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Old August 1st, 2004, 01:00 AM   #16
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So is there anythign available for someone who needs to transmit live video from a DVX100 to the director's chair/monitoring area?
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Old August 1st, 2004, 05:24 AM   #17
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the only difference between a good and a bad wireless transmission system are the antennas and the way you positionned them.
if you choose very short frequency (1 Ghz and above) you can almost consider that you have a point to point link that requires pointing the antennas each together.
That is why for mobile stuff, 800 Mhz system are more failsafe, but unfortunately they just are in the mobile phone range and that is pretty bad.
the 1.2 Ghz is nice, but devices are hard to find since the 2.4Hgz and 5ghz start to be more popular frequency (and crowded too).
To position your antennas, you need somebody who knows a bit about that and even worse you could need people to operate them , especially if the emitter or receiver are moving a lot.
Usually a good set of antenna (15db gain) cost as much as the electronic attached to it. There is some diversity receiver that allows you to put 2 or 4 antennas to make sure the signal is never lost, but this costs the hell.
A good start would be to install some parabolic or yagi antennas at the receiver, located at an elevated point (roof or mast).
Use antenna amplifier on the antennas, since 10 feets of average quality coax can gobble up the few dB gained by the antenna.
Try to put the receiver very close the antenna since it is easier to handle video signal than uhf signal on long cables.
Again this is a work for somebody who knows about radiofrequency propagation.
http://www.fab-corp.com/ is a real specialist for antennas, cheap and fast.
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Old August 1st, 2004, 01:47 PM   #18
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Nick, if you are looking for pure monitoring as opposed to "broadcast quality" transmission, try looking at www.supercircuits.com. They have a number of inexpensive transmitters of different stripes. Size-wise, the 434 mhz transmitters are well-suited for DV cameras and can be received on any slide-rule type TV tuner (like a pocket TV); they also sell tuners for this frequency. All RF transmitters are prone to interference but for sending an image to the director, this may well do it for you.
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Old August 1st, 2004, 05:48 PM   #19
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Hi Charles, thanks.

Since I have a field/production monitor, I wanted to see if I could hook it up to the DVX100 somehow without having to run cables. I was also hoping that the quality of the video would be good enough so I can frame the shot PLUS check on lighting.

However, I can probably get by with just getting a nice B/W image so I can frame the shot.

What do you think?
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Old August 1st, 2004, 09:02 PM   #20
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Hi Nick,

You can certainly receive a color signal from a cheap transmitter, but you can't trust it for contrast values. You will see plenty of luma and chroma shifts as the camera moves around. So yes, its useful for framing, but I wouldn't trust it for lighting. Better to have a length of BNC available and run it to the camera during rehearsals to work out the lighting on the monitor, then switch over to the transmitter for the shot itself.

Going to a broadcast microwave system would be required to truly trust the image, and this would likely be too expensive to make sense.
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Old August 1st, 2004, 11:43 PM   #21
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<<<-- Originally posted by Charles Papert : Hi Nick,

Better to have a length of BNC available and run it to the camera during rehearsals to work out the lighting on the monitor, then switch over to the transmitter for the shot itself.
-->>>

I think you just nailed it. I'll do it that way. Thanks!
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