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wisp_engineer

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Posts posted by wisp_engineer

  1. Posted

    Sounds good. You'll need to identify it as to what gender the SMA is.

     

     

    Here is a small panel antenna that might work for you. This one has an RP-SMA on the jumper:

    http://www.hyperlinktech.com/item.aspx?id=1819

     

    And here is one with an SMA on it....

     

    http://www.hyperlinktech.com/item.aspx?id=1823

     

     

     

    There are also a variety of yagi antennas available:

     

    http://www.hyperlinktech.com/familylist.aspx?id=149

     

     

    Are these cameras outdoors on a pole or inside a building?

  5. Posted

    Having two different RF links means you need to have each link on its own channel. There are 11 channels available in the unlicensed spectrum here in the USA.

     

    There are only 3 useable channels: 1 6 and 11

     

    You can however use a combination of 11 channels, like 2 and 7 or 3 and 8, or 10 and 2, etc etc. You need 4 channels of separation in the middle, to really ensure you do not run into interference problems.

     

     

    Keep in mind that there are other 2.4GHz products out there so you are contending with those as well.

     

     

    Having rubber duck antennas on your transmitters puts another nail in your coffin, as you not only hear the transmitter on the other end that you are supposed to hear, but every other 2.4GHz transmitter and device in that frequency range as well. This is why I advocate (and engineer my own jobs) using sector antennas and high-gain directional antennas like yagi's, panels, and dishes.

     

     

     

    So.... Step one: see which channels you are on and try and change them around, but make sure you have adequate spacing between them.

     

    Step two: Try and see if you can do a spectrum analysis in your area to see what other devices are in operation and on what frequency. Doing this may help you in deciding what channels to pick for your equipment.

     

    Step three: If one and two does not help, try a more directional antenna on each radio. Maybe start out with a low-gain yagi, perhaps maybe a 9dB or 12dB model on both ends. You can also change the polarization of the antenna so it runs horizontally. This helps in that most sources of interference (like 2.4GHz routers and what not) are vertically polarized. You will get 25dB or so of isolation doing this. It will help out immensely if you are experiencing interference to do this.

     

     

     

    Come back for more questions/answers if one and two do not work out, as there is a bit more planning involved to do step three.

  7. Posted

    I am confused I have 30 in the field right now with no problems. My customers are very happy with this product. I tested them in our office for 1 month before putting any in the field. I have no problem seeing the grass in the yard as green in little light (moon light) I see cats walking around the building in real time not delayed or frozen. I am not sure where you bought your cameras from but I do not have the same probems you are listing here.

     

     

     

    Can you post some pics? Perhaps a capture of someone walking in low light?

  10. Posted

    Thanks for the reply.

     

    Well my thought of fiber was that it would protect the equipment from any surges induced through the line. I am planning on putting a surge protector from Ditek either at the head end or the camera and bonding that back to their electrical grounding system. Hopefully this will protect it.

     

     

    I looked into some passive baluns and cat5 but by the time you totaled those items up, it was more than just running the coax. All indications are that this customer is not interested in adding additional cameras at the location.

  11. Posted

    I am working on a 2-camera system. The coaxial run must go from the main building where the DVR is located to across the parking lot to their warehouse/shop where a pair of fixed cameras will be located.

     

    First, I guesstimate this run around 350-400 feet. RG-59 should be good enough without having to add any amplifiers on the line is that correct? My understanding is that you can go 750-feet on 59 before you run into problems.

     

    Second, since this run is across the lot between two buildings I am concerned about a difference in voltage potential which could cause damage to the equipment should static build up. I would normally think one would put in fiber as the transport for the video feed from camera to DVR but the ADI guys say coax is fine. I am having them add in a surge supressor per camera. Should I put this at the camera end or at the DVR end? Normally NEC requires protection at the building entrance but that'd be odd to do I think.

     

    Thoughts or suggestions?

  12. Posted

    Sorry to hear about the losses.

     

     

    Being in the communications business primarily we spend countless dollars on our own infrastructure to attempt to protect it the best we can. There have been times that there were direct strikes, and nothing was damaged and then there are times where there are direct strikes and the breaker panel is thrown off the wall, equipment is blown to pieces, etc. Lightning is a quirky animal and you can only do your best to make sure EVERYTHING is bonded and then grounded so that it is all at the same potential. In theory, electronic devices could get struck by lightning and make it out unscathed, but only if EVERY component is at a common potential to earth and capable of dealing with the voltages induced during the strike.

