POE Security Cameras destroying my VHF Lo Reception

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empireco

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My Lorex HD security camera system has been destroying my VHF Lo reception for a long time now.
I recently changed from the factory supplied cables to the cameras to shielded Ethernet cable and connected all the shields to a 14 gauge wire that runs strait to the negative on the 12 volt power supply which is also hooked to the House ground. I rerouted several cables to get them as far away from my radios and coax feeds as possible. That did not stop the interference. When I unplug all the Ethernet cables from the Lorex NVR or switch the power off, the interference disappears.

Does anyone have a suggestion to eliminate the interference besides stopping using the system?
 

prcguy

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Yes, my POE cameras made a lot of noise on HF but I never checked VHF lo. The cameras seem to make the noise and the Ethernet cables are the antenna, you need to kill the noise at the source. Grounding will not do much as the ground wire just becomes more antenna.

I used 1" inside diameter #31 mix snap on ferrites on all the cameras and my noise is greatly reduced. You would have to experiment with the number of turns as I needed more for the lower frequencies and I think I used five or maybe six turns. I also run all the cables through more ferrite at the NVR, which has built in power injectors. Here is the best prices I've found on the huge snap on ferrites.


I have just a tiny bit of noise humps through 40m and 80m where I participate in some nets and it can cover up the really weak stations, so my final solution was to put a remote controlled switch on the NVR. When I'm home or even traveling using my HF rig remote I can turn the system off to get the very lowest noise floor. I suspect more ferrite would fix it but I took the lazy way out.
 
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belvdr

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Are you using PoE injectors? If so, I’d recommend getting a PoE switch instead.
 

empireco

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Thanks for the repiles, I'm using the cameras Directly into the Lorex NVR which provides the power, no need for a switch.

I knew there had to be a way to have my cake and eat it too so I tried something else.
I believed the interference was coming from the cables and getting into the long coax run (antenna is a an AR-6 Ringo at 120 feet),
so I replaced all the shielded Ethernet cable which I cut to length, with very, very long unshielded cables that came with a security system that I had previously considered useless.

I left these cables at the insane length and left two large coils of cable both at the cameras and the NVR.

This seems to have done the trick!!! I'm so happy PTL!!! The interference has all but disappeared!
only about an S2 on only a few freqs and some stronger around S4 but only on very limited freqs instead of the whole band being pegged with noise every few KHz of tuning.

Hopefully this will help someone else.
Apparently shielded Ethernet isn't shielded very well.
 

a417

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This is not the product's problem, it's your implementation.

From another site for some reason I can't link correctly due to COVID-19 said:
There’s one other standard to be aware of for shielded cable installations, the ISO/IEC requirement that shielding must be complete for an entire channel. In other words, you can’t mix shielded and unshielded cables, connectors or network controllers. All of the components must also be shielded and grounded, if you are using STP or FTP Ethernet cables.
There is the good possibility that correct complete implementation would give you vastly different results.

Do you really think cheap chinesium components found in most ebay-grade cameras meets ISO/IEC? Does your entire installation meet the requirement? Not taking a shot at you, but it probably falls short.
 

prcguy

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There is no correct implementation, the cameras make lots of RFI and its not confined inside a shielded Ethernet cable. The outside metal housing of the camera is hot with RFI and so is the outside shield of shielded Ethernet cable. More shielded cables in the system is simply more antenna to radiate the RFI. Its a common mode current problem and the only realistic solution (for me) is a good application of ferrite.

This is not the product's problem, it's your implementation.



There is the good possibility that correct complete implementation would give you vastly different results.

Do you really think cheap chinesium components found in most ebay-grade cameras meets ISO/IEC? Does your entire installation meet the requirement? Not taking a shot at you, but it probably falls short.
 
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empireco

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This is not the product's problem, it's your implementation.



There is the good possibility that correct complete implementation would give you vastly different results.

Do you really think cheap chinesium components found in most ebay-grade cameras meets ISO/IEC? Does your entire installation meet the requirement? Not taking a shot at you, but it probably falls short.
I don't agree...

The proof is in the fact that the interference is gone.

I used shielded cable with shielded RJ45's and GROUNDED the shield. I happen to be a 2 year Associate Electronics Engineer so I know here you are coming from. Although not a RF Engineer (like I wish I was), the cheaper cable solved my problem and I fully believe that either the product (cable I bought) was faulty (not properly shielded) or the shield is intended to only protect the cable from receiving RFI not emitting it.

Any way, I'm glad the problem has been solved. I've been sitting here all night monitoring with no more static on VHF Lo and even managed a copy on a Stone Company from Lexington, Kentucky today on 47.440 118.1 PL which is no small accomplishment due to distance from source transmitter and the fact that it was not a skip catch.
 

spacellamaman

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so my final solution was to put a remote controlled switch on the NVR. When I'm home or even traveling using my HF rig remote I can turn the system off to get the very lowest noise floor. I suspect more ferrite would fix it but I took the lazy way out.
jeeezzzz.....lazy? i dunno, but it sure ain't un-complicated. i bet Tesla would think you were out of you mind.
 
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