View Full Version : Test pattern?


Kamakiri
12-27-2011, 10:56 AM
I have to do a proper linearity adjustment on my '63 Zenith portable, and was wondering how everyone here does theirs? A television analyst, a DVD with a test pattern, SWAG it, or.....?

maxhifi
12-27-2011, 11:05 AM
I bought a home theatre setup DVD, which has color bars, cross hatch, dots, etc.

Feed it into a VCR, and then VCR into TV

I don't trust my ancient unrestored TV analyst to have any better linearity than the ancient TV I'm trying to align.

bob91343
12-27-2011, 11:08 AM
I have a color bar generator for sale.

earlyfilm
12-27-2011, 12:29 PM
I have to do a proper linearity adjustment . . . .

You can get a custom DVD created here and the money goes to a good cause:

http://www.earlytelevision.org/for_sale.html

Jas.

Kamakiri
12-27-2011, 12:59 PM
Good call, I just ordered one!

Electronic M
12-27-2011, 01:42 PM
I tend to use my 1970's SS Heathkit generators.

Celt
12-27-2011, 05:20 PM
I always liked this one which I refer to as "Old boring B&W movie about Indians". :D

http://3.bp.blogspot.com/-cMUpqls6ex4/TW6dUMG66lI/AAAAAAAACsM/fb10X-yd8Vk/s1600/TV-Test-Pattern1.jpg

Jeffhs
12-28-2011, 12:16 AM
The old round test patterns (Indian head and ones used by local stations) aren't needed much anymore with sets from about the 1980s to now (especially the latter), which is probably why TV stations, the few that that still sign off at one or 2 a.m., anyway, use the color bar test chart, with their call signs, channel numbers and city of license in the black area below the bars, but ahead of the large white square at the extreme right edge of the chart. The round pattern is useful when adjusting image proportions (height, linearity, width) on old sets that have variable controls for such, while the color charts can be put to good use when adjusting the 3.58-MHz color burst phase (or to diagnose color registration problems) on vintage color sets.

Some local TV stations put their call signs and channel number on the Indian head pattern as well. Many years before American and Canadian television went digital (also before I had cable), I remember seeing a pattern from CFPL-TV in London, Ontario with just that information at the top of the pattern. I could also get Windsor's CKLW-TV (now CBET) channel 9 when the conditions were right, but I don't remember ever seeing their location and channel info on their test pattern.

At least one Cleveland TV station (NBC affiliate WKYC on channel 3) used a round test pattern with color segments built right into the pattern. Never saw anything like it; in fact, I think that station was the only Cleveland TV station to use such a unique test pattern. Channel 5 had a standard round pattern, as did channel 8, although 8's pattern also, IIRC, had color segments incorporated into it. Cleveland's PBS channel 25, which first signed on in 1965, had a round b&w pattern, no color bars or segments; however, when Cleveland's first commercial UHF station went on the air in 1968, it used a squarish test pattern with one small color bar chart at the top, IIRC. The station's call letters were placed below that chart, with one letter of the call sign appearing directly over the vertical resolution test wedge.

Channel 19's test signal was simply a color chart, with the station's call sign and location info at the base of the chart -- again, very near the white square at the right edge. An independent station on channel 55 (now an affiliate of The CW) that went on the air in 1985 in the Cleveland area, but was licensed to and was intended to serve an area 30 miles southwest of the city, also used a color chart; somewhere, I have a VHS video tape on which I recorded the station's test signal after the end of a program. The station is WBNX-TV, CW55, Akron-Cleveland, Ohio. To the best of my knowledge and belief, however, they never used a round test pattern; neither, for that matter, did Cleveland's original channel 61, Kaiser Broadcasting WKBF-TV (now WQHS-TV Univision 61). Maybe by this time (late '60s), traditional test patterns had gone out of style? :scratch2:

ctc17
12-28-2011, 12:39 AM
The Leader LCG400 ntsc generator dominates. Nothing comes close. The DVD would be a second choice.

