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Saturday, September 23 2017 @ 02:26 AM CDT

Location Considerations

Previous: Archive Video - Next: Overcoming Distances

If you're lucky, your live streaming wildlife critter will make its home near power and internet, away from public spaces and noisy aircraft or chain saws, and in a nice dry, temperate climate.

For the rest of us, location considerations will mean more than almost anything else in our quest for the next world-shaking live streaming camera. In this section we deal with what the problem might be for power, video transmission and internet.


Power

Next to the internet connection itself, power is the thing that most limits where you can put a camera and what kind of camera it might be.

“Shore or Mains Power” - meaning being able to plug directly into commercial power like you would in a home or office, is best of course because it is not a limiting factor. If you are blessed with the ability to run directly from mains power you’re likely set. See the section below on distances.

If you can’t plug into mains power then things get a bit interesting. The good thing is that there have been many advances in “off grid” power options in recent years. The bad thing is that most of them are pretty expensive.

We’ve used banks of batteries, replaced periodically with recharged ones. We’ve used solar cells, and we’ve used fuel cells. We have propane-powered generators. We’ve looked at wind power and we’ve looked at tide/current driven water power. See the next section on Overcoming Distance for details.

The biggest problem with power once you have it is ensuring you use it properly. If you are limited to your back yard or other fairly close subjects you will likely leave all the mains power items indoors and only run low-voltage to the camera/microphone position. This is best, especially if you don’t really know what you’re doing. 

Note: I am not an electrician. I make reference to and differentiate between “mains” and “low-voltage” power for a reason. In most places the legal cut off between the two is 50 volts. Anything below 50 volts does not normally need to be done by a licensed electrician (one of the reasons the telephone systems of the world use 48 volts as a standard supply voltage by the way). Anything above 50 volts must either be “temporary” through the use of certified products such as extension cables and break-out boxes, or must be done by a licensed electrician (or in some places the owner of the property) and conform to the local electrical code and be subject to inspection by local electrical inspectors. You MUST be aware of your local laws in this regard and follow the law! Regardless of the law, you should understand what you are doing, even for low-voltage items, and especially when using those temporary extension cords for full mains voltage.

If you must take power outdoors, ensure that you do it in a safe way, not only for yourself but for the critters and visitors.

Note: Always run outdoor power from a properly installed Ground Fault Interrupter (GFI) circuit!

The GFI guards against “leakage” of the power to ground by continuously monitoring the circuit to check that the amount of power going out on the hot lead is the same as coming back on the neutral. If there is any difference, the circuit is cut off immediately – fast enough that it is highly unlikely that the critter chewing on the cable or the small child with the end of the cable in its mouth would even feel a tingle. The point is that even with such a GFI protected circuit you should always ensure such things can’t happen anyway. The GFI may do a great job – but it should not be used to test whether you’ve waterproofed things properly; and when it trips, you should discover and fix the problem before you push the reset because a GFI in good condition, properly installed, will only trip if there is a reason.

Note also that a GFI will not guard against someone who is not otherwise grounded somehow. It won’t guard against things coming into contact with both hot and neutral – this still can cause a shock and death and is only guarded by the normal circuit breaker (separate or built-in to the GFI unit).

Power cables should not be just laying on the ground in most instances. Nor should they be strung in the air unless done properly, with strain-relief and at proper heights. Ordinary extension cable should not be buried.

All that having been said, for a typical seasonal or short-term installation a proper outdoor extension cord in good condition will probably do you just fine. The main thing to remember is to weather proof the point at which power supplies plug in and protect them from both the critters and local kids. I’ve used plastic pails and jars of all shapes and sizes to do this – simply putting the active end of the cable inside the pail with the open end down, and putting a large rock on it. Run the cable so that it does not cross paths or grassy areas where you’ll mow or walk. If you can, have an electrician run an underground feed to a plug-tower near the location you need the power, or if you have a garden border such as I have, to the border so you can run extension cords in the flower bed instead of over the grass. I have a pool-shed at the edge of my property with a separate GFI-protected circuit I use for all manner of things from the pond pump to cameras and lights. I’ve run extension cables at the edge of the flower beds all along the various areas to cameras, etc. and never had a problem with critters chewing on them – but then our cats have eliminated the rats and mice in the area.

At Goldstream park, Darren and Bob had to put power and other cables into conduit to keep the critters from chewing on them.

One last thing – there is a problem called “ground loop” that can cause problems when you plug something like a camera signal lead into a PC if the camera power is plugged into a different power receptacle from the one the PC is plugged into. I’ve had a camera here in my office die from this because I have more than one circuit and forgot to check where I had plugged each item in.

