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tube tech

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  1. tube tech

    Distortion on certain cameras

    that looks like an open shield on the coax. always at the connector that's hardest to reach open center conductor >> no video open shield >> video finds ground through another path, but it's noisy
  2. about that "you should never solder coax" research "install PL-259 connector." anyone doing high power RF solders the connector. you did get bad advice, but it's not what you think it was.
  3. if they come with CAT5 cables, you don't need more if you may install another network device at or near the camera in the future, installing CAT6 may save you work in the future but if you continue on that line of thinking, you should pull fiber optic I would pull the CAT5 on hand, and multi mode fiber
  4. tube tech

    nvr and dvr camera questions

    those converters probably do not convert the signal format. they provide an interface so the signal can be sent over CAT5 cable, and at the other end, they convert back. they interface the video signal to the CAT5 cable. we would need to see a link to verify this if they look like this, they are baluns, not signal converters https://www.ebay.com/itm/LOT-CCTV-Coax-BNC-Video-Power-Balun-Transceiver-to-CAT5e-6-RJ45-Connector-US/303066208877?hash=item4690275a6d:m:mG0qV4NnSFl3pECiiLVFv_A
  5. tube tech

    Black Wavy Lines

    that has a name: ground loop. two grounds in the system are at different levels. in theory the cure is a video isolation transformer. none of the ones I tried ever helped a bit. verify that both ends of the coax have good grounds.
  6. tube tech

    Camera placemnt - on or off building?

    eye level for face recognition, at the end of a corridor where they have to walk right at it. 3.6 mm focal length or higher. lower numbers distort too much. cameras in windows give you a prolonged mug shot if they pause and not enough to recognize if they walk past 8 feet up if you want to know that someone is out there, but not necessarily who. 1.7 mm to 2.8 mm lenses I mounted two cameras on my front porch, facing the house, in a crossfire, if you are on either you are on both. if you think you are hiding against the wall, I got your profile from both sides. 2.8 mm lenses I have two outdoor cameras mounted in bird houses. birds actually built a nest in one of them. this is an improvement over the previous hornets nests. cameras on the outside looking in present cabling headaches.
  7. tube tech

    How to enhance cctv footage

    1978 Westphalia. sucked $8,000 from my bank account. not one tiny bit closer to running. everybody who drives by wants to buy it for chump change. every one of them too stupid to comprehend that they would not be buying an unrunning VW, they would be buying an unrunning VW and $6,000 worth of parts they would have to buy to get it running.
  8. tube tech

    Body cams are not discrete enough

    the real problem is that you can't get them to sit at a useful angle. they rotate to where you get a superb view of your right elbow a second aggravation is the sound. the person who looks like your right elbow sounds OK, you sound like BLARFGOKLEMUMBZZT because the mike that picks up the other party overloads from your too-close mouth
  9. the last time a car alarm went off around you, did anyone scream "Oh my God, somebody call da COPS!" I didn't think so. burglar alarms do not alarm burglars, but they excel at annoying neighbors.
  10. tube tech

    50 Ohm BNC vs 75 Ohm BNC

    most 50 ohm is RG-58. Most 75 ohm is RG-59 or RG-6. physical specs can be googled. RG-58 & RG-6 should have one center conductor, RG-58 has many strands The physical specs are considered to be more of a guideline than a contract in many asian countries. ebay BNC crimp on connectors don't crimp right on CCTV siamesed cable, which is apparently RG-58 1/2 you could make a TDR with a pulse generator and a scope. If you have to ask, don't bother, it would take way too long to explain If you have a big spool of cable, connect the color bar generator to the monitor and the spool, with a T on the connection and a 75 ohm load on the far end of the cable. It it's 75 ohm cable, no reflection. It it's 50 ohm, you get a ghost image down and right of the real image 50 feet of cable is enough to see this effect
  11. brand names are essentially meaningless. they are all made in People Factory 43, somewhere in China. check out cameras on eBay & Supercircuits: same picture, price ranges from $7.39 to $197.39 for the exact same camera.
  12. this is one of very few instances where 5.8 ghz wireless is practical. the range limitation is not a problem, the bandwidth is mostly unused
  13. tube tech

    DVR and NVR?

    my junior high math teacher would say that NVR is a subset of DVR, draw a circle in a circle, make them different colors.
  14. tube tech

    Wireless HDMI and other things

    you can see the NVR over IP. I feed the composite video to Channelplus 5545 modulators to make all NVRs visible on all TVs. I bought the CCTV system from an apartment building off of eBay, learned a whole new skill set.
  15. tube tech

    Tips for mounting cameras behind glass?

    I have two. Hornet hell. imagine a hornet landing on a 1.8 mm wide angle lens, seen on a 52" TV. a hundred times a day. looks like a danged eagle. you have to seal the birdhouse, put a plate or screen around the opening. not difficult, but it's better to do it before the softball sized nest of stingy things shows up. black towel over the drapes kills reflections
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