jr_tech
12-28-2011, 12:54 AM
Here is a post that I made several years ago showing the 2F21 "Monoscope" CRT used to generate the "Indian Head" pattern. RCA would indeed provide custom versions of the pattern with call letters and perhaps other info printed on the target.

http://www.videokarma.org/showpost.php?p=2966865&postcount=29

jr

Phil Nelson
12-28-2011, 01:58 AM
I use a Leader pattern generator most of the time. It has a small workbench footprint and works great. At other times, for various reasons, I may use the Sencore VA62 video analyzer, or a test pattern DVD, or (when feeling nostalgic and not very scientific) the BK 1077B TV analyst.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

W.B.
12-28-2011, 04:42 AM
The old round test patterns (Indian head and ones used by local stations) aren't needed much anymore with sets from about the 1980s to now (especially the latter), which is probably why TV stations, the few that that still sign off at one or 2 a.m., anyway, use the color bar test chart, with their call signs, channel numbers and city of license in the black area below the bars, but ahead of the large white square at the extreme right edge of the chart. The round pattern is useful when adjusting image proportions (height, linearity, width) on old sets that have variable controls for such, while the color charts can be put to good use when adjusting the 3.58-MHz color burst phase (or to diagnose color registration problems) on vintage color sets.

Some local TV stations put their call signs and channel number on the Indian head pattern as well. Many years before American and Canadian television went digital (also before I had cable), I remember seeing a pattern from CFPL-TV in London, Ontario with just that information at the top of the pattern. I could also get Windsor's CKLW-TV (now CBET) channel 9 when the conditions were right, but I don't remember ever seeing their location and channel info on their test pattern.

At least one Cleveland TV station (NBC affiliate WKYC on channel 3) used a round test pattern with color segments built right into the pattern. Never saw anything like it; in fact, I think that station was the only Cleveland TV station to use such a unique test pattern. Channel 5 had a standard round pattern, as did channel 8, although 8's pattern also, IIRC, had color segments incorporated into it. Cleveland's PBS channel 25, which first signed on in 1965, had a round b&w pattern, no color bars or segments; however, when Cleveland's first commercial UHF station went on the air in 1968, it used a squarish test pattern with one small color bar chart at the top, IIRC. The station's call letters were placed below that chart, with one letter of the call sign appearing directly over the vertical resolution test wedge.

Channel 19's test signal was simply a color chart, with the station's call sign and location info at the base of the chart -- again, very near the white square at the right edge. An independent station on channel 55 (now an affiliate of The CW) that went on the air in 1985 in the Cleveland area, but was licensed to and was intended to serve an area 30 miles southwest of the city, also used a color chart; somewhere, I have a VHS video tape on which I recorded the station's test signal after the end of a program. The station is WBNX-TV, CW55, Akron-Cleveland, Ohio. To the best of my knowledge and belief, however, they never used a round test pattern; neither, for that matter, did Cleveland's original channel 61, Kaiser Broadcasting WKBF-TV (now WQHS-TV Univision 61). Maybe by this time (late '60s), traditional test patterns had gone out of style? :scratch2:
The circular color test pattern used by WKYC beginning around 1968 or at the latest 1970 (prior to then, they used the customary B&W NBC bullseye) was used by many different TV stations across the country, but mostly in the eastern half of the continental U.S.; very few in the western half used it. Other stations using this pattern (with a few alterations over the years) included:
- WIBF (Channel 29, later WTAF and now WTXF), Philadelphia, PA
- WNDT (Channel 13, now WNET), Newark, NJ/New York City*
- WNJU (Channel 47), Linden/Newark, NJ*
- WFLD (Channel 32), Chicago
- WLS (Channel 7), Chicago (the famed "Sears Tower/Circular Polarization" layout)
- WHBF (Channel 4), Rock Island, IL
- WNJT (Channel 52), Trenton, NJ
- WTVS (Channel 56), Detroit
- WMUR (Channel 9), Manchester, NH
- WAPA (Channel 4), San Juan, PR*
- WOR-TV (Channel 9), New York*
- WETA (Channel 26), Washington, DC
- WYTV (Channel 33), Youngstown, OH
- WOUB (Channel 20), Athens, OH / WOUC (Channel 44), Cambridge, OH (both stations on one pattern)
- WLVI (Channel 56), Cambridge/Boston
- WTTG (Channel 5), Washington, DC*
- WKBS (Channel 48), Burlington/Philadelphia*
- WSMW (Channel 27, now WUNI), Worcester, MA
- KGO (Channel 7), San Francisco*
* custom layout with station logos included
and a few had that pattern in varying black-and-white form, such as:
- KAET (Channel 8), Phoenix
- WQED (Channel 13), Pittsburgh*
- WMAH (Channel 19), Biloxi, MS and WMAW (Channel 14), Meridian, MS
- YSR-TV (Canal 2), El Salvador
(I was also informed that WRGB Channel 6 in Schenectady, NY, also used it, but have not seen any examples.)
By the late 1970's, that particular color TP design was turned upside-down; as such it was used by WRC-TV (Channel 4), Washington, DC, and the stations of South Dakota Public Television (including KUSD Channel 2 in Vermillion). I.I.N.M., it was also used in that upside-down form by KHET (Channel 11), Honolulu / KMEB (Channel 10), Wailuku, in Hawaii.