A ground loop typically only happens when one or both circuits has a heavy load on it. Here in my office I have several computers on the one circuit (specially installed just for them) and the other one is shared with some lights and our kitchen’s microwave oven (it’s an old house – this is not likely in a newer home). I had inadvertently plugged the camera into the shared circuit. The heavy current draw on a circuit (the microwave on one and several large computers on the other) can cause a difference in voltage between the ground on the two circuits. It shouldn’t, but sometimes it does. This can cause current flow in the ground on the video (or audio) connector between the two devices, and can heat up and blow out the tiny components that normally deal no such current at all.

There really is little you can do about this if it happens, except be aware that it could. This cost me about $200 to fix the camera and I scratched my head for a bit before I realized what likely had caused this otherwise very reliable camera to fail in this way – the technician said that some of the parts looked like they had slowly cooked and he’d never seen anything like it. If you have a volt meter and know how to use it, you might measure the voltage between a camera lead and the unit you’re going to plug it into before you actually plug it in. I did this and measured almost 5 volts (AC) when the microwave oven was turned on. The components usually deal with less than 1 volt on these signal (composite video and line audio) lines and nothing on the ground – so 5 times the voltage was what did it. This 5 volts is less than 5% of the 110 volts on the circuit – but it is on the ground, where there should have been no voltage at all.

This is why many older computer installations used what are called “isolated ground” circuits for their computers. These can usually be told from normal wall plugs by the fact that the outlets are orange instead of the typical white or brown. These circuits are set up in such a fashion that there is no possibility of ground-loops or voltage differences between grounds on different circuit. The problem was much more prevalent in the past before the advent of transfomerless power supplies like the typical PC and “wall wart” units we see today – but it is still possible.

Video Transmission: Coaxial Cable, Twisted Pair, Fiber or Radio

There are a couple of ways to get video (and audio) from composite video cameras without putting an encoder in the field. These involve extending the typically 2-300 foot (100 meter) limits of coaxial cable by converting the signals in some fashion.

It is possible to send power to a camera and receive video and audio back from it through a single piece of coaxial cable using something like the VDS-2200 cable balun. This system injects up to 24 volts at the “receiving” end, and provides 12 volts at the sending end to power a camera – and in turn takes the video from the camera and audio from a microphone and passes it back to the receiver. We’ve used this over a distance of 1000’ at our Sidney nest site for several years, with a cable each for two cameras.

It is possible to do the same thing over twisted-pair (like Ethernet cable) but for shorter distances.

It is also possible to send the signals over fiber-optic cable, but there is no power facility in this case.

At the receiving end the video (and audio) must be connected to a standard video capture device, just as it would be if the camera were directly wired to it.

Internet

If your camera is IP capable then you need to get the internet to it. Indoors this may be as simple as running an extension cable from your firewall/router, or using a wireless camera and access-point setup.

The typical Ethernet extension cable is not designed for use outdoors. I have seen some that stood up to a year or two of weather, but that’s not what they’re designed for.

For use outdoors, you will typically need to purchase bulk cable and put your own ends on it. The cable is designed for one of two types of outdoor use: direct bury, or aerial. Both of these use the same (typically black) plastic cover with UV and waterproofing (gel filled interior) but the aerial will have a steel guy-wire molded onto it as well, used to hang the cable from poles and carry the weight.

If you have WiFi and the IP camera you choose has it built-in, then for urban yards the WiFi access point you got with your ISP’s modem, or one purchased for use with your laptop, will likely also work for the camera. There are two potential issues:

  • distance and interference
  • total throughput of the WiFi system

If you find your camera only works marginally, or doesn’t work at all on the WiFi, then you may want to move the access-point for better coverage. It may be necessary to install a second, dedicated access-point (AP). This is especially needed if you use your main WiFi link for a lot of other traffic, like to a server on your LAN. The second AP should be wired up directly to the main firewall/router, and placed closer to the camera. The second unit should be set on a different channel from the main WiFi access point and may even have a directional antenna put on it. There are industrial units that, while a bit more expensive than the consumer ones, are very easy to use for distances up to miles, and have built-in directional antennas.

It is also possible to use a WiFi range extender. This is a stand-alone unit that both sends and receives WiFi – some units do both at the same time using two radios, some “ping-pong” style where they receive a packet on one channel, then send it back out on the other one immediately after. The dual-radio units are best for the streams from a camera. Test the single-radio ones in your situation before you settle on one.

See the section on Distant Internet for distances outside the urban backyard.

Tag: wifi access point wifi extender power low voltage ethernet twisted pair poe antenna battery generator

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