Cooperman

I'm not sure when you were last over here rory, but I'm guessing the England you remember is a very different place from what it is today. Perhaps because I'm based in London it seems a lot worse than it is, but almost all private premises in the centre, whether commercial or domestic, have bars or shutters fitted, knife crime is a serious problem in schools, and although our gun culture is way behind that of the States, that doesn't mean it isn't a problem. Add to that the announcements by leading politicians and security service bosses who regularly advise us that there are possibly hundreds of potential terrorists planning attacks, and I think it's probably fair to say that the Britain of today, bears very little relation to the country it was perhaps five years ago So how do we deal with it? well, we just grit our teeth and get on with it; it's the old british stiff upper lip don't you know.

Apart from the debate about whether "CCTV" actually deters crime, which is a far more complex issue than most people realise, the problems we have over here are more of a political nature. Anti Social Behaviour and crime in general is far worse than the authorities would have us believe from statistics. We have more crime now than we've ever had previously, but for various reasons, a lot of it is either never reported to the police, or they are unwilling to record it. The suggestion that four and a quarter million surveillance cameras somehow makes the U.K. a safer place to live, is something of a 'house of cards'. We may have an embarassment of surveillance, but that doesn't mean that even a small fraction of what is in place, actually works effectively ... because it doesn't. A quick example for you; the London Underground 'metro' system is the most surveilled public transport system in the world. So on Christmas Day, a gang of graffiti 'artists' walked up the tracks from an open air station, into an underground station, where they carried out tens of thousands of pounds worth of damage. We still await the release of CCTV recordings with less than eager anticipation

Slightly off topic , but it's the same problem right across Europe. Here in London, we've got trees starting to bud, which don't normally start before March, and right across the main ski resorts in central Europe, they're reporting that they don't have any snow We've had bucket loads of rain over the last few weeks, and currently have a hosepipe ban due to a "drought". Water water everywhere, but not a drop to drink So rory, if you've been running the aircon all day, no wonder we have global warming

I just thought I'd quickly take this opportunity to wish all you folks a very Merry Christmas, and all the very best for 2007!!

Cheers for that rory, and to you and yours If your parents enjoyed Christmas in the U.K., there gonna love the New Year. It's going to be a bit breezy today Happy New Year ya'all

Hiding rory ... what do you think ... Way too much work to deal with at the moment, so sadly not much time on here these days Just to add insult to injury, I can now add a recorder to the list of recently zapped equipment. Global warming and wacky weather; another few years and we'll probably be looking at using underwater cameras

Can't wait ... I need a good laugh

Here in the U.K., there are many situations where the Data Protection Act and Human Rights Act, don't actually offer the protection that they are supposed to, so in effect, there are many opportunities for the use of CCTV, and surveillance systems fitted with audio capability, to fall outside the scope of the legislation. Just to clarify, The Information Commissioner is the regulator / enforcer for Data Protection legislation, so if their office says something does or doesn't apply, you'd have to go a very long way before you'd find anyone prepared to challenge a government department in a court of law

Absolutely spot on VST! The only slightly embarassing thing is, two weeks after I posted about lightning strikes knocking out cameras here in the U.K. being a very rare occurence, what happens ..? A few days ago I had a camera sent back for repair, a nice 12v DC powered B/W Sanyo model, fried to a crisp by a lightning bolt! You just can't make these things up

Hi Scruit, First off, you should always carry out focus adjustments at maximum aperture. I'm guessing you've got the "Electronic Iris" function switched on in the camera, so even at maximum aperture on an overcast day, you should still get a reasonable image. For the purposes of picking up vehicle plates, it is preferable to have the camera sited well away from the target area; so your 50' distance would be ideal, whereas a shorter distance generally would not be the first choice. If you calculate the distance that a vehicle can travel in the 'field of view' you may find for example that the number plate is on screen from perhaps 60 feet distance down to 40 feet. If so, (this is an example) you should place an object 1/3rd of the distance into the 'recognition zone', so with this example, it would be perhaps 47 feet (ish) from the camera. Focus on the object, then close the lens aperture a couple of stops ( to perhaps f 4 ), then assess the picture quality, both by day and night. In practice, f 5.6 would probably give you a very good daytime image, but you would need lots of light to ensure a good night view (or move your illuminator closer to the target area). As regards using IR pass filters, it will "standardise a variable" in terms of preventing the risk of focus shift that would have been present under different light frequencies, but ideally, if you were using an 850nM illuminator (for example) then you would want to use an 850nM pass filter to ensure that the maximum usable amount of IR is reaching the imager. Although many people worry about focus shift when using either daylight or IR illumination with an unfiltered lens, in practice, simply stopping the lens down two or three 'f' stops is often sufficient to offset the shift phenomenon that is a characteristic of non IR corrected optics.