Here are two particular variations:

http://www.non-linearproductions.com/underground/1960s-Color-TP-v1a.jpg http://www.non-linearproductions.com/underground/1960s-Color-TP-v1b.jpg

(Would anyone know which other stations across the country would've used this overall pattern, in either form?)

After c.1979-80, there was a redesign of the pattern with a completely different set of colors:

http://www.non-linearproductions.com/underground/1980-Color-TP.jpg

which, in this form, was used by the following stations (again, a partial list):
- WABC (Channel 7), New York*
- WPIX (Channel 11), New York
- WKBW (Channel 7), Buffalo, NY
- WTVE (Channel 51), Reading, PA
- WTTG*
- WOUB/WOUC
- WCGV (Channel 24), Milwaukee
- WSBK (Channel 38), Boston
- WOLF (Channel 38), Scranton, PA
- WNEV (Channel 7 - formerly WNAC, now WHDH), Boston
- WTTE (Channel 28), Columbus, OH
- WICZ (Channel 40), Binghamton, NY
- WVAH (Channel 23 - now on Channel 11), Charleston/Huntington, WV
As with the earlier pattern, two Mississippi public TV stations - WMAH, plus WMAV (Channel 18) in Oxford-University - aired this pattern in a form of black-and-white which apparently entailed running only the red channel across the other two (green and blue) channels. And again, can anyone advise which other stations would have used this?

The selfsame NBC bullseye test pattern that was used as the basis for this color pattern, was also adapted by their New York outlet WNBC (Channel 4) for a completely different color test pattern that was used beginning in 1975 and well into the late 1980's/early '90's:

http://www.non-linearproductions.com/underground/1970s-Color-TP-v1a.jpg

WVIZ had used a color adaptation of the 1956 RETMA/EIA resolution chart; which was also in use for some two decades at WUAB (Channel 43).

And the Indian head was not the only pattern from RCA for use on monoscopes; they also had a lined bullseye test pattern which was also in use by a number of stations in the U.S. and Canada (another station in the latter country being Hamilton's CHCH Channel 11), as seen below:

http://www.non-linearproductions.com/underground/Alt-Mono-TPv2.jpg

(Some stations used both Indian and RCA bullseye, namely KRLD Channel 4, now KDFW, in Dallas.)

This pattern (albeit without the particular wedges on the top right and bottom left sides) was also altered with a few other elements by the stations of Crosley/Avco Broadcasting beginning in the late 1950's and in use at their TV stations (verified as at WLWT Channel 5, Cincinnati; WLWD Channel 2, now WDTN, Dayton; and WLWI Channel 13, now WTHR, Indianapolis).

