Jump to content

the toss

Installers
 View Profile  See their activity

  • Content Count

    977

  • Joined

  • Last visited

Posts posted by the toss

  4. Posted

    Lets go back to basics ( & maybe start an arguement)

     

    Firstly have a think about what IP actually is. IP is a signal transportation technique. It is not some magic camera technology. Is there any benefits of using IP in your installation? Not that I can see. Any negatives ? Well distance & power for a start.

    Price

    cable integrity

    Yes there are all sorts of adaptors /extenders you can get but these are always compromises.

     

    Now lets look at HD analogue.

    your looking at 4Mp - no problem - HD analogue currently going up to 8Mp

    runs on coax up to 500m with data control. Coax is robust & virtually bulletproof.

    you will have the same power problems as IP so if camera end power is available all the better. If not then get 24V ac cameras.

    All dvrs are networkable if that is an issue

    will run on UTP cable if required by using low cost baluns

     

    Any disadvantages in using HD analogue?

    The only one I can see is this often talked about "futureproofing" but given the pace of technology this is just garbage as far as the equipment is concerned. Whatever you put in will be redundant in a couple of years. If it is the cable that is the issue you have the following options - run UTP & use baluns with HD analogue, run coax AND UTP then use whatever you want.

     

    If you want a trouble free and easily maintained system I would use CVI HD analogue running on RG59.9 coax and use 24Vac cameras. I would run an extra UTP cable for whatever it might be needed for later and DO NOT USE RG6

     

    just my thoughts----

  5. Posted

    The cable you show is rubbish but will not cause the operational problems you are describing. Problems that cable MAY cause will be quality problems. I have seen wierd problems when a CVI camera is used on an analogue DVR.

    eg - parts of one cameras picture showing up in a different cameras picture.

    Check that all your gear is compatable .

  9. Posted

    This is what "usually" happens. You set your frame rate and resolution. This results in a recording capacity depending on the size of your hard drive. Recording is done in "blocks" - often 2Mb. So when you first power up an installation there will be nothing available for viewing until that first block of 2Mb is recorded. Similarly when overwriting , it is progressively done in 2Mb blocks. If yours is set up this way then the only way to extend recording capacity is to install a bigger hard drive or or drop your frame rate/ resolution settings.

    The other way some can be set up is to nominate a recording storage period ( lets say 30 days ) and the frame rate / resolution is automatically adjusted to enable that period to take place

  11. Posted

    Probably too late for you now but I never use bullets for outside because A) they look terrible & B) they have a really crappy mounting bracket that wont withstand objects being thrown . I always use domes.

     

    You are right about the reflected IR. It is a common mistake of novices to mount cameras as far under the eves as possible with the intention of keeping them out of the elements, but as you correctly summise , IR reflection is a real possibility. Why dont you mount them on the vertical surface of the 4x2 (left or right side depending where they are looking)

  13. Posted

    If you're concentrating on domestic systems (which are mainly entry level quality) then your biggest selling point will be warranty. That is the main thing that will set you apart from your competitors. There is not much difference in equipment cost and the labour will be the same regardless of brand. I'm in Australia so cant help with specific brands /distributors but my supplier gives 3 yr warranty on even their cheapest gear. (rebranded Dahua)

  22. Posted

    As mentioned , analogue cameras are now HD . The 3 technologies for these are CVI , TVI or AHD. They all give about the same results and are just the manufacturers formats that are jostling for market share. Personally I use CVI. Thses cameras will work on the old standard def DVRs but of course wont give HD.

    Now to your cable. For a long time I have been trying to educate people about the difference between RG59 and RG6. This information is readily confirmable on the net.