That's why we've got 4.25million CCTV cameras

Karen, Generally speaking, if you put a connection into an RG 59B/U (for example) cable run (whether its a connector coupling or a well made soldered splice), then the resulting loss in signal is usually equivalent to about 20 metres ( 65 feet) of extra cable. It's difficult to be accurate, simply because cable quality can vary, and of course the quality of the connectors or splicing technique will have a significant bearing on the eventual signal loss. If cables are to be extended by a soldered splice method, then it's best to use an adhesive lined polyolfin heat shrink sleeve, to overseal the joint for perhaps an inch and a half either side of the exposed area. If done correctly, this will withstand immersion in water for many years!

Hi smpl_gy I don't know the units in question, but a couple of things to try. First off, if the multiplexer has a 'sequential' video output, or monitor out with a sequential switch function on the front of the unit, see if all the cameras are being switched out correctly to a connected monitor. Next, connect a lead from the VCR Out socket direct to a monitor, and see if you are getting a rapidly switched display of the connected cameras. If you are not sure whether they are all present, connect this lead to the Video Input of a recorder, record for 60 seconds, rewind, then play back the recording, freeze frame, then frame advance to see if each connected camera has been recorded sequentially as a coherent image. This will work with most multiplexers, but occasionally you may find one that just won't allow you to do this. If all the camera images are present, then the multiplexer is working o.k. If any are missing or showing up as a blank coloured raster, then the video is absent from that channel, and should be investigated accordingly.

kensplace, The general rule here in the U.K. is that you pretty much have to ground everything, with only a few exceptions. If for example you install a metal cased weatherproof housing with a built in heater 24v+ AC, then you will need to ground the housing. If the camera is 24v+ AC then you will need to ground that as well; if the camera is 12v DC, then as long as it is isolated from the housing, you won't need to ground it, and there is minimal risk of any earth loop being induced. Any mains powered (240v AC) equipment must be earthed, unless it is a double insulated unit (for example a plastic cased CRT monitor)., in which case the mains lead will probably be a 2 wire figure 8 type plug / socket arrangement. You can generally spot a potential (pun not intended ) earth loop situation, by looking at the length of the cable runs, and seeing if the local mains connections are fed from different distribution boards. If there is a risk of earth loop, and the equipment cannot be commoned to a specific earth point, then you will have to consider using isolating transformers to prevent the problem occuring. Despite occasional freak weather over here, lightning strikes causing camera failure are actually quite rare.

I just happened to notice a couple of interesting things happened over the weekend. The forum has just registered its 3000th member, and rory has just busted the 10,000th post milestone. Huge congratulations rory for an outstanding contribution with some excellent posting, and a pat on the back too for larry and thomas, without whom we wouldn't all be here. Keep up the great work chaps

They're like Philips V2000 but you can't turn them over

As kensplace suggested, the scan has collapsed so that's possibly either the line output transformer or transistor (or driver circuit). Not really a major fault for an experienced engineer, but most definately not a DIY job to fix. As Thomas has already said no one should ever ever ever attempt to change a CRT unless they know what they are doing. The High Tension circuit can kill a person in double quick time, and an engineer will always discharge the HT connection before doing anything else. The charge can often remain at a highly dangerous level for a long time after the set has been switched off, so don't even think about trying to save a few bucks; it just ain't worth it!!