And who could forget the test pattern of CBS-owned and -affiliated stations, whose layout has been compared by DX'ers to an archery target:

http://www.non-linearproductions.com/underground/1948-CBS-TP.jpg

Kamakiri
12-28-2011, 08:06 AM
I remember the color test pattern on WKBW. Oddly enough, it came on about a half hour before the station signed on the air in the morning. Before that, it was the typical color bars. I always thought, man, those TV repairmen that have to get their sets aligned sure do have to get up early in the morning!

Kamakiri
12-28-2011, 08:09 AM
I always liked this one which I refer to as "Old boring B&W movie about Indians". :D

http://3.bp.blogspot.com/-cMUpqls6ex4/TW6dUMG66lI/AAAAAAAACsM/fb10X-yd8Vk/s1600/TV-Test-Pattern1.jpg

This brings up an interesting point. What was the meaning of the numbers in the diagram? While they may be measurements of some kind, one can only imagine that it's actually a points score for a TV based bean bag toss :D

Electronic M
12-28-2011, 01:47 PM
This brings up an interesting point. What was the meaning of the numbers in the diagram? While they may be measurements of some kind, one can only imagine that it's actually a points score for a TV based bean bag toss :D
Aah, TV Indian bean bag toss a favorite among late night drinking buddies and early risers that owned protelgram projectors. :lmao:

jr_tech
12-28-2011, 01:56 PM
This brings up an interesting point. What was the meaning of the numbers in the diagram? While they may be measurements of some kind, one can only imagine that it's actually a points score for a TV based bean bag toss :D

I believe that they define the resolution scale in various parts of the "wedges" from 200 to 450 lines in the center and 200 to 350 at the corners

jr

old_tv_nut
12-28-2011, 03:28 PM
I believe that they define the resolution scale in various parts of the "wedges" from 200 to 450 lines in the center and 200 to 350 at the corners

jr

Yes, resolution in "TV Lines per picture height." 330 lines is the most you could get on a broadcast signal with a black and white set (or color set with comb filter). Maybe 270 lines horizontal with a color set with 3.58 MHz trap.

jr_tech
12-28-2011, 05:43 PM
So one would measure Horizontal resolution in terms of "lines per picture (vertical) height"? seems strange! :scratch2:
I would think that normalizing the measurement to CRT diameter/diagonal or width would produce data that would be more consistent... "portholes" got a big break with the "lines per picture height" definition.

jr

W.B.
12-28-2011, 06:37 PM
I believe that they define the resolution scale in various parts of the "wedges" from 200 to 450 lines in the center and 200 to 350 at the corners
NBC, oddly enough, had a layout of their famed "bullseye" pattern in which they explained what the significance of the wedge calibration dots as positioned on each side of their horizontal and vertical wedges, were:

http://www.non-linearproductions.com/underground/1947-NBC-TP2.jpg

Alas, I haven't heard, seen or read anything about this variation being seen on the air.

NOTE: 200 TV lines = 2.5 MHz (or "mc," as it was known as of 1947).

Kamakiri
12-28-2011, 08:10 PM
So one would measure Horizontal resolution in terms of "lines per picture (vertical) height"? seems strange! :scratch2:
I would think that normalizing the measurement to CRT diameter/diagonal or width would produce data that would be more consistent... "portholes" got a big break with the "lines per picture height" definition.

jr

Well not only that, but imagine the technician with a magnifying glass trying to count each line to be sure of the perfect picture!

old_tv_nut
12-28-2011, 09:03 PM
So one would measure Horizontal resolution in terms of "lines per picture (vertical) height"? seems strange! :scratch2:
I would think that normalizing the measurement to CRT diameter/diagonal or width would produce data that would be more consistent... "portholes" got a big break with the "lines per picture height" definition.

jr

Doesn't matter what you normalize to, just so you normalize to something. Probably because the scanning lines are arranged vertically one below another, the vertical dimension was chosen. "330 lines per picture height" of horizontal resolution gives 440 total "lines" of resolution per picture width since the width is 4/3 times the height.

bandersen
12-28-2011, 10:42 PM
Aren't there always 525 lines (262 1/2 interlaced) vertical ? Minus a few for closed caption and other info that is.

old_tv_nut
12-29-2011, 10:25 AM
Aren't there always 525 lines (262 1/2 interlaced) vertical ? Minus a few for closed caption and other info that is.

