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150" tv (1 Viewer)

Neil Joseph

Senior HTF Member
Joined
Jan 16, 1998
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8,332
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Neil Joseph
I have seen this reviewed a few times and the results were always very negative.
 

Ottis Fletcher

Stunt Coordinator
Joined
May 16, 2002
Messages
122
Crap, I use to have link to a site that gave the directions for free. I also read reviews and they were all terrible.
 

DeepakJR

Second Unit
Joined
Mar 10, 2002
Messages
255
Real Name
Deepak
I actually bought this stuff a few years back. But for $9.95 i cant complain. The results were very bad indeed, but if your still interested email me and ill try and find the plans and scan them at school.

L8rz,
Deepak Jr.
 

Robert P. Jones

Second Unit
Joined
Jun 18, 1999
Messages
289
The lenses used in RPTVs are multi-element lenses, usually 4 lenses per color's barrel. The use of a fresnel single element lens is ludicrous by comparison, in terms of potential fidelity of image. The refraction alone degrades the picture at the edges, with rainbowing all over the place.

The intensity of the image in RPTVs is tripled by using 3 guns, none of which use a light-limiting shadow mask, as is used in directviews, to separate the colors. This is not necessary in monochromatic CRTs, allowing 2 to 3 times more light output per CRT, in RPTVs.

The light dissipation by using one fresnel lens on a regular DVTV will be directly proportional to the sizes involved. If the image on the wall is to be 4 times bigger than the source, it will be 4 times dimmer also. That is, when the fresnel lens is transmitting 100% of the light output of the source set, and when the wall is reflecting back a high rate of light output. Very optimistic.

Lastly, the lens turns the image upside down. All RPTV images start out upside down before they get to the screen they are sent to, which we look at.

If you try to turn your TV upside down, the purity will be hosed by the relative change in the Earth's magnetic field, until you turn it right side up again. The only correct way to do it is to redo the yoke connections inside the direct view, changing it to upside down on the source screen.

If you send it upwards at all towards a wall, you will also get keystone effect.

I tried all this about 30 years ago. "Disappointing" doesn't even come close. That's why I don't even think about this type of thing anymore.

I also tried the 27" fresnel lens in front of the 13" directview, which caused streaks going out from center, on anything bright. So much for taking a 27" magnifying glass to your DV and trying to call it a bigscreen.

Trust me, it's a silly waste of time. Even the worst mass-produced RPTV will give you a better picture.

Mr Bob
 

Allan Jayne

Senior HTF Member
Joined
Nov 1, 1998
Messages
2,404
Buy a large, perhaps 8-1/2 x 11 inch or more, sheet magnifying glass from a stationery or office store. Get a cardboard box large enough to hold the TV set (19 inch seems best, smaller means a dimmer picture and larger may be too heavy to manage) with space around on all sides for ventilation. Cut a hole in the box and mount the magnifying glass. Turn the TV upside down and face it into the box, using perhaps some books under it to prop it up but not obstructing ventilation slots. In a dark room you should be able to get a quite large although not very sharp and not very bright picture.

Video hints:
http://members.aol.com/ajaynejr/video.htm
 

John-Miles

Screenwriter
Joined
Nov 29, 2001
Messages
1,220
yes it works, no it dosent work well, this is the big screen solution for the MP3 generation who are too whacked out on the shrubbery to think te crap picture is anythign but ... cool mannnnnn.....

you get what you pay for, and this would be great for anythign who does not care about picture quality, if your at this forum then its not for you.
 

Robert P. Jones

Second Unit
Joined
Jun 18, 1999
Messages
289
Couldn't have said it better myself. Great as an experiment and as a curiosity. Abysmal performance, for the eyes of anyone hanging out around here.

Mr Bob
 

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