is at 230 feet. But it's only on a 10/100
SyncInjector. Three Exalt G2-11's at 110, 120 and 130 feet. Every link
sees a handful of CRC errors every day. It actually gets worse if I
remove the GigE-APCs. Sometimes the Exalts will fall back to 100Mbps,
but I think that has more to do with the flaky PHY on those radios. One
thing we've figured out is that they get a little stupid if the rj45's
aren't terminated or seated perfectly in the ODU.
On 10/3/2016 5:30 PM, Colin Stanners wrote:
I think sync over power and gigabit should not be used together.
Sync over power, while a bit hacky, is fine when the power lines do
nothing else, but trying to couple pulsating voltage with low-voltage
really-high-speed data in an RF/EMI- prone environment like on towers
just seems like a recipe for headaches.
On Oct 3, 2016 4:06 PM, "Chuck McCown" <[email protected]
<mailto:[email protected]>> wrote:
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
<http://www.packetflux.com/>
<http://www.linkedin.com/in/fwchristian>
<http://facebook.com/packetflux> <http://twitter.com/@packetflux>
