deano2106 0 Posted October 27, 2014 Morning All, it's my 1st time posting here & hoping I've posted in the right board..... I'll try to not make my problem long-winded. Basically, i have a securix wired CCTV system for my business, with 2 camera's on the front & 1 inside the building watching over the entrance....these 3 are wired & all work fine.... Due to expansion i have just acquired a small unit opposite mine for storage, this unit is directly facing the entrance to the yard so is a brilliant spot to place my 4th camera, however due to the unit being detached from my other it cannot be wired. So i did a little reading up & come across this from Maplins... http://www.maplin.co.uk/p/sentient-420-tvl-wireless-indoor-and-outdoor-camera-with-15m-night-vision-n12cx A wireless outdoor camera with a wireless receiver, with capabilities of 100metres clear line of sight - perfect! I also read up that the metal building will weaken the signal upto 90%, so to overcome this i bought a weatherproof plastic outdoor terminal box big enough to comfortably fit the receiver inside, i then used my spare camera cable & adapters (BNC) to connect the wireless receiver to my DVR box. Note that the distance from the camera to receiver is approx 20 meters clear line of sight, with both camera & receiver @ the same height. I have tried all 4 different frequency settings, played with the antenna's, DVRs settings etc & it's hopeless! Am i right in thinking that the frequency is too weak? The image is constantly flickering & dropping signal, every now & again the image stabilizes but as soon as a vehicle passes through the gates it goes again - which contradicts the whole point of the camera been there. Any help, advice, links etc would be greatly apprecaited, before i set about it with the hammer Many thanks in advance. Dean. Share this post Link to post Share on other sites
the toss 0 Posted October 28, 2014 You don't say where you are. Regulations for wireless are different everywhere. I'll give you some general info which may or may not apply to you. Most wireless gear you will come across utilises the "free" public access frequencies. In Australia these are 2.4Ghz , 5 Ghz & I think another at around 8Ghz & PEP (Peak excited power) is limited to 10mW. This is a pretty useless amount of power in real life scenarios & ANYTHING that gets between the transmitter & receiver is going to cause signal dropout. In rain it will not work at all. You have made a good move by mounting the RF gear outside the metal sheds but that is only part of a possible solution. You are probably using a fractional dipole antenna ( a little "stick" antenna about 3" long) This is a omni-directional antenna & radiates in a 360* pattern which is very wasteful when you only have 10mW to play with. A high gain "directional" antenna like a yagi or stacked beam array may be enough to solve your problem but they would still need to be high enough to give clear line of sight. In America you can get high powered RF gear designed for CCTV signals. I've seen stuff up to about 10W with a "advertised" range of 30Km. If this gear is not available to you then antenna tuning will be your best bet. Share this post Link to post Share on other sites
deano2106 0 Posted October 28, 2014 Hi there. Sorry for not mentioning before, I am in the uk. Also, everything is mounted to the exterior of the building so that the signal doesn't have to battle through the metal cladding, but you're right re the Ariel, a small 3" antenna is what they both have....and they are both clear line of sight so they are virtually looking at each other. Do you think the larger antenna would be an improvement? Thanks Dean. Share this post Link to post Share on other sites
MichaelDelarosa 0 Posted October 28, 2014 The image is constantly flickering & dropping signal, every now & again the image stabilizes but as soon as a vehicle passes through the gates it goes again - which contradicts the whole point of the camera been there. Any help, advice, links etc would be greatly apprecaited, before i set about it with the hammer Many thanks in advance. Dean. Try to adjust both the brightness and contrast settings on the device and move your camera to a different location. Location is also one the many factors the image is constantly flickering & dropping signal. Share this post Link to post Share on other sites
the toss 0 Posted October 29, 2014 The image is constantly flickering & dropping signal, every now & again the image stabilizes but as soon as a vehicle passes through the gates it goes again - which contradicts the whole point of the camera been there. Any help, advice, links etc would be greatly apprecaited, before i set about it with the hammer Many thanks in advance. Dean. Try to adjust both the brightness and contrast settings on the device and move your camera to a different location. Location is also one the many factors the image is constantly flickering & dropping signal. Michael has a good point. Radio waves , by their very nature, will cause "null" spots where the radio wave arrives at a particular spot after travelling via two (or more) paths and may be out of phase thus cancelling the signal. You may find that simply moving the transmitter OR receiver just a metre or so will overcome your problem. Unfortunately constant vehicular movements in the vicinity will result in these nulls moving all over the place so the problem will probably persist. Being in the UK you will be screwed worse than we are when it comes to wireless stuff. I have seen designs for homemade hi-gain yagis for 2.4Ghz on the net. Share this post Link to post Share on other sites
