TV's as Monitors.
From the Apple // BBS.
Copyright (c) 1990 Apple Users' Group, Sydney
Republished from Applecations, a publication of the Apple Users' Group, Sydney, Australia.
Here are a few messages taken from the AUG Apple // BBS on the subject of using television screens as monitors. They are reproduced here for the benefit of other members who may be interested.
Message 1856 read 47 times, subject : Monitors
Posted on the 18-Jan-90 at 10:55
From user #17
Has anyone tried putting the PAL output from an Apple //e into the "video in" socket on a TV (thus bypassing the RF modulator). How does the definition compare with a dedicated monitor?
[Editor's note: Not all Apple //es are PAL. The platinum //e and the //GS are both NTSC]
Message 1863 read 34 times, subject : TV
Posted on the 18-Jan-90 at 23:55
From user #163
Hi Peggy,
I think my answer is yes. I often used to run my //c with its RF lead into a colour TV before I got my IIe colour monitor. In fact, we once videotaped an entire game, going through all the steps, all the graphics to its conclusion. We then out a sound track down describing the correct commands. The imgage was good.. I just had to tune a VCR channel to the right frequency, or the TV set .
Regards,
{_} ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Jules Black Logo
Message 1867 read 44 times, subject : TV
Posted on the 20-Jan-90 at 13:47
From user #17
Thank you Jules. Since I put up that message my green screen fell flat on its face and I borrowed someone's TV to try it. I was very disappointed. It did, as you say, work OK (once I remembered to switch the DIP switch from Mono to Colour) but the colours were very washed out compared to an RGB, and worst of all the definition was so bad that 80 col wasn't usable.
Maybe the //c's work better for this. Certainly I have tried RF once or twice and it was totally hopeless. But my Apple puts out a lot of TV interference anyway.
It would be rather fun to videotape a game. I hadn't thought of that!
Message 1890 read 33 times, subject : Monitors
Posted on the 23-Jan-90 at 22:31
From user #514
You will find what ever system you have that if you attach a TV to the computer, 80 columns will always be blury. This is because a TV doesn't have the same resolution(relative pitch dot size), to the average computer monitor.
Grant Kwai
Message 1907 read 33 times, subject : TV's as monitors
Posted on the 26-Jan-90 at 21:35
From user #385
Peggy,
I think the main problem may be that in the resolution of the TV is about equivalent to a 280 * 192 pixel screen. Since a TV has only scan lines rather than lines and rows as in a monitor, cramming the display of over a particular resolution causes the positioniong of a particular dot to be displayed halfway on a line. This is definitely the case with 80 col. another limiting factor may be the bandwidth of the TV's vieo signal, it must be at least 18 mhz wide to even recieve the signal!! Apple ]['s of course, will all produce low-res graphics in 16 colours, these come up well on a tv, as does 40 col text. double hi res and 80 col text look blurred because they are. A TV is physically incapable of displaying the info
Mike ---- Now in Canberra!! Nice place to live.
certainly more geologically stable than
Newcastle, and the money is better.
Message 1910 read 31 times, subject : Monitor Vs TV
Posted on the 27-Jan-90 at 09:48
From user #163
Peggy,
You'll have to talk to a real vidiot for the full answer, but it goes something llike this. In the same way a radio receives and reproduces sound, but your HiFi has individual components going thru an amp en route to your speakers, and your set can't play radio unless you have a tuner attached, a TV MONITOR is visually what speakers are aurally. No picture is visible unless you plug in a TV TUNER. Thus all the components in the monitor are purely dedicated to image production, and not multitasked thus better quality, resolution, etc.
Further, monitors, and this is where the vidiot will back me up or shoot me down, have extra gadgetry over & above yer standard TV set such as what are called COMB FILTERS which clean up the picture before sending it to the screen. They
will perceive a ghosted image and compare it to the main signal and filter it out, making for a crisper, cleaner picture. The Sony "Black" series monitors are considered state of the art for monitors, as far as I know.
Regards,
_
{_} ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Jules Black Logo
Message 1877 read 39 times, subject : Tv as Monitors
Posted on the 29-Jan-90 at 12:33
From user #514
TV's may have the same number of pixels as a monitor but what about the size difference? You will find that a TV has a much larger Dot Pitch than your average minitor leading to a more fuzzy output.
Grant
Message 1825 read 36 times, subject : TVs as monitors...
Posted on the 30-Jan-90 at 09:27
From user #17
Thankyou, Grant, Michael and Jules. Clearly my view of how a TV/monitor works is very simplistic. (Dot pitch? Bandwidth?). Anyway, there is obviously more to a good PAL signal than simply bypassing the tuner. I think I've been spoiled too, by my VGA screen which has dots so small you can't see them without a magnifying glass. (I can't, anyway!).
Message 1919 read 41 times, subject : TV AS MONITOR
Posted on the 01-Feb-90 at 17:27
From user #190
In 1987 there was an artiicle published by Electronics Australia which outlined the modifications to make to a TV if you wanted to make it into a monitor. The mods worked for apples on composite video mode only, but you could theoretically do it for RGB mode on an apple with an rgb card, by giggling the output transistors (of the TV) base pin to the colour burst signal for each colour.
Ring Electronics Australia (their ph.# in the magazine) and ask them to scan their database for the article and you can get a copy of it for less than $1.
Mike Carlton 190
Message 1921 read 39 times, subject : monitors, TV's
Posted on the 01-Feb-90 at 17:33
From user #190
I have tried it and dedicated monitors leave TV's for DEAD. Remember that TV's were designed for distance viewing, not
close up stuff like fine - pitch monitors and you'll begin to see TV set's limitations.
Message 1796 read 36 times, subject : TV's as monitors
Posted on the 03-Feb-90 at 05:55
From user #104
Composite video consists of a high definition b&w component mixed with a low definition colour signal - a compromise that works well with pictures because of the high sensitivity of the eye to intensity changes but relatively poor sensitivity to colour changes. In contrast, RGB signals do not make such compromise and transmit both colour and intensity information at high definition.
So to get a better picture, you should ideally bypass more than just the RF tuner stage.
Anyway, VGA certainly looks good though I prefer the crispness of a monochrome monitor for text (even over the Mac II's colour monitor).
- Ken.

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