My site is a GigE PowerInjector+Sync. No changes to the jumpers. Took it
out of the box, plugged it in. The injector shows 23.9 volts (from a RSD
48 to 24 converter) on PowerA. PowerB has nothing connected. Two 5GHz
450 APs on ports 1 & 2, two 3.6GHz 450 APs on ports 3 & 4. ~225 feet of
shielded cable to each radio.
I would assume the same. Probably would be worse on 48/56v. I wouldn't
expect this on 24V systems though. I believe Matt said his setup is a
GigE SyncInjector, GigE-APC-HV's and PTP-450i's, which would definitely
require 48-56VDC. 450i's need at least 40 volts at the radio, IIRC.
I just confirmed this at another site where we added a GigE
PowerInjector+Sync with two 5.7 450 APs and one 3.6 450 AP. Slightly
less cable, about 185 feet. The 3.6 AP doesn't have an in-line SS yet.
Radio direct to injector port. Ethernet directly to a RB1100AHx2 port. I
just powered that AP back up and switched it to negotiate 1000F. Main
status page shows 1000Base-T FDX and receiving sync on the power port.
MT port shows 1Gbps FDX. No errors. This one is fed similarly, just
regulated 24VDC on PowerA. The two 5.7 APs are on older L-com 10/100
suppressors, so obviously I can't test gigabit on those.
So yeah, I can pretty much confirm what Matt is seeing. The sync pulse +
GigE-APC-HV in line appears to be the culprit. Am I remembering that
Chuck said the GigE HV's clamp at 69 volts on all pairs? Seems like that
should be enough headroom for 24VDC + the sync pulse. Perhaps the cable
length is pushing it over the edge.
I believe negotiation takes place on the 10/100 pairs only? Then the
radio's PHY has a feature called Ethernet@Wirespeed. If it doesn't see
data (or in this case loses I guess) on the 4/5 and/or 7/8 pairs, then
it gives up on GigE and falls back to 10/100 negotiation. That's why the
link is bouncing at 1Gbps a couple times at boot and then settles on 100
FDX. SS clamps due to the sync pulse. No gigabit for u!
On 9/10/2016 4:30 AM, Forrest Christian (List Account) wrote:
Just curious... what voltage are you feeding into the injector?
I wonder if maybe if you're starting at 56V, then adding a bit of
inductive surge effects due to the cable and sync pulse thing. I
could see this surging into 60 volts for sure... not sure where
Chuck's suppressors clamp at.
-forrest