Hi jamz and welcome, I can't comment on the specific equipment you are using (hopefully others will be along that are more familier with the kit), but performance testing is pretty much the same for any item. It's probably best to keep things simple to begin with:- Connect one single camera feed direct to a good quality test monitor, and see if the pattern is present, even to the slightest degree. If it is, it may be a transmission induced problem (or other). If it isn't, then connect to one of your large display screens and see what the result is like. Repeat with each individual camera to confirm that they are all working correctly. Only when you are satisfied with all the pictures, should you consider building up the display system in stages. It is possible that there may be some degree of cross talk or interference being caused by the display system, possibly even a minor termination problem. Good luck working your way through it!

In practice, it isn't the 850nM output which provides the glow, it's the lower (red) frequencies being output which are visible to the human eye. If a narrow band filter is used which may be quoted at (for example) 850nM, then in practice it may be passing light in the frequencies of perhaps 830 > 950nM, so whilst the camera (if sufficiently sensitive) will see an illuminated scene, we can't actually see anything coming from the illuminator. The problem is that most 850nM output lamp based illuminators (again as an example) actually output visible red light at much lower frequencies. This is great for the camera (i.e. more light available to produce an image), but what should be a covert light source, actually ends up as still noticeable by us mere humans

Hi cctv d u! Just to clarify, IR corrected lenses are designed to focus near IR frequency light at approximately the same plane as visible light, so there is no need to make compensatory adjustments when using cameras under a broad spectrum of light frequencies. If the camera is fitted with an IR "cut" filter, then little or no IR light will be reaching the imager. 'Field of view' is simply a product of focal length in relation to imager size. Adjusting the iris does not in itself have any effect on the 'field of view'. Sorry to be picky, but I thought it best to be accurate for the benefit of others reading this.

Without looking up the technical bumf on that camera, all models around that age used Video Auto Iris lenses, rather than Direct Drive optics. The connector may be a DIN socket, in which case getting hold of the correct plug shouldn't be too problematic. There are really only three conductors you need to worry about:- Red= +12v DC supply Black= 0v Ground White= Video signal To find out the wiring connections, either remove the camera cover and visually note down the wiring on the back of the socket, or if you use a multimeter, you can find the 12v supply by connecting the ground lead to the camera chassis (usually just touch the outer part of the BNC socket with the black lead), and then probe the pins until you register 12v (with the camera switched on ). Then with the camera turned off, you can do a low ohm continuity check between the chassis and the other pins to establish which one is 0v ground. Having established which is +12v and 0v, then it isn't exactly rocket science to work out which of the remaining pins is the Video signal for the lens (built in) auto iris amp. Most lens iris cables have an outer screen of very fine wires, which can be grounded to the metal part of the DIN connector ( if indeed it is a DIN). If you need any more info, just post back and I'll see what I've got lurking in the files ... Just a quick update; I had a look at some leaflets for Burle 100, 200 and 300 series cameras ( although here in the U.K., the 300 was a B/W model, not colour), and it would appear that the Auto Iris socket was also used for Ext Sync. signals. As such the connector is listed as an 8 pin DIN. If the camera does indeed have that connector, then it would be better to remove the cover (with the power off), and see if it's possible to I.D. the conductors on the solder tags side, rather than using the multimeter technique I previously mentioned.

Why not do as VST suggested and have a programmed tour for night coverage, and then perhaps use a photocell (wire across the NO relay output), to initiate an alarm state only during the day. That should hold the camera on your alarmed view during daylight hours, although depending on the control system being used, there may possibly be other options.

Hi kensplace, It would be relatively easy to install earthing points (one for the main case, and one for the cover) using threaded bolts, nuts and shakeproof washers (perhaps M6) and earthing wire soldered to some terminals. Without the earthing connection, if the insulation failed and the case became live, then the fuse in the mains plug probably wouldn't blow (unless the person or whatever touching it, created a mains path ). It may be better to fit a low voltage resistor anyway, or possibly a small fan, particularly as the amount of damp air inside such a large housing, will invariably hold a lot of moisture which would just love to condense on the housing window (given half a chance).

Hi White Fox, Bit of a walk from Wiltshire, but you could try contacting this company:- http://www.jwfasteners.com/ They list 1/4" BSW in studding, so maybe they do nuts or bolts as well?

A pair of polarising filters That way, you get a variable ND effect, although it can be very expensive if you drop them