percy

Labor is one of the most difficult items to estimate. Before I got into this business I was a senior manager for a large software company. I was responsible for major project running into the millions of dollars. I had to estimate labor cost for projects that could run for months with vague requirements. I used statistics to estimate my cost and we made money on almost every project. The ones we were over on were never more than 10% over or estimate. The math is not that hard. 1. First I developed three estimates for my labor cost. A.is the best case. B. the most likely time and C. the worst case. 2. Next to get my initial estimate I take .2 x best + .6 x likely + .2 x worst So if my estimates were 4 hours best case, 7 hours likely and 12 hours worst, my initial estimate would be .2*4+.6*7+.2*12 = 7.4 Now this is not your estimate, for those of had statistics you will remember the bell curve. The estimate of 7.4 hours only gives you a 50/50 chance of being right. Next we find an approximation for the standard deviation which would be the difference of the extremes multiplied by their probability; sd = (worst case) x (probability of worst case) - (best case) x (probability of best case) sd = .2*12 - .2*4 = 1.6 Using normal distribution tables; +/- one standard deviation 68% confidence interval +/- two standard deviation 95% confidence interval +/- three standard deviation 99% confidence interval. So what does all this mean. If we take two times the standard deviation or in our case 1.6 * 2 = 3.2 and add it to our initial estimate of 7.4 which gives us 10.6 hours we can say with a 95% chance that our labor hours will be less than 10.6 hours. This works, you don't stay in your job long losing money on million dollar projects.

I've used Seco-Larm Enforcer Day/Night Camera with some success. They see about 80' in the dark. The only problem with IR is you it has to hit a target to reflect back to the camera. Depends on the location, lighting, lens and distance you can get a washed out look on your camera at night. I tried a new camera Speco Technologies HT-7246IHR color intensifier camera. It does not have IR but uses electronics to enhance the visible light. These things are great, makes it look like daylight. First time I used one I passed the monitor about 9:00 PM and thought the camera picture had somehow frozen during the day is was so bright. That was until I saw the dog get up and walk across the yard. I looked out the window and it was dark. I now have two of these replacing IR cameras.

I just added a backup camera to our work van. It's a Chevy Express Cargo Van and you can't see a thing behind it. I took a small color bullet camera attached it under the rear bumper and ran some RG59 w 18g power to the cab. I spliced the power wire to the cigarette converter on a small 4" color monitor. Plugged it into the cigarette lighter and I had a back up camera. If you want it to come on only when you back up to have to attached the power to the backup light so you only get power when in reverse. I like having it one while driving, you would be surprised at the number of time some small car comes up right on your bumper and you can't see then out you side mirrors. .

Has anyone used a PTZ camera over wireless. I have a client who wants a camera at the back gate (it's a large condo complex, about 1/4 mile from gate to office.) and he wants PTZ cameras. We planed to use wireless until the client through in the request for PTZ. Is it possible to get anything other than video and audio over wireless?

We just finished installing nine cameras in a strip mall. We used RG59, with 18 gauge wire and 12V power supply box. All our camera runs were over 400' with one run being 700' and we had no problem using 12VDC voltage on any of the cameras. But to be on the safe side I had cameras the would take both 12VDC or 24VAC and a dual voltage power distribution box.