TV tuners and projectors

I'm afraid that in a room which is only partially blacked out, picture quality anywhere near comparable to a TV isn't going to be achieveable with a projector, whatever the specs, whatever the screen, and whatever the price.

One thing which has puzzled me, is why no one has devised a projector using lasers. You can get Red, Blue and Green lasers. You can achieve a high-speed scanning by mirrors suspended in an electromagnetic field. The only snag is lasers are either on or off, so achieving luminescence control (cf a cathode ray tube) is problematic. But surely you could have an LCD shutter ?

LED projectors are under development I believe, but I've never heard of laser technology being applied. If that is the case then presumably there's some kind of fundamental drawback, or one of the big companies would have tried it.

Nothing is obvious apparent in

I very much doubt it when you include a decent screen. Projecting onto a white sheet or wall doesn't give good results. Economy of scale makes the TV better value.

I have a back projection DLP TV. Still on its original lamp at about 10 years old. Used every day for about 3 hours. I do have it on economy mode

- which is still quite 'bright' enough for me.

persistance of the image, I suggest.

More mainstream HID lamps are being used in some projectors now and LEDs are making serious amounts of light, but not yet at the bright enough stage that will keep everybody happy. Still a diy project, but getting better.

Red and green are easy but the blue is a bit problematic as there isn't a cheap semiconductor blue laser at present closest is 400nm purple which is twice one of the 800nm IR pump lasers. The other big problem with coherent light is laser speckle effect which seriously detracts from the image quality - although looks kind of cool in disco smoke etc.

Cheap LED projectors now have the long life but not the brightness and also noisy fans because their USP is being tiny and easily portable. You do get what you pay for with TV projectors although by skipping the fancy 3D and gaming garbage you could probably pick up a bargain at Richer Sounds or some similar discounted end of line shop.

If the OP has no TV at all then I don't know why he doesn't just buy a cheap and cheerful USB tuner stick for £12-£40 depending on the barnd and features. The Chinese one I got recently to use as an SDR was just over a tenner and although incapable of HDTV could do everything else and be repurposed to be a wideband tuner from 100kHz to over 1GHz.

no. they can be throttled quite a bit.

of course. the fact is that arrays of LCD/plasma panels are in the end cheaper. Which are what are used for big sporting events.

Leans on knarled walking stick... I remember in the 1950s we had a back projection TV with Freznel screen that really you had to sit right in front of to see it properly. Biggest screen in the street. grin

Brian

John Lewis are selling 55" LCD TVs for several thousand pounds, which is far more than the DLP projector prices I've seen (which still seem to me to be far to high in price).

Why are screens expensive? Aren't they just a greyish background material coated with tiny glass beads, the sort of thing sold for slide projection, home movies, etc.?

I recently passed a ground floor window inside which a projector was displaying TV on what looked to be a plain white wall. It looked OK, although to be fair it was nearly dark outside.

That's reassuring. Maybe the quoted figures are actually on the conservative side. Amazingly.

I'm starting to think that it might be OK for my situation, except for the price and the power consumption. (Very small room, head of bed ~2.7 metres from wall, computer stuff in corner beside bed, every possible space taken up with furniture. Should be possible to fasten a small projector shelf above the head of the bed and get a 50" picture which could still be viewed albeit at an angle from the PC keyboard if I want to do that instead of slouching on the bed.)

What brand? For TV I would prefer not to have to boot anything, just to push the 'on' button, but I might be interested in it as a wideband tuner plugged into a PC.

That sounds quite hopeful for the future. Right now I'd imagine projectors using them are a bit pricey if available at all.

Recently saw an 84" Ultra HD TV in Apollo 2000 for £16,999 ....

I am wondering just why - if you managed without a TV for 40 years - that the only option now is a top of the range one size wise? Drop the size to about 40" and it becomes hundreds, not thousands.

This one. You need the Realtek RTL2832 chipset for SDR drivers to work.

Takes a while to come since it is shipped from China!

Be aware that SDR isn't for the faint hearted but the drivers and shims to make it all work are fairly well documented online if you search for SDR. I did find some quirks too. My smallest notebooks don't have quite enough grunt to run it properly and I haven't had time to try again on a faster machine. The software to snatch aircraft transponders and plot a radar scan centred on your location is quite amusing too.

It also worked fine as a TV tuner using its own drivers - haven't tried DAB on it yet (but it can't be any worse than my other DAB tuners).

The American home theatre groups are innovating all the time. I followed them a few years ago and have a very effective painted wall in place because of them. In the new location, I'm looking at stretching Lycra over a frame, likely covered with white satin or similar first. The results I've seen are very very good, for not a lot of money.

You have to watch out for low resolutions with the cheap and cheerful ones. The claimed 720p and 1080p is often complete mince, with a native panel inside of 800x600. My own small one is only that, and while it will be getting fitted with a 20 or 30W (or greater) LED assembly over winter, I'm only using it as a test bed for something better later on. I had already built an overhead variant, using a stripped monitor panel and that gave me 720p, which was worthwhile for a couple of years, but it's a big, clunky thing and not portable. Small, neat and cool, is the thing. And ceiling mountable.