Hi, I've the same issue in many systems I realized, the image suffers of flickering, and it is related to the HDD writes, each time HDD writes a flick appears on all cameras, usually the ones with longer distance have a bit less of that.
I am using a 12V 10A PSU with a 17Ah battery connected, this ensures me about 5/8 hours of surveillance when the power goes off, this creates the problem with the common ground, I'm aware of itm but using different PSU as somebody suggested needs a UPS, which has only few minutes of working time. Buy another PSU with battery increases costs and maintenance costs when it will need to replace batteries, it would better not doing it.
Analog cameras, connected by baluns on a 4 pair FTP cable, 3 pairs are used for power, one pair for video signal. On the DVR side (only) the shield of FTP cable is grounded with all other cables.
Touching the power concept isn't an option, since requires too much time and I really dubt it can help significantly.
I usually place on the DVR poer line a ferrite with many coils wrapped on, 2 coils exactly with same orientation (to have zero flux as result), one for positive and one for negative wire, and added 0,1uF capacitors too, this usually reduces the effect but not eliminate it. I've also tried to put it internally on the HDD power cable, to insulate the noise between HDD ground and DVR ground, but not great results.
What can I do? probably a DC/DC 12V/12V with galvanic insulation will solve the problem, I don't know if I can find cheap ones, any other suggestion? Thank you!
I am using a 12V 10A PSU with a 17Ah battery connected, this ensures me about 5/8 hours of surveillance when the power goes off, this creates the problem with the common ground, I'm aware of itm but using different PSU as somebody suggested needs a UPS, which has only few minutes of working time. Buy another PSU with battery increases costs and maintenance costs when it will need to replace batteries, it would better not doing it.
Analog cameras, connected by baluns on a 4 pair FTP cable, 3 pairs are used for power, one pair for video signal. On the DVR side (only) the shield of FTP cable is grounded with all other cables.
Touching the power concept isn't an option, since requires too much time and I really dubt it can help significantly.
I usually place on the DVR poer line a ferrite with many coils wrapped on, 2 coils exactly with same orientation (to have zero flux as result), one for positive and one for negative wire, and added 0,1uF capacitors too, this usually reduces the effect but not eliminate it. I've also tried to put it internally on the HDD power cable, to insulate the noise between HDD ground and DVR ground, but not great results.
What can I do? probably a DC/DC 12V/12V with galvanic insulation will solve the problem, I don't know if I can find cheap ones, any other suggestion? Thank you!
