the toss

OK , my brain has Google stress . It seems that where there was once order , chaos now prevails. Apparently the ONLY certainty is that RG stands for "radio guide" (coax). The identification numbers following the "RG" are mostly random , arbitary & have no rhyme or reason. There are some manufacturers that attempt to adhere to the standard as it once was but they are few and far between. This is a brief description of how it USED to work. examples - RG59 - RG means coax 59 means Zo=75^ this cable conformed to a standard set of published characteristic guidelines. Suffixes - M (RG59M) - military spec U (RG59u) - suitable for UHF (meaning it wasn't the best for lower freq) I think there was another suffix that described the outer sheathing (B= burial A= aerial) RG58 - RG = coax 58 means Zo=50^ suffixes the same as above It would seem that it has all been dumbed down & the RG number simply describes the physical characteristics of the cable rather that the electrical characteristics. If my memory doesn't fail me I seem to recall that the ARRL handbook had an excellent description of coax nonclomenture. Needless to say I will cease advising against RG6 and concentrate my comments more on the shielding construction.

Jazzar - you are messing with my brain. Maybe everything I've learned from 20 years as a microwave radio engineer is wrong ( or maybe the Chinese technocrats have developed their own set of rules) It certainly does warrant further investigation & if I'm wrong then I will eat humble pie. The characteristic impedance was ALWAYS one of the prime definers of a coax cable before you went to the secondary technical characteristics. If this is true then I don't know what to believe any more.

Power related earth loops are also reduced but I would ask bentech about his cabling. What is he using & how long are the runs? It sounds to me that it is not an earth problem but a vertical sync problem.

No, what I hear is RG6. RG6 is a grade of cable manufactured to a certain set of parameters. RG59 is a different grade of cable manufactured to a different set of parameters. Each cable can be manufactured using copper or ccs or cca and as long as it meets the defining characteristics of the grade (RG6 , RG59 etc) there is no problem. All it means is that we have a cable that is top quality or a cable that is low quality however both will meet the determining characteristics. As I said it is only unsuitable in the wrong environment. By the time you find out it may well be too late. That is a bit like having a Ford that is designed to be a Volvo - it doesn't make sense. Like I said before it has nothing to do with having a solid copper core or 95% shielding - it is the design of the shielding that matters as well as all those other characteristics that define the cable like dielectric capacitance, velocity factor etc. I would question his desire to use HD-SDI (which was designed for getting HD around broadcast studios ) rather than using HD-CVI or HD-TVI both of which give IP quality pics at a fraction of the price of HD-SDI. HD-CVI & HD-TVI will also carry audio & control datd for PTZ should it be required. Max distance for HD-SDI is 100m on top quality coax HD-CVI & HD-TVI is around 500m.

The problem is this. The shielding on coax cable is essentially a Faraday Shield surrounding the active inner conductor. Now Faraday shields cannot exclude the total spectrum of RF frequencies , they are designed for a specific range in the spectrum. Similarly , shielding aint shielding. Shielding is designed for a specific range of rf exclusion. RG6 , being designed for mainly digital RF frequencies, has had its shielding designed to prevent high frequency interference in the range of interest (80Mhz & above). Now CCTV baseband signals are at about 5Mhz. This frequency is well outside the digital TV band & would have been irrelevant in the RG6 design stage. So the noise rejection properties of RG6 is quite poor at the CCTV frequency of 5 Mhz. Similarly using RG59 for Digital TV antennas presents the same problem in that RG59 has poor noise rejection properties at digital TV frequencies. It can , and has been used for cctv but unless you are sure about exactly what spurious EMF interference is in the area you won't know how it will perform until it is installed & the system fire up. Some may be willing to take the risk but as one who earns a living from this type of work I won't take the risk. So if you take the time to do some research the bit to concentrate on is the shielding.

Horizon , I wish you would stop telling everyone that it is fine to run RG6 - it isn't. If they happen to have a roll of RG6 lying around & want to try their luck then go for it. BUT if these people are starting from scratch & want to use the CORRECT cable then you are misleading them. I will dig up some links that explain the deficiencies of using RG6 for CCTV. http://www.abccables.com/info-rg59-vs-rg6.html

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.

Which is why you SHOULDN'T use RG6. RG6 MAY work ok but you won't know until all the cabling work has been done & the system fired up. I have seen RG6 used after being advised against it & finding the picture was un-useable. The look on his face when he realised that it would ALL have to ripped out was something to behold.

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.

