wishmegood

Hi all, I have a big doubt on 'pc-based DVR vs standalone DVR'. I had commissioned a cctv system recently, which includes 16 units of 1/3" Sony Colour Dome Camera, 420TVL and a pc-based Geovision Card, GV800. While testing all these camera with a television, they could display clearly. Yet, while I connected them to the GV800, the resolution obviously decreased; somehow, even I connected only one camera to this 16-channel Geovision DVR card with less than 1 meter of Belden RG59 coaxial cable between DVR and PC, the image quality is still much poorer than the condition I connect the same camera directly to a television. What could be explained about this? I didn't know how to explain to the customer that I showed them the camera could display clearly before we started the installation, but now the image quality is bad! I had configured the settings inside the GV800 to be the best for monitoring and recording already. Is it possible that, Geovision couldn't give enough resolution up to 420TVL while using the aforesaid 1/3" Sony Colour Dome Camera, 420TVL? If so, with this condition, I change all the cameras to be 1/3" Sony Colour Dome Camera, 520TVL, the image quality could increase a bit, but not up to 520TVL too, right? Is there any other better solution, other than using GV800 / GV900? Will a 16-Channel Standalone DVR, pentaplex will give better result? Thank you very much for your advices!

Hi, does anybody has problem on Avtech 760 with Hitachi hard drive? The problem now is we use Hitachi hard drive 7200rpm/8M 250GB for AVC760, but on the TV screen shows only 30.741GB for hard disk capacity, no matter how we formatted the hard disk using AVC760, the capacity was still the same. And the recorded data could only be traced back for two days, no recorded data was older than 3 days. Does anyone has idea how set the jumper for the Hitachi hard drive for 16/32 cylinders? Moreover, upgrading firmware will be helpful? Any help will be very much appreciated.

Daryl733, thanks so much, I had solved the problem, it's hdd jumper setting problem, now the DVR could detect 227 GB, and it is considered normal. Cheers!

Here i am again. I faced a problem recently that a DVR always 'skip frame' while recording under motion detection mode. I take an example to explain the 'skip frame' here. Say, I have a camera at 1st floor, called CamA, and another camera at ground floor, called CamB. While a person walking down to ground floor from the 1st floor (within coverage of camera monitoring), the DVR should record motion for CamA first, and then record that for CamB while that person reach ground floor. But now the problem is, from the record playback, we could only see the recording for ground floor from CamB, no recording from CamA. Conditions: CamA works perfectly always, it can record every movement always, but only sometimes it doesn't work which bothers me indeed. Could this problem probably come from firmware inside the DVR? Could someone please correct and clarify me with this issue? Thanks so much.

scorpion, thanks for your valuable info. Yet I still couldn't be able to find out the brand name, nor the supplier could give the brand name, it's OEM products they explained. this is my cctv business. I set all the sensitivity to be highest level. Recently the customer complained again that one of the camera kept recording for the whole night while dvr was set to motion detection mode, and it turned to normal operation the second day. This confused me much, thus i decided to change to a brand new unit of dvr, AVTech for them. Now the problem should not appear anymore. Thanks again for your good knowledge.

The DVR i am using is without brand name, and it is said to be manufactured in Korea. It is considered a medium-end and low cost DVR.

Grace, thanks so much for your info. did you mean the contrast affecting the sensitivity of motion detection? in fact the camera recording was carried out inside a premise, and the problem of 'skipping frames' occurs once to twice in a day sometimes. i guess the sensitivity of motion detection itself isn't the cause for this problem, as sometimes the DVR even can record a sudden light from outside the house during early morning, say 4am. is it possible the issue coming from the firmware inside the DVR too? on the other hand, do you have any advices on the 'frame freezing' problem? it could be explained as this: a person walked to Point A within the camera coverage area, the recording suddenly freezed for seconds, and from the following recording it also did not show how that person left the Point A. so basically is it also possible problem coming from medium-end DVR itself? any additional advices will be very much appreciated. Thanks so much.