    Coax cable is designed to transport a frequency range of signals from point to point. These signals take two forms - Transmitted signals which are high level signals and received signals which are low level signals. With high level signals the shieldings primary function is to prevent spurious radiation into the immediate environment while for low level signals the primary function of the shielding is to prevent reception of spurious signals from the immediate environment. At the design point this shielding is optimised for the rejection of the expected spurious signals. This gives rise to the different types of coax cable available on the market. So what it comes down to is -

    there are cables and there are cables. CCTV baseband frequencies extend to about 5.5Mhz. Even allowing for the chroma modulation harmonics 10Mhz would be the absolute theoretical maximun. RG59 is designed to have minimun attenuation whith maximum shielding up to about 50Mhz. NOW RG6 is a relatively new coax and is designed for the digital TV spectrum which is well above the CCTV band. (>500Mhz). The shielding is specifically designed to prevent interference at this UHF freq from getting on to the low level received signal. Interference at the low frequency that would affect CCTV signals are not an issue , they are well outside the band. So when you use RG6 for baseband CCTV purposes you run the risk of low frequency interference (50Mhz<) that RG6 is not designed to shield for, causing all sorts of problems on the low Frequency CCTV signal.

    In short RG59 is designed for frequencies up to about 150Mhz (CCTV) and RG6 is designed for frequencies above 100Mhz (digital TV). THe people who sell this stuff have absolutely no idea what they are talking about. "quad shield" yeah , must be 4 times as good as single shield.

    If you are putting the effort into 900' of buried cable then you want it to work and be trouble free. Use best quality RG59 and put it in conduit (at least 50mm)

  23. Posted

    Good afternoon,

    I've searched on here for a little while, and I apologize if this question has been asked and answered. I'm a novice at CCTV so please talk to me like a young child.

     

    I live out in the county there is no a good source for internet or wifi (Line of site 3 MPS). I have a barn which has been turned into a wedding venue. For the past 3 years we used a cheap system Swann to run our security camera's outside the barn. (Longest run approx 100ft). We would like to put two security camera's out at our main gate. (approx 900 ft run) There is currently no electricity out there.

     

    I thought RG6 Siamese coax was the way to go and purchased this.. but isn't working.

     

    Any suggestion are welcome on how I could make this work. I'm willing to buy a new DVR and 2 new cameras for long run. I would like it if my old camera's would work with a new DVR and their BNC cables just to lower the cost.

     

    Thank you in advance

     

    You have two problems here. Length of cable run for the video signal and length of run for the power. Lets start with the power. The distance problem ( voltage drop ) can most likely be solved by using 24Vac cameras. These cameras have a 24Vac - 12Vdc regulator on board so effectively will allow for about a 10V drop before issues accur. This will mean new cameras as you most likely have 12V cameras at the moment. The alternative is to have an adjustable power supply adjusted to compensate for the voltage drop. The trouble with this comes with using IR cameras as the current requirements (& hence voltage drop) will change markedly between day (IR off) and night (IR on). It may prove to be an impossible juggling act between undervoltage at night & overvoltage in the day.

    Next problem is signal level. For analogue 900' is getting towards the limit. If the coax is CCA or CCS then you are past its useable length. I assume your cameras are analogue since you are talking coax cable, BUT are they the old standard definition (obselete) or the newer High def CVI, TVI, AHD etc. These cameras will have no problems running 900' on coax or Cat 5/6. The biggest difference between the two (besides price) is the physical integrity. Cat 5/6 is a fairly fragile cable while coax can just about be used as a tow rope. If it's going outside I'd be using QUALITY coax in conduit and never have cable problems again

  24. Posted

    Audio feedback is caused by an acoustic loop. Sound into mic ---> amplification ---> sound out of speaker ---> higher level sound back into mic ---> amplification ---? higher level sound out of speaker and so on. There are a number of ways to address the problem. The volume can be set to below the feedback threshold which in itself will depend on a number of factors. The physical orientation relashionship of the speaker and microphone can be changed to decrease the level of signal received from the speaker. The immediate environment can be changed to reduce (or dampen) the audio reflection from the speaker. In large sound reinforcement systems it is common to use a feedback eliminator between the mixer/preamp and the power amp. This inserts either a small time delay or a phase delay in the signal to break the resonance loop between input and output in high gain amplification.

×