I agree with TGMcCallie, the bull that you were told sounds like an idiot excuse justifying why they use cheap CRAP. How can he see where the signal travels? Where did he get this C0ck & Bull story? He likely made it up. pure copper is more expensive thats the ONLY reason anyone might use it. Copper requires careful handling it's true but should be malleable too so it can take some punishment during installation, problem is if you make a long run of copper cable and test it and it has a break it's a pull and replace so careful handling is essential. Have you considered using Cat5 with baluns ? Same Principal applies just use solid copper conductors. You can send the signal upto 1000 ft without amplification and further with active baluns. This phenomenom(?) is called the "skin effect" but only becomes apparent at around 100Mhz & above. So as I constantly tell people that RG6 is designed for HF RF signals , you can get away with short runs of CCS for TV signals but not for CCTV which operates on a baseband of around 5Mhz. For CCTV it has to be copper RG59 with high density shieldin or UTP with baluns. Personally I prefer RG59 but have used UTP on occassion.

It says "H264 Digital Video Recorder" Most of these DVRs are pumped out of 3 or 4 factories and are simply rebadged to suit the major customers requirements.

Get a device that does support "Push Video"

I have heard of HD-SDI and HD-CVI but not HD-TVI. What is it ?

The camera will set it's own ambient temperature within the housing. It's self warming. The biggest danger is if power is removed & re-applied numerous times thus causing physical stress on the components

So an eletrician isnt even needed to wire walls with ethernet which you will run POE? I mean my brother in laws dad does this kind of work so I was going to use him anyway but I figured that w as required. THanks again for the answer. So that would be your father in law

This is only MY view on the subject. Box Cameras - can be fitted with large lens needs enclosure for outside use would not normally use in a residential situation generally not very vandal proof if mounted low Dome Cameras - generally limited as to the lens size (12mm) more compact than box cameras slightly more vandal resistant if mounted properly Bullet Cameras - much the same as box cameras but don't need an enclosure the cheaper ones come with very poor mounting hardware Ball Cameras - my favourite for residential applications compact & vandal resistant if mounted properly usually limited to 12mm lens because of physical constraints

The external lens/cover. It is there to protect against scratches. Keep in mind that 2cif recording resolution is NOT hi-res, it is low quality BUT that won't affect the live view.

Check that the plastic protective film has been removed from the lens.

The screen shot of the main menu is of no help at all. Every second DVR will have a menu the same or similar to that. The manufacturer would've been more help, OR (as I am guessing) there is no brand name on it. Another dirt cheap no name knock off that gives unsatisfactory results. Most DVRs will record until the HDD is full & then either overwrite or trigger a HDD Full alert. Most DVRs will do all the other things you want (even the cheap ones) Have you checked in the manual that came with the recorder?

You guess right But this is basic stuff you should be able to find out for yourself.

RG174 ( commonly called mini-coax ) is not suitable for cctv baseband transmission. It has a characteristic impedance of 50^ and is most commonly used for GSM , GPS etc anntena cable utilising SMA/B connectors.

On the better quality DVRs you can program a number of cameras to cycle through the spot monitor. I would be looking into the spot monitor programming to see what is going on.

What field does your "engineer" practice in. RG6 is NOT designed for cctv baseband - he should know better.

A good quality 480 tvl 1/4" camera may well out perform an ordinary/low quality 700 tvl 1/3" camera as it is NOT as simple as "bigger sensor & more tvl equals quality" Many manufacturers lie about the tvl ( you have no way of checking ) Many manufacturers use acrylic (plastic) lens's instead of optical glass Many manufacturers have little in the way of processing electronics in the camera When you say you have not seen much improvement in the video quality are we talking recorded video or live video ( or both ) The live video is simply a split of the signal from the camera BUT the recorded video has undergone compression by the codec in the DVR. So your recorded quality may be limited by the DVR you are using NOT the camera. Cables - poor quality cables can cause high frequency signal loss from low dielectric quality. poor quality cables can cause low signal level fro high DC loss ( aluminium & steel ) poor quality cables can result in low noise rejection ( aluminium / steel shielding, low shielding density , etc) Do NOT be tempted to use RG6 , it is designed for UHF RF frequencies & its shielding properties are NOT the best for 5Mhz cctv baseband frequencies. Hope this has been helpful

As Don has said , reverse polarity will simply affect picture quality and cause no other ill effect. The camera only puts out a 1 volt signal , not enought to "pop" anything. You have either incorrectly wired something or your DVR has had a catastrophic failure & fed voltage out to the cameras.