OK, this is a very old concept, but here goes:

There are 525 total lines, but only 483 active lines due to vertical blanking. Let's just call it 480 for rough calculation (which also matches a common computer image format).
Because the lines sample the picture vertically (just like the rows of pixels in a digital picture), they cannot provide a full 480 lines of resolution for ordinary pictures - they could only do that if the picture details happened to line up exactly with the line structure. The ratio of practical viewable resolution is called the "Kell factor" after Ray Kell, who published the original research in 1934. There is an additional factor due to interlace causing interline flicker - how strong this is depends on the observer and the amount of detail contrast in the image. The first NTSC (1941) adopted an over-all factor of 0.7 for the achievable resolution compared to the number of active lines. Along with this they specified a combination of baseband video signal bandwidth (4.2 MHz) and active scan lines (486) that would give equal resolution per picture height vertically and horizontally, and also fit in a 6 MHz channel using vestigial sideband modulation and including a sound carrier. 480x0.7 = ~330, the accepted usable resolution - your mileage may vary, and there have been a lot of useless arguments over the years as to whether the useful vertical resolution number is exactly correct.

A few of the active lines were later devoted to other things like test signals, data, and closed captions, leaving 483 containing picture.

jr_tech
12-29-2011, 02:04 PM
Interesting info! Thanks!
Does this Kell/NTSC facto apply in about the same way to DTV or must another factor be used? Perhaps a different factor for 1080i than 720p?

jr

old_tv_nut
12-29-2011, 09:32 PM
Interesting info! Thanks!
Does this Kell/NTSC facto apply in about the same way to DTV or must another factor be used? Perhaps a different factor for 1080i than 720p?

jr

HDTV makes a little difference, in that the line structure is smaller/finer compared to the overall picture size. Some of the effects of interlace can be reduced with progressive display, as on a plasma or LCD TV, but the conversion to progressive is never perfect. Thus, 1920x1080 interlace generally has noticeably better resolution on static scenes, but 1280x720 progressive generally looks better on sports.

The best for resolution and motion at the same time would be 1920x1080P at 60 frames per second, but there are no sources at that rate. Blu-Ray discs carry 1920x1080P movies at 24 frames per second, which is converted to 60 frames for display - this is close to the ultimate depending on how well the conversion is done.

By the way, digital images have the same sort of factor in the horizontal direction because they are made of discrete pixels in both directions.
Without interlace, the factor is perhaps 0.9 instead of 0.7. The SMPTE standard for digitizing NTSC or PAL component video has filters that start to roll off (70% response) at a factor of 0.85. I estimate that for a test pattern you can still see the resolution in the wedges when the amplitude is down to 10%, which is probably around a factor of 0.9. So, a system with 640x480 pixels scanned progressively and displayed progressively would have a useful resolution of about 430 TV lines per picture height (lph) both vertically and horizontally. The 1280x720 progressive standard gives about 648 lph both vertical and horizontal, and the 1920x1080 interlaced system gives about 972 lph horizontal resolution, and a variable amount of vertical depending on camera settings and motion, nominally 756 lph.

jr_tech
12-30-2011, 01:51 PM
Wow! thanks again! I am always amazed by the depth of knowledge to be found on this board!

jr

bandersen
12-30-2011, 02:54 PM
I thank you as well. I think I understand the concepts now.

Kamakiri
12-31-2011, 08:49 AM
The information in this post I felt was so invaluable, that I created a forum specifically around the topic. Thanks to old tv nut for such an eloquent explanation!

4343
06-09-2012, 07:59 PM
Well not only that, but imagine the technician with a magnifying glass trying to count each line to be sure of the perfect picture!

In the 80's, that was me. We used a digital monoscope (minus the Indian head) that had 800 lines resolution wedges in the horizontal for checking tube cameras that were often specced out to 700 lines (for luma only).