First of all, thanks so much for the reply. The sensitivity for motion detection has been set to be the highest, and it works well most of the time while we perform testing purposely and during normal recording, yet from record while we play back, sometimes it skips frames that should be recorded, and we also found sometimes some frames just suddenly freeze for seconds, is it possible the problems coming from hard drive (the brand for hard drive we use is Western Digital) too? I heard somebody said this DOES matter, cause Western Digital hard drive cause issues frequently? any other inputs will be very much appreciated. Thank you.

Thank you so much that I've received the valuable info

Hi, I'm kinda new to DVRs. Could someone please clarify me whether the DVRs from Avtech & CPcam are the same? say, AVC760 & CPD560, are they completely same? As the websites for them are different, www.avtech.com.tw is for Avtech, while www.cpcamcctv.com, their company contact details are not same too. Thanks for any help.

Hi all, does anyone know where to download the oder version softwares for Geovision, from version 6.0 to 7.x, they are not the upgradable versions, but the original program? Thanks in advance!

you need to type in the format as follow at client's computer IE browser: http://192.168.1.xx:80, where xx is the last digits for your client's IP that you wish to view through LAN, and the port is the one you set inside the GeoVision software, the default is 80. On the Geovision host's pc, you need to run web server, that's all you need to do. Hope this helps.

Hi, would someone please recommend me which one of RG59 coaxial cable that is more economical, and yet the quality is good enough for normal short to middle range of running? Meanwhile which one of RG6 is recommended to use for these conditions? As I have had one that is few % braid with aluminium and its core is made of aluminium too, but performance is not satisfied. Anyone recommends to use Eurostar RG59 from Taiwan, or Commscope RG59 from USA? Thanks for guiding.

Well, could someone please tell me what is bare copper conductor? Is it a pure solid copper conductor? And how thick is copper covered on steel conductor for CCS normally? Thank you again, I am in a big doubt on these conductors.

Hi all, from the article below: http://stamhost.com/aloa/article_video_signal.htm, and based on the knowledge linked as follow: http://www.anixter.com/AXECOM/AXEDocLib.nsf/(UnID)/50D0B4C23C7D301286256F5E006048EB/$file/coax_101.pdf#search=%22coax_101%22 could we conclude that the video signal actually run the outter side of core of a coaxial cable? Thus, we actually need a coaxial cable that is with CCS for core is sufficient for CCTV system? And percentage of braid coverage is helpful on reducing noises from environment only? Thanks.

Thomas, thanks for the suggestion. Kelvin, thanks for the valueble info. Now here comes with another problem, why the price for RG59 with spec of 0.81mm CCS (80% braid coverage) is more expensive than RG59 with spec of 0.81mm Bare Copper (80% braid coverage)? Thanks again for guiding.

Thanks Kelvin. Is MK-4 a brand for the cable? It is originated from which country? Do you know where is the website for this cable? Thanks again for guidings.

Thanks for the recommendation. How do you do think about Commscope RG59 cable? Anyone ever used it? Thanks again.

Thanks for output. It seems Belden 9104 RG59 suit with this spec, besides Belden, I meant do you have other brands that you might recommend? As the price for Belden is expensive... Thanks again.

Can RG 6 coaxial cable be used for short run, about 20 to 25 metres, on CCTV system? Why the price for RG 6 is cheaper than RG59/U while the former can be used for further distance up to 1000 ft, and the latter could only be used up to 750 ft? Some said the min. distance of a coaxial cable must be 2 inch away from a power cable, is this true for all the conditions if crossing coaxial cable and power cable at 90 deg.? Thanks for outputs.

Thanks, it's a very good answer that I wanted. I am lucky to learn much from here. Thanks again for good knowledge.

Dear all, I am quite new to cctv, there are some problems annoying me these days: 1. How to choose the cctv signal cables by inspecting their specs, like max. attenuation (dB/100ft), besides choosing the well-known Belden RG59 9104 cable? 2. How much the frequency normally the cameras use? this is used to inspect how much the attenuation will have from cctv signal cables for long run. 3. How many amperes of current from mains cable will significantly interfere the camera signal? Will the cables for house-use socket (13A) interfere the camera signal significantly? Is there good way to reduce interference if being not able to avoid camera signal cable going nearby to mains cable? Thank you so much for any outputs!

Thank you for the explanations.

Could someone please clarify me what are dry and wet contacts used in GV-Net/IO Card. Any outputs will be very much appreciated.