  14. Posted

    I figured you'd be LOL'ing haha

     

     

    I came across the relationship between HW and ADI

     

     

    I thought it was funny considering that both locally and over the phone, they heavily push Speco.

     

     

    Do you have any objections to Honeywell product? It was a toss-up between HW, Samsung and Sanyo.

  15. Posted

    I found an IP rating explanation over on Honeywell's site today but it wont allow me to link to it. I'll have to download the PDF and host it on my FTP site.

     

    IP67 is as follows

     

    6 signifies Protection against dust tight (no dust allowance inside enclosure).

    7 signifies Protection against temporary immersion (30 minutes under 1m of water)

     

    I think 67 is ok for outside use, but someone can verify. I am still too new to this whole thing.

  18. Posted

    Thanks for all the input. This has turned out to be a great discussion.

     

     

    I've scrapped the Speco product and instead am going with some Honeywell fixed domes. They feature .03Lux levels and have interchangeable lenses. My only concern now is the 480TVL's instead of 540TVL's, but the guy at ADI is assuring me that the 480TVL's on a Honeywell camera is very very good 480TVL's... he said it rivals other makers 540's.

  19. Posted

    Ok, so if the images are bad at dusk and no light, what about inside the cooler during operational hours where it has some light. This place isnt totally dark its just dimly lit like any other big freezer.

  20. Posted

    Wow then this product is definately not for this customer.

     

     

    They need something that works better as they are trying to pin down some inventory losses in the cold storage area.

     

     

     

    Anyone have any suggestions?

  21. Posted

    So I am working on engineering a 5 camera system for a large cold storage area. This will be my first cold storage job so I am really lost. I looked at some of the cameras from Slientwitness here that you all have raved about but the price tag is a bit high and while they are good I think it might spook the customer.

     

     

    I called ADI system engineers and explained what I need: varifocal lenses, cold environment operation, and something that can work in the lower light levels of a cold storage cooler facility. The customer also requested that whatever cameras we pick, deliver clear and sharp images. ADI suggested I use the Speco Intensifier series.... This particular model:

    http://207.56.187.246/cart/products/productDetails.asp?prodID=942

     

     

    Does anyone have experience with these? I have seen mixed feelings here about Speco products so I am really hesitant to offer these but the guy at system design said they are quality. I suspect they get a large kickback from Speco though, as everyone there raves about their products.... Hmmm

     

     

    He also suggested a DVR from Speco.... Not sure on that one.

     

     

    Suggestions or comments?

  22. Posted

    I would put the punch block at the NVR side.

     

    Put your cameras in, run the CAT cable through conduit down to the punch block. Punch them in, and then run patch cords to the switch. Patch your NVR into the switch and you are set.

     

     

    This would be the best way of doing it. You always want the network switch or "head end" in this case, connected via patch cord to punch block. This ensures if you have to make a cabling change in the machine room you just move patch cords around or buy longer or shorter ones. The cameras will be static in that they will probably never be moved around.

     

     

     

     

    EDIT: I just re-read your post. I'll leave the above info there, but expand a bit.

     

    I take it you want to run just one cable down to the NVR from the attic. If that is the case you will need to answer the following questions:

     

    Is there commercial power in the attic?

     

    Is this attic climate controlled (HVAC regulated environment)?

     

    I suspect you are thinking you want to add a device to split one connection into multiple connections. Is this correct? If so you need an active device such as a network switch located up in the attic area to "split" the single network connection you will bring up from the NVR.

  23. Posted

    Interesting product... I see a lot of big telecom rooms in major buildings where I am at that the firestopping has been broken out and cables pushed in. I suspect the companies IT staff did this as any respectable contractor wouldn't (at least ones that would do work in these types of places).

  25. Posted

    Well the tree might offer the lowest potential so it may bear the brunt but with lightning you have to also remember there are after-effects like residual electrical discharge and resonance that must be dealt with.

     

     

    Ever see a communications tower grounding system? They have the halo at odd path lengths and bonded certain ways for a reason. Those odd/even lengths average out to produce a grounding system that ensures that after the strike the left over energy is dissipated properly without causing damage to sensitive equipment.

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