I used that generator to align my 25" Sony Profeel Monitor to get the minimum overscan possible when I bought it in about '87. Last year I put a tape of the test pattern on it and could see no change in picture size...

W3XWT
07-25-2012, 08:48 PM
On the color wedge test pattern, my favorite was WOLO-25, which had its city of license in the lower right-hand quad as "COLUMBIA, SOUTH, CAROLINA". It was also one of those stations that attempted to cool the klystrons with tap water. Hard tap water at that!

Jeffhs
07-26-2012, 12:53 PM
Cleveland's WKYC-TV (NBC affiliate) had a color-wedge test pattern in the '60s-'70s that showed its city of license in the same place the NC station's did. The Cleveland station's pattern also showed, briefly (for only a short time, IIRC), the old NBC "snake" logo in one corner, with the city of license appearing elsewhere on the pattern; I forget where.

Local TV stations and networks still use a color bar test chart, with the ID or the words "please stand by" in the center of it, when there are technical problems (in fact, a channel that no longer transmits an analog signal on the cable system here shows only a color test chart on that channel, with no ID or anything else), but the circular and box-shaped test patterns (the latter appearing on at least two UHF TV stations in Cleveland and likely in other cities, when US and Canadian TV stations still signed off for the night and on again the next morning) have gone the way of analog NTSC TV and reel-to-reel video tape recorders.

Opcom
07-26-2012, 10:10 PM
The subject of patterns is one of the most fun because they are both entertaining, weird, and useful. There is a whole slew of unusual patterns on Laserdisc test discs and not all are static. Like TV patterns, many of those are made for using a scope to check signals in the equipment and not for monitor candy.

Over the years I have collected a few commercial pattern generators and have gotten rid of the Heathkits and such for the most part. I use a Tektronix 1400 series or Leitch DTG-1010 generator in the lab, or a portable Sony DSG-10 hand-held in the house if I am lazy (but it is missing the blue filter card, believe that is what goes in the slot). Sometimes I use a home made monochrome multiburst generator. I didn't build it but it came from an unidentified TV station's basement. I suppose an engineer built it up, perhaps before color as it is all transistors no IC, and it makes no color burst so it was likely intended to tweak up high resolution monochrome studio monitors. It's all perf-boards and hand wired with DYMO strips for labeling. A holy relic I have kept to honor the work of the unknown builder. I also have a couple of B&K flying spot scanners and those are nice because an approximately 4" negative film can be put in, and one could make one's own pattern that way but I have not done it because I don't have any experience with film and printing on transparency sheets has not yielded very good results. (those B&K manuals are on bunkerofdoom.com)

If there is a good sharp image of the Indian head pattern, I'd sure like to see it, seriously have a copy to digitize.

In Dallas, it's not easy to find a test pattern and most of the TV stations never seem to go off the air.

Instead they put on these awful droning or screaming, and lying infomercials all night, and even those sometimes have commercials in them. Who are the many brainwashed viewers hurrying to call and get that weight loss and mens' function pills combo, with the hair tonic thrown in? :yuck: But wait, if you order in the next 10 minutes we'll throw in these love pills for the wife :smlove:! Now due to high call volumes, we're overwhelmed and only people with last names from A-J can call now, all others must call tomorrow! :screwy: I guarantee that makes the K-Z cattle virtually leap to the phones! :yippy:
I pity those TV-holics that work days and have only those things to watch.

Don't even have the decency to show old movies and play the National Anthem at some point each 24 hours. I miss that. I imagine they would play the Anthem if someone would buy the airtime. here's a plan. pay it for a couple months, then end the contract. people will call in angry about it being stopped. Would they dare to say they had to be -paid- to do it?

Einar72
07-28-2012, 11:23 AM
One of the TV camera collectors not often seen on VK sells them on his website, apparently saved from a dumpster by a worker who was demolishing the building they were in...

http://pharis-video.com/p5013.htm

No affiliation here, but I do have Delaware Native tribe ancestors from NJ. Wondered if one wandered into the RCA building one day...

