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the toss

Installers
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Everything posted by the toss

  1. As Servtech has mentioned the balun is for impedance matching & unless they are the upmarket ones will have little effect on the induced noise. Why not use STP cable (shielded twisted pair) like Belden.
  2. the toss

    CAT5 breakout technique?

    [quote="J- I'd like to but that's a lot of ugly cable down the hall. I'm hoping that one run can be placed without making things look too bad. Outdoors that would work fine. You're not running the cables along the floor are you ?
  3. the toss

    IP Rated Enclosures for Outdoor Use

    I have lots of installed cameras around marinas & waterfront properties & corrossion is a constant problem. Some are on a half yearly maintenance contract & regularly get cleaned as well as the mounting / adjusting hardware lubricated with marine grade grease. There is nothing worse than ( come replacement time) you cant even undo the mounting bolts. Even the Chinese stainless steel pits & stains from the salt.
  4. the toss

    Most versatile audio solution to this application?

    Had a look at the specs for that amp & a few things stand out. I cant see a stated RMS power output only a TOTAL power output of 560W ( 2 x 280W @ 10% THD [total harmonic distortion] 120 - 10khz) The 10% THD is telling me that the stated o/p power is peak level not RMS & at 120 - 10khz it is hardly Hi-Fi. However all is not lost. 560Wpp equates to just about 400W rms or 200W rms per channel which is a fairly useable o/p but that is flat out at 10% THD. Drop that o/p back by 20% will give 160W rms /chan at close to 1% THD. Now we arrive at the realistic useable power. The unit as it stands is quite adequate for domestic use unless you are one of those "oxygen free copper" speaker lead types. The problem now becomes your speakers. Those 6" cones aren't going to move a lot of air & it is this that is critical in sound transferrence. This is the "sound pressure level" (SPL) & is usually a quoted spec for most speakers in db/metre @1W. It is a spec that manufacturers of units like yours are reluctant to provide & for domestic use it really doesn't matter very much. The victim of adequate o/p power but poor SPL is clarity, you will hear the sound but it will be hard to understand. Not what you want if there are to be speeches. If you go ahead with buying this amp I would dump the speakers for your wedding & hire a set for the day from a PA/audio store. Find some boxes with a 15" bass , 2 x 12" mids & a reflex horn or a couple of piezo tweeters. Whatever the configuration of speakers it is important that each box is 4^ total load. Get 4 boxes (two for each chan). Cable each pair in series for a total load /chan of 8^. This will give you a lot of scope as to the placement of the speakers & ensure a good outcome. If you go the hire speakers path you would be best consulting with the hire store, they will probably be only too ready to help.
  5. the toss

    Most versatile audio solution to this application?

    It would be interesting to know if your option #1 is 560 "real watts" or chinese watts. To be honest most people now days would have no idea just how loud 100 real watts is. I think that for your venue ( & later domestic use) you should ensure you have a good graphic equaliser with whatever you end up with. The requirements at your wedding venue will be different to that in your loungeroom. Your loungeroom will be quite a bit smaller with lots of sound dampening soft furnishings. The bass frequencies will be heavily absorbed & the highs will not need a great deal of disperssion. On the other hand , at the venue the bass will echo & will need to be cut back while the highs will be lost to everyone not in front of the speakers. The highs are fairly directional & is why the horns are usually set up in a radial array in the large PA systems. A good honest 150W amp , 32 band graphic & flexible speaker arrangement would be your best option. Congratulations on the marriage.
  6. Well it's not going to be all that unobtrusive with a camera & junction box mounted at various points around the house. It sounds like all the cameras you are using have flying leads on them that will need to be kept out of the elements. On domestic installations I usually mount to the eve with the connection point inside the eve.
  7. the toss

    cut the wrong connector

    After you solder the wires on , make up a tube of cardboard that goes over the solder connections then fill it up with a hot glue gun. As good as the original.
  8. Ohms Law 101 - If the voltage decreases & the resistance stays the same then the current will DECREASE
  9. the toss

    Cat5 baluns

    You can simply connect the extended cable to your existing one BUT - 1) make sure you solder the joint 2) Make sure you use the same pair ( they have differnt twist ratios ) 3) Make sure you join the right end of the extended cable to keep the twist in the same direction 4) You may experience some signal degradation depending on the length of the run 5) Make sure it is waterproof.
  10. the toss

    Pimp my eyeball cam

    Excellent job
  11. the toss

    Newbie shield question

    That is a technique to eliminate earth loops often used in audio setups & can be quite dangerous. It is earthed at one end to provide EMR shielding while the signal return uses the power earth. By breaking the shield earth you are breaking the earth loop between two pieces of equipment . eg mixer & equaliser
  12. the toss

    cable question

    If your power sources are 100' apart then it could well be an earth loop problem. BUT the A/V shielded cable you have used could also be the problem. 100' of sh*t cable is just asking for problems.
  13. the toss

    Night cameras???

