normicgander

You can measure the DC loop resistance and obtain a fairly close measurement of the cable length. But, it's really the line capacitance which acts as a low-pass filter which impacts picture detail (not that excessive, "D1" DVR video compression won't finish the job ). It is frequency dependent and is why the higher frequencies roll-off significantly over distance. Equalization is important and more and more I'm finding that ground isolation of the CAT5 line necessary. [/img]

Hmm..Is there such a thing in video which makes applying compression realistic or worthwhile in the first place?

I did find this link showing the DOM as part of a kit... http://www.avermedia.com/images/www.avermedia.com_EN/nv6480dom.pdf

True, but given that AverMedia sells pre-built DVRs like the SA6416/SA7208H plus various capture cards for the dealers or others who build DVRs, that is why I thought they might offer the DOM also. I placed a call to them to see.

Thanks Rory! I guess there's a difference between the XP embedded and the regular version of XP Pro. If I recall correctly, awhile back you had posts on discussing the modification of the software in order to made the dvr more stable. That's beyond my gray-matter... In general in like the idea of building your own PC based dvr. I think this may allow the dealer to provide faster service of failed units.

I think the term is Disk On Module if I recall. Aver installs them in their SA6416 and SA7208H pre-bulit DVRS. I'm not sure if Avermedia sells the DOM loaded with their XP and DVR software. Far from being a software expert, I'm interested what OS is being used in custom PC based DVRs. Many seem too use a cut-down (customized) XP Pro. Any ideas Rory? Thanks

VST_man, very good question, for which I'm interested in as well. But want due you use for an OS? Avermedia uses/offers a cut down version of XP Pro on a DOM.

I have to agree. The cost, application and what the customer is willing to pay seems to ultimately drive the final solution. Scorpion is correct in my experience- residential installs can be high maintenance and a stand-alone embedded or OEM built PC based DVR is the way to go (IMO). Avermedia makes a good DVR, but they need to have individual FPS record settings for the SA6416, EB1304Net and EB1704H units!

Surtech is right on. But I will say this has been a serious problem in our industry since DVRs were introduced. Most DVR manufacturers have a DI or 720 x 480 record setting, along with low, normal, high, superfine modes to name a few. Even in 720 x 480 with superfine setting, the DVR will never have the same resolution of the CCTV camera. A 720 x 480 camera with a measured horizontal resolution of 480TVL (which has meaning) which is recorded on a DVR in it's highest quality setting will not be faithfully recorded at 480TVL. It will be reduced by a factor of the applied compression. I realize we need to have compression, but I wish OEMs would provide TVL resolution instead of "720 x 480", which can mean nothing or very little. This why we need an industry measurement standard for DVRs.

My understanding of the poll is that it's for an OEM which provides the best overall quality product line. That being said, I purchase KT&C cameras routinely, but Panasonic's overall quality of construction is better than most IMO. However, KT&C produces cams which Panasonic or others do not. I think it would be hard to use just one OEM in general...

I have used video baluns with mixed results. I have to agree with Rory, in that I will always try to install RG59 if possible. Video baluns are viable solutions for many installations, especially in cases where there is a need to reduce cable density. I think the term balun in somewhat of issue. By definition, a balun should isolate the unbalanced circuit from the balanced side. Have you ever checked to see if you have continuity between the ground/shield of the BNC side and the (-) terminal of the UTP side? You will get continuity, meaning there is no isolation and perhaps no balancing. How can you have in and out of phase signals? I'm still researching this however, and at this point I'm believe the baluns are some kind of an autoformer configuration. I do think the "baluns" perform an important function in impedance matching the 75 ohm source (camera) to 110 ohm UTP line impedance. Generally, I have noticed more high frequency loss with UTP baluns. I have inserted NTSC multiburst signals into serveral different systems and the loss ( about 6dB @ 4Mhz) at 300 ft is considerable, if not ugly. Active receivers for greater distances for proper equalization is important. Note- Yesterday I did see a passive video balun from a company which stated it had built in "ground" isolation.

Scruit- check out VAC. Used them a number of years ago. http://www.vac-brick.com/ Unrelated but I saw a video tester which some folks may wish to look at: VT-1.

Can't wait to vote-again

Rory, Good idea- if Ubon94 is good with it then let it rip. But should the "best" be based on the company's overall quality of their camera product line, service and support? Perhaps I'm making it complicated.

It's a good poll question. Keep it simple- the best (quality I assume) overall manufacturer. CCTV_down_under listed some good ones. How can the rest be added?

Surtec, you make some great points. Licensing without enforcement is just about collecting fees. But, enforcement will add significant costs to each project. Applying common sense, If I cheat even one customer or hack a series of installations, then the word gets out or I could be haulded into small claims court for lack of contractural performance. Most of my customers ask for references and ask me about similar projects proposed.

Anyone evaluate these cameras yet? Provideo WDR-D3 wdr dome Provideo WDR-T6 wdr box camera

Ever see that Canadian show Holmes on Homes? Everyone of those hack jobs was done by licensed contractor. Maybe next someone or lobby will propose that you have a license and a college degree in BSEET or EE or something.

But if the system is not fully functional and profitable they will go out of business at some point. Then you can R&R the system gain a new customer. Still, most anyone even remotely serious about starting a CCTV business can pass a multiple choice exam from the state. Most states have hungry bureaucracies to feed. In fact, an industry magazine I read the other day had ads for companies who specialize in state exam preparation (most likely former state employees). However, as an industry, this is a good topic for discussion. I believe in the free-market and I don’t need to license number, especially here locally, to be better or more qualified than another company. Beyond licensing however, I think the costs of local LV electrical and electronics job permits which will have a more detrimental impact on our industry- especially for the small projects.

I thought there was a question asking who makes the best camera, but maybe it's freudian on my part

KT&C and Hitachi should be on the list

Moe-FYI

able1, What's the status of your moisture problem?

The bureaurats here in Michigan, some high voltage types (CL1), large security and other LV companies have tried or supported the implementation of licensing and LV job permits. Thankfully it has failed. The number of lobby groups however is amazing. Licensing and certification(s) never guarantees quality service and support. Plenty of other industry examples. Word of mouth and legal action helps protects the consumer. Reputation is everything....

The cable (either UTP or coaxial cable) connected from the camera to the DVR or monitor is a power matched transmission line. The input and output impedances are 75 ohms. If you "T" split the line and connect it to separate 75 ohm inputs, you will have a double termination. This condition will cause half (6dB) or 50IRE of the video signal to be lost. This is not good for the A to D conversion in many DVRs, where the inputs are full-scale (Fs) calibrated to 1vpp or 100IRE. You may lose half your dynamic range. Surtech is correct- use a DA if no loop thru is available.