Jeffhs
07-28-2012, 04:51 PM
Television here in northeastern Ohio is also non-stop, with no Cleveland station signing off for any reason except technical problems. I used to get up a five a. m. just to watch the test patterns from the three (at the time, '60s-'70s and until all TV here went full-time) network affiliates before they signed on. It was also interesting to watch after the local stations had signed off; occasionally I'd see a test pattern from a distant station, usually on channel 3 or 5. I live in the Great Lakes region near Michigan and southwestern Ontario, and I would sometimes see actual programming from station WNEM-TV in Saginaw on channel 5 after Cleveland's ABC affiliate had called it quits for the night. I'd also see programs, and occasionally a test pattern, from channel 12 in Erie, Pennsylvania, channel 10 in London, Ontario, channels 11 and 13 in Toledo, Ohio, channels 2, 4 and 7 from Detroit, and a host of UHF station patterns as well.

I wonder about those late-night infomercials too. Not that they bother me (I often stay up late at night and will usually watch a DVD if there is nothing to interest me on standard broadcast TV), but I do think they waste the stations' RF and DC power, not to mention raising the question in my mind of who actually watches these things at the unearthly hours at which they air. The TV networks and local stations are trying to gain early-morning viewers by airing newscasts at 4:30 a. m., but sometimes I wonder who is actually up watching TV at that hour; five or six a.m. makes more sense to me. The only people I can think of who might watch those 4:30 newscasts would be those who begin their work day unusually early, say at five or six in the morning.

I have heard that some infomercials, known as "paid" programs or advertisements, can and do actually generate revenue for TV stations whether or not anyone watches them. I cannot for the life of me see how that is possible. :scratch2: These things cannot, to my way of thinking, raise one red cent if no one is watching. One of these days I'd like to find out just how paid programs/advertisements work to a TV station's advantage, and whether they are really worth the time and money the stations spend to put them on at hours when most folks are sound asleep.

cbenham
08-25-2012, 03:22 AM
I always liked this one which I refer to as "Old boring B&W movie about Indians". :D

Here's my favorite test pattern...
Cliff

Telecruiser
10-09-2012, 11:34 PM
Google "TV Test Pattern" in their "images" area. There are a ton of them available as jpeg's. If you want to actually use one to set up your old video equipment look for a Micca Digital Media Player at Amazon.com http://www.amazon.com/Micca-MPlay-Digital-Player-Drives/dp/B003D0WIQS/ref=sr_1_3?ie=UTF8&qid=1349839756&sr=8-3&keywords=micca or eleswhere. You can save the test pattern on a regular SD memory card, and the Micca player will turn it into composite video. The good news is the player is less than $30. I have one on my work bench and have a variety of test patterns and color bars stored on it. I love it.

W.B.
12-20-2015, 10:20 PM
As I'd noted in earlier posts, the color circular test pattern design originally had two variations, coded by region as per the order of a diagonal black/white wedge at the bottom of the outer lower right quadrant. TP's with this layout:

http://www.non-linearproductions.com/underground/1960s-Color-TP-v1d.jpg

were for stations east of the Mississippi with 'W' calls; three stations were confirmed to use it - WIBF (later WTAF and now WTXF) Channel 29 in Philadelphia, PA; WFLD Channel 32 in Chicago, IL; and WNDT (now WNET) Channel 13 in Newark, NJ / New York City (the last actually confirmed to be color). And as laid out here:

http://www.non-linearproductions.com/underground/1960s-Color-TP-v1c.jpg

was for west of the Mississippi with 'K' calls. Only one station, to date, has been confirmed to use it, and then with a B&W print: KAET (Channel 8) in Phoenix, AZ.

My question is, how many "old-timers" on this forum remember either layout, and who else would've used either prior to the wedges at bottom right being eliminated? Certainly those stations weren't the only ones . . . ?

centralradio
02-18-2016, 10:29 PM
Wow .I remember the days of the late night test patterns.Thanks Telecruiser for the info on the video playback device .I've been looking for something like that for years.

