Re: Camera on Power-Line Adapters

[E D <napinc7@xxxxxxxxx>]

Hi Les,

Glad to hear that it worked for you except for when the sign is on...minor =
details.

I found this link: http://ieeexplore.ieee.org/document/6814439/?reload=3Dtr=
ue titled "The influence of fluorescent lamps with electronic ballast on th=
e low voltage PLC network. The PLC being the PowerLine Channnel.

It appears that the PLC can be easily affected by the lamps. That is not so=
mething that I was aware of, nor have experienced before. I even found an a=
rticle about an illegal pot grower who was using high power fluorescent lam=
ps for growing and had the "Interference Police" (the local internet compan=
y's Interference Tech) knock on his door. His growing operation was affecti=
ng Internet communications for the neighborhood!

Quoting from the article, "In the (3kHz-150kHz) the interference level from=
 fluorescent lamps is significantly below the allowed maximum PLC signal le=
vels. In the 150kHz-30MHz band however, PLC signals compete with Electromag=
netic Compatibility (EMC) levels.

Basically, fluorescent lamps on- PowerLine Channel compromised.=20

It should be possible that by having an isolated 120vac line for the video =
and powerline adapters, that this would provide enough isolation for the er=
rant and unwanted interference. There may also be a possibility that the fl=
uorescent "radiation field" could still interfere with the PLC channel, but=
 that should be to a lesser extent. If this happens, you could isolate eith=
er the ballasts or your equipment at the sign, or both, with an EM shield. =
Much like shielded CAT5 wiring that is wrapped with foil, you could outer-w=
rap your wiring and anything else that you deem fit, making sure that you w=
ill not be causing any
heat-accumulation to any wiring or equipment.

You would also want to look at any interference being caused at the other e=
nd of the line, where the other powerline adapter is- in relation to the wi=
ring that goes out of the building to power that sign. Just because a/c pow=
er is flowing out to the sign, interference is not limited to one-way. The =
EM field of the power wiring could carry an interference wave and also be a=
ffecting the other adapter. A radiation shield could be also needed there. =
Also, if there is any type of power-switching equipment at the building end=
 for any other sign, I would take a look at that also.

I carry an electromagnetic field apparatus that will detect any fields in t=
he x,y,z axis. It has been very handy in the past. There was a customer wit=
h a cellular radio on his alarm system, who suddenly had communication prob=
lems. I went to his home one evening, and sure enough, the signal strength =
was way down from the original installation. I took out my 'voodoo' apparat=
us and noticed that there was strong interference coming from around his te=
levision which was only about 8' from the radio. I asked him a few question=
s about if anything had changed in that location. He said that this was the=
 same tv as before. I persisted and then the light came on in his head, and=
 he admitted that he had just recently bought one of those flat antennas fo=
r his tv in order to get local channels. I had not noticed it since it was =
flat and not readily identifiable. Sure enough, he took it down and cellula=
r signals were restored. You just never know what could be causing interfer=
ence.

I am sorry that you have run into this problem, but persistence will win in=
 the end. It appears that you have a very healthy dose of that.

...In jest, maybe you could just provide the owner with a remote app to tur=
n off the sign when he needs to view the camera!

E D