    Your TV is only displaying the signal it receives from your camera. Obviously with adequate light you get a reasonable picture. So it would seem the problem is signal quality when operating under IR conditions. Have you checked the camera voltage when the IR is on ?
  14. the toss

    Power wire splicing

    He is the type of guy that I am always following around to fix his poor workmanship
  15. the toss

    Power wire splicing

    You mis-understand me. Stranded wire is what should be used. Those connectors are for solid core wire & should not be used.
  16. A ground loop occurs when a signal has two different paths to ground of differing potentials - which most often means, two very different resistances. It causes the line to behave like an antenna, picking up all manner of interference and electrical noise. . That can be an issue in audio installations where a common earth loop fix is to unearth one end of a low power transmission medium (eg a mic cable) but not usually the cause of interference in camera systems. What the problem really is as you say is the different earth potentials. Any differing potential will cause a current. Since the earth is the reference for the signal any foreign earth current will superimpose on the signal. This is most common on unbalanced configureations. On balanced systems the earth is not the signal reference & with the use of differential input circuitry most induced noise is eliminated via common mode rejection techniques
  17. the toss

    rg59 max distance

    One of the most consistant problems I encounter with cat 5/6 installations. I am yet to see rodent damage to coax enough to cause problems. Of course where you are you may have "super" rodents
  18. the toss

    rg59 max distance

    The induced noise (hum) will be dependant on the EMR of the field surrounding the powered cable & this is dependant on the current in that cable. So for a cable supplying a 60W light globe you could run parallel for quite some distance with no ill effect while for a 415 v 200A welder circuit you would want it as far away as possible. The quality of your components (DVR , coax etc) also comes into play.
  19. the toss

    rg59 max distance

    There is no simple answer for this but the rule of thumb is 250m for RG59u. This is for pure copper , 95% braided shielding & 0.9mm centre conductor. But there are other things that may impact on that. The 1 vpp composite signal level is only a nominal level & not all cameras will have that output , some will be lower. A black/white composite signal will generally be around 4.7Mhz while a colour will be around 5.5Mhz. Thus the colour signal will have ever so slightly more attenuation. (not a lot but may be important over max runs - read on ) After the coax the most important item is the DVR I/P circuitry. All DVR inputs will have signal/noise discrimination circuitry. This is the bit that determines if bona fide video signal is present or if it is just noise. There is a threshold that if not reached the DVR will determine there is video loss and respond accordingly. This level is determined by the received sync level , the white signal level and the colour burst (chroma + luma ) level of the received composite signal. Generally it is accepted that with "quality cable" the following maximun distances are used- RG59u (7.9 db /m @ 50 Mhz) 250 m RG6u (4.9 db/m @ 50 Mhz) 350m RG11u (4.3 db/m @ 50 Mhz) 500m Keep in mind that the physical size of the cable increases as the performance increases & can be a problem in itself. For longer distances there are a number of techniques that can be used such as amplifiers , equalisers & compression devices if the buget allows for them.
  20. the toss

    Washed out night vision on new camera

    Check the LED mounting assembly. If it is not mounted squarely you will get internal transferance of the IR through the perspex dome. A bit like optical fibre transmission
  21. the toss

    Power wire splicing

    . Ditto. Or these: In a pinch, you can fill most splicing devices with gel yourself. Just go to any auto parts store and buy a tube of silicon dielectric grease. Often used for spark plug wires. They are not designed for stranded cable
  22. the toss

    Power wire splicing

    If I have to join then I AWAYS solder, sleeve then tape. However I do remember reading an article years ago that said if you strip 1/2" off both conductors , twist tightly then fold it over on itself it is as good if not better than any other mechanical jointing method.
  23. They do the job nicely as long as the cat 5 cable is not just swinging in the breeze. Baluns dangling off the end of cat 5 feature prominently in my worst nightmares
  24. Obviously cat 5/6 is the way to go to future-proof the installation. A Cat 5/6 install is good if done properly. I know they are out there but I am yet to see one. The problem is the fragile nature of solid core UTP cable. All the installations I have seen terminate the cat 5/6 pair to the balun which is then plugged onto the BNC DVR I/P. These are the jobs that you are not game to put your hand anywhere near the back of the DVR because you just know that something is going to stop working. If the installation is done along data cabling standards it should be fine. ie patch panel with feed through BNC connectors. Balun plugged into back of feed through BNC. Cat 5/6 pair terminated to balun behind patch panel. Cat 5/6 cable loomed & secured to prevent movement. Then it is simply a patch cable from the patch panel to the DVR. Easy & reliable but everyone is cost driven unfortunately
  25. the toss

    Suggestion for PIR/doppler sensor for trigging motion

    I don't know what PIRs you are looking at that recomend such a low mounting height Most PIRs that I work with want a height of about 2 - 2.5 m. There is an important reason to stick with the recommended mounting height & that is that it will give a known detection area for the design parameters. By knowing the detection area you can design a lot of "smart analytics" into the PIR. A sure sign of a poorly designed PIR is the inclusion of a sensitivity adjustment because the design parameters are so poorly addressed that it is left to the installer do whatever he can to make it work. Invariably the sensitivity adjustment is set too high to try to get maximun coverage which only results in false alarms. The poor old PIR is left with the decision - " am I seeing a human at 20" or is it an elephant at 80' " Generally in the PIR world the longer the designed detection range the higher the mounting height.
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