CoogarXR
02-19-2016, 09:47 AM
I have a small SD-Card/CF video player (it's about the size of a cassette tape case). I have an SD card with movies on it for long-run testing, and I have an SD card with test pattern JPGs (it does a slideshow). It has composite+audio and VGA outputs. It's pretty handy, and tiny on the bench.

I also have a SD card with a single solid white image. It's good for flushing screen burn-in on plasma TVs.

W.B.
06-16-2016, 10:28 PM
OK, this is a very old concept, but here goes:

There are 525 total lines, but only 483 active lines due to vertical blanking. Let's just call it 480 for rough calculation (which also matches a common computer image format).
Because the lines sample the picture vertically (just like the rows of pixels in a digital picture), they cannot provide a full 480 lines of resolution for ordinary pictures - they could only do that if the picture details happened to line up exactly with the line structure. The ratio of practical viewable resolution is called the "Kell factor" after Ray Kell, who published the original research in 1934. There is an additional factor due to interlace causing interline flicker - how strong this is depends on the observer and the amount of detail contrast in the image. The first NTSC (1941) adopted an over-all factor of 0.7 for the achievable resolution compared to the number of active lines. Along with this they specified a combination of baseband video signal bandwidth (4.2 MHz) and active scan lines (486) that would give equal resolution per picture height vertically and horizontally, and also fit in a 6 MHz channel using vestigial sideband modulation and including a sound carrier. 480x0.7 = ~330, the accepted usable resolution - your mileage may vary, and there have been a lot of useless arguments over the years as to whether the useful vertical resolution number is exactly correct.

A few of the active lines were later devoted to other things like test signals, data, and closed captions, leaving 483 containing picture.
A video transfer firm that deals with 2" quad transfers, has shown some screengrabs in full D1 720 x 486 frame - and only 484 lines were actually used, with the top two lines (lines 21 and 283) unused, and those being used consisting of 22 - 263 and 284 - 525. Apparently, 483 was in the analogue realm in that sense, and thus by digital frame grabs one can see by each "half-line," 484 lines in essence.

centralradio
07-26-2016, 01:49 AM
I have a small SD-Card/CF video player (it's about the size of a cassette tape case). I have an SD card with movies on it for long-run testing, and I have an SD card with test pattern JPGs (it does a slideshow). It has composite+audio and VGA outputs. It's pretty handy, and tiny on the bench.

I also have a SD card with a single solid white image. It's good for flushing screen burn-in on plasma TVs.

Not to skew this topic off course .Whats the name of the SD-Card/CF video player you are using.I've been looking for one for a while now.Thanks.

MIPS
07-26-2016, 10:42 PM
In the early days it was a VHS tape I recorded a test pattern to using a VGA to composite adapter.

CoogarXR
07-27-2016, 08:21 AM
Not to skew this topic off course .Whats the name of the SD-Card/CF video player you are using.I've been looking for one for a while now.Thanks.

My work area is under construction right now, all my equipment is buried, lol. But I know I have two of them, one is a no-name chinese unit, it has a remote and everything. The other one is white, it has a brand name, but I can't remember for the life of me what it is...

I looked on ebay and google, of course I can't find a picture of one like mine. But if you search for "sd cf media player" there are a ton of options out there. Some have HDMI. I wish mine did, I might have to upgrade!

centralradio
07-28-2016, 01:19 AM
My work area is under construction right now, all my equipment is buried, lol. But I know I have two of them, one is a no-name chinese unit, it has a remote and everything. The other one is white, it has a brand name, but I can't remember for the life of me what it is...

I looked on ebay and google, of course I can't find a picture of one like mine. But if you search for "sd cf media player" there are a ton of options out there. Some have HDMI. I wish mine did, I might have to upgrade!

Thanks .I will google it out.

Opcom
06-14-2018, 11:54 PM
long time.. hope to pick up RCA TK-1 with good CRT this weekend. no idea if it will be working or not.