Have a uniden UWG900 system where one camera has a blurry dark strip in the received picture. Have cleaned camera lense but no difference. Any ideas?

There are two possible problems:

1. The camera is defective.
2. Operator error.

In most cases, #2 is the answer. Digital cameras are convenient, but are sensitive. They have very bright flash units and often wash out the picture that you are trying to take, especially if the item is reflective, you are close to it, and taking the shot straight on. Thus, many users turn the flash off to get the picture to look better. Now the camera has to work differently. In order to get the right amount of light to get a good picture, it will slow down the shutter response. This lets more light onto the CCD and results in a brighter picture without the flash. BUT, the slower speed means that you must be very still in order to prevent blurring, and many users cannot get the hang of it. Also, some cameras do not adjust well to lower light and thus are not only blurry, but dark as well. Try shooting different scenes, indoor as well as outdoor, short, mid and long range in different lighting conditions. If everything is dark and blurry, regardless of the situation, then as a last resort, have another person try to take a few shots. If they are no better at it, then blame the camera. Otherwise, just practice with it until you get good at it. Some cameras are more user-friendly than others.

What make and model camera? Which Sigma lens? Do you have autofocus turned on, both on the camera and the lens?

There are several possible causes for blurry pictures.
1) Camera motion. If everything is blurry, it's most likely because the camera moved while the picture was being taken. Make sure your shutter speed is fast enough if you're handholding the camera (longer lenses require faster shutter speed). Alternatively, put your camera on a stable surface, such as a tripod or a tabletop.
2) Subject motion. If the subject is blurry but the background is sharper, then the subject may have moved while the picture was being taken. Use a faster shutter speed. Raise the ISO if needed. There are limits, of course. If you're trying to photograph a fast-moving object in the dark, you probably won't be able to.
3) Improper focus. If the subject is blurry but something else in the picture is sharp, then the camera probably focused on the wrong object. Move the focus selector to the subject you want in focus. Alternatively, center the viewfinder on the subject, press the shutter button halfway to lock focus, then reframe and shoot.
Without any more specific information as to what and how your pictures are blurry, I'm afraid the above is all I can give you.

Blue CRT has bad cooling fluid or is bad. Or you moved the lens focus adjutment by rotating top of lenses.

Yes, if you have used different lenses and a smudge still appears (in the same place) there may be something on your sensor. Have you cleaned or touched the sensor in the past? Typically sensors only get dust (shows up as small fuzzy dark spots) on the sensor, not smudges.

The camera is most likely a nikon... but the model may make a difference.

Possible internal damage in the gearing.

Possible also to try to reset the camera settings, that may or may not help in this case.

That would explain the darkness if the lens is stopped down. It would seem the aperture control is faulty on the camera body. Normally, the aperture remains open until you take the picture. It is only closed down while the shutter is open.

your machine most likely has toner spills in it.
if you send faxes face side down follow these instructions ;
1- take out toner
2- look for thin glass strip on bottom inside the machine
3-wipe clean

if you make copies side up then do the same except look for glass strip on the upper side of machine

First try to take photo in a sunlight, if the photo is still hazy then clean the lense and make sure you dont put your finter anywhere in front of the camera.

If the photo is still hazy then it could in internal camera fault.

If the photo is fine in the sun but its blurry in the dark then take photo with flash if thats ok then you just need more lighting.

Also make sure the ISO Rating is auto or 100 many people set ISO to 800 and then forget about it. It causes hazy photos in the dark

Contact Customer Support this is possibly a CCD problem- they may still fix it.