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Author Topic: Design Review  (Read 22669 times)
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The Slab Bacon
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« Reply #25 on: June 15, 2008, 09:40:19 AM »

Ed, you prolly wont find them on thatbay for that price, but you do see them at festers for that  kind of money.

Sorry guys, I tried to post a new thread for the scream mod 4x1 but after typing all of the info and attaching the image it blew me out into never never land because the image was in .tif format, and this bbs wont accept it.  I'll have to try to find some way to convert it and post it later.

                                                                the Slab Bacon
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N3DRB The Derb
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« Reply #26 on: June 15, 2008, 12:05:09 PM »

slab, send it to me n I'll convert & post it.
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W4EWH
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« Reply #27 on: June 15, 2008, 07:51:59 PM »

Can you read these ok?

Steve,

Much better, thank you.

I suggest the sysops allow larger files where schematics are concerned: the detail is important and it just doesn't work for me at low resolution.

73,

Bill W1AC
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Steve - WB3HUZ
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« Reply #28 on: June 15, 2008, 08:53:43 PM »

If it's a hand drawn thing, email it to me. I'll do it up with the CAD munky and post.



Ed, you prolly wont find them on thatbay for that price, but you do see them at festers for that  kind of money.

Sorry guys, I tried to post a new thread for the scream mod 4x1 but after typing all of the info and attaching the image it blew me out into never never land because the image was in .tif format, and this bbs wont accept it.  I'll have to try to find some way to convert it and post it later.

                                                                the Slab Bacon
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Steve - WB3HUZ
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« Reply #29 on: June 15, 2008, 09:14:45 PM »

Just a quick reminder, JPEG are to be used with photographs and other images where there are not sharp lines or large amounts of white space. For machine drawn schematics (and clean scans of paper schematics) a GIF or PNG file format will generally render far smaller file sizes than JPEG. Use the correct tool for the job. It should be  pretty easy to post a large schematic without exceeding a few hundred kilobytes. The current limit here is 2 Megs!!  PDF machinations not required.

The original schematic posted by Ed has more than enough resolution when using the proper viewer.




So Heres Rev A.  --


Ed,

Please have mercy on those of us over 50, and supply a schematic with more pixels. My eyes thank you.

Bill W1AC

It is difficult to post schematics as .jpg files, because they get real large real quickly !  I find the best way to do it is to convert a complex schematic to a .PDF (Adobe Acrobat) file, and let the reader make it as large (or small) as desired.  This is how I have all of the schematics on the class E web site.  Seems to work.  However, here is the schematic in both PDF and .JPG formats.  Can you read these ok?

Here is the .PDF http://www.classeradio.com/tube_cathode_modulator.pdf

Here is the image:


Hope this helps!
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steve_qix
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« Reply #30 on: June 15, 2008, 09:32:57 PM »

Just a quick reminder, JPEG are to be used with photographs and other images where there are not sharp lines or large amounts of white space. For machine drawn schematics (and clean scans of paper schematics) a GIF or PNG file format will generally render far smaller file sizes than JPEG. Use the correct tool for the job. It should be  pretty easy to post a large schematic without exceeding a few hundred kilobytes. The current limit here is 2 Megs!!  PDF machinations not required.

The original schematic posted by Ed has more than enough resolution when using the proper viewer.


.GIF is usually smaller, no doubt about it ! This particular schematic did not compress well.  Probably because it was hand drawn.  I tried a number of formats including .gif and it wasn't significantly different.  I have created much more complex schematics using CAD tool, and they really compress to something small!

I personally like .PDF files  .PDF is really great because the format allows on the fly resizing with excellent rendering (Adobe really has it in this area), and various, and very useful print options.  And, it is a standard.  In fact, my book publisher insists on .PDF for all masters for books ! 

Regards,

Steve
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W4EWH
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« Reply #31 on: June 15, 2008, 11:09:31 PM »

For machine drawn schematics (and clean scans of paper schematics) a GIF or PNG file format will generally render far smaller file sizes than JPEG.

I may be out of touch with the current legal status, but I thought .gif and .png files required websites to get a license from the patent holder(s).

73,

Bill W1AC
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Sam KS2AM
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« Reply #32 on: June 15, 2008, 11:22:55 PM »

For machine drawn schematics (and clean scans of paper schematics) a GIF or PNG file format will generally render far smaller file sizes than JPEG.

I may be out of touch with the current legal status, but I thought .gif and .png files required websites to get a license from the patent holder(s).

73,

Bill W1AC


GIF is an issue in this regard and not PNG.

"The motivation for creating the PNG format came in early 1995 when it came to light that the LZW data compression algorithm used in the GIF format had been patented by Unisys."

http://en.wikipedia.org/wiki/Portable_Network_Graphics
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Ed/KB1HYS
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« Reply #33 on: June 16, 2008, 05:53:19 AM »

Here's the last rev I did in GIF format.  I used MSPaint to edit, and MSfax/photo viewer to view. It allows me to zoom with in reason. 


* 4-250 rig.GIF (94.77 KB, 1113x1425 - viewed 367 times.)
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73 de Ed/KB1HYS
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Steve - WB3HUZ
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« Reply #34 on: June 16, 2008, 09:25:05 PM »

If the original artwork is fuzzy (a poor scan, something that was photocopied too many times, etc), then GIF will start to loose out to JPEG. But often good schematics get fuzzed up because someone used JPEG compression. You'll notice it the most around text.

I like PDF too. Still, it holds no inherent advantage over a good GIF image, given the same source. The ability to zoom/scale is a function of the viewer/reader not the image itself. With any rastered image, you will only be able to zoom in so much until the pixel resolution gets you. So if you take an appropriate source image (say a CAD of a schematic in TIFF with no compression, essentially a back and white image), and then convert it to a GIF or imbed it into a PDF, either will look just as good and the ability to zoom in and out will be identical (given the image was converted to each format with the same resolution (h-pixels x v-pixels).

On the other  hand, if  you take a true vector image and imbed or convert it to a PDF, then you can zoom in almost indefinitely (or at least up to the resolution of your computer screen or printer). But scanned images aren't vector images, so unless you are using some vector drawing program to create the schematic and then convert or imbed it to PDF, you won't have this capability.

I've attached two images. Both were created from the same source - a vector drawing. The it was converted directly to a PDF and a GIF. The files are both about the same size. But you can zoom waay in on the PDF before the edges of the drawing objects get fuzzy or blocky. Not so on the GIF. YMMV depending on the viewer used. I used the same viewer for both.




* testgif.gif (6.17 KB, 1024x768 - viewed 413 times.)
* testpdf.pdf (7.52 KB - downloaded 208 times.)
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k4kyv
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Don
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« Reply #35 on: June 16, 2008, 11:46:01 PM »

The most I could do with the .pdf was 6400% and the edges seemed to be as distinct as the 100% image.  With the .gif image I could get only two sizes, one about 75% the other one.

But I have only Acrobat Reader, which won't let me generate new .pdf files.  My scanner software will save files in .pdf format, but I have never played around with it to see if I can use it to copy other stuff to .pdf format.
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Don, K4KYV                                       AMI#5
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Steve - WB3HUZ
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« Reply #36 on: June 17, 2008, 07:13:34 AM »

Quote
With the .gif image I could get only two sizes, one about 75% the other one.

This is a function of your viewer not the GIF file itself.
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w4bfs
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more inpoot often yields more outpoot


« Reply #37 on: June 17, 2008, 12:38:12 PM »

the 6146 screen modulator has no control grid bias or dc return ... need a high value resistor to a pot to provide a way to set quiescent current ...73...John
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Beefus

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W4RFM
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« Reply #38 on: March 04, 2015, 11:37:13 AM »

Did we ever get a final drawing on this thread?  I have a boat load of 4-125a's I would like to putz around with using a simple design.
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W3RSW
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Rick & "Roosevelt"


« Reply #39 on: March 04, 2015, 12:39:02 PM »

Kb1hys' gif pic is perfectly readable on this iPad.
Might want to modify with a clamp tube, double duty, etc.

-- a new thread is an option too.
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RICK  *W3RSW*
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