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geekhack Community => Other Geeky Stuff => Topic started by: dantan on Thu, 09 March 2017, 23:05:25

Title: How to extend VGA and DVI-D cables on the cheap
Post by: dantan on Thu, 09 March 2017, 23:05:25
hey guys

I have a monitor that takes DVI-D and VGA.
 I want to put about 10 ft away from my pc.
I have many 6ft DVI-D and VGA cables and a few adapters and attachments.

I'm wondering if I can just plug these cables into each other and my distant monitor will be able to work the same as if it had been placed closed to my pc in a standard multiple monitor array?
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: tp4tissue on Thu, 09 March 2017, 23:58:23
/head scratch..

hahaha, i can't believe this is a serious question.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: dantan on Fri, 10 March 2017, 00:34:14
It is serious. I've never seen anyone do it before. But I can't find 10ft vga cable or dvi cable at a reasonable price, and I have all these old and shorter cables. I just dunno if they will work so I'm asking.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: tp4tissue on Fri, 10 March 2017, 01:52:03
the  dvi can go into vga.

the other way around might not work with some newer monitors which don't accept dvi-i or dvi a


But this is weird that you'd need to do this, what do you consider reasonable price for a cable ?
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: Mechboards on Fri, 10 March 2017, 03:04:00
3M/5M/10M cables are available here - http://www.ebay.co.uk/itm/like/151215486303?lpid=122&chn=ps&adgroupid=40208335658&rlsatarget=pla-276891047667&adtype=pla&poi=&googleloc=1007265&device=c&campaignid=738217568&crdt=0
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: fohat.digs on Fri, 10 March 2017, 07:30:18
Socket plugs and additional length all degrade your signal.

If you have the pieces on hand, then ganging them together and testing it yourself is a trivial exercise.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: dantan on Fri, 10 March 2017, 08:29:19
Socket plugs and additional length all degrade your signal.

If you have the pieces on hand, then ganging them together and testing it yourself is a trivial exercise.

I have a bunch of plugs, but all feature 1 female, 1 male. IE the standard adapters. To run extensions I'll need to buy F to F. But extensions are not very expensive. Just the waiting time.

Compared with full 10ft or longer cables, which in my country plus shipping, easily tops $30 plus lots of waiting time from China or UK. Don't know why so many cable and parts sellers are in UK, like what Mechboards suggested.

no matter what I do, it can't be done in under 1 week unless I go to a bricks and mortar shop and pay through my nose. Seems as though whatever price can be found on the internet, the bricks and mortar will double or triple that. :eek:
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: fohat.digs on Fri, 10 March 2017, 11:33:02

I have a bunch of plugs, but all feature 1 female, 1 male. IE the standard adapters. To run extensions I'll need to buy F to F.


I have run into that many times. Accessories such as cables are high-profit items in stores because when you need it, you need it, and it is not an optional purchase while you are standing there.

I have a large bag where I toss all my obsolete cables, and I go into it from time to time. But yes, male-male or female-female cables tend to be far less common than extensions.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: zeltner on Fri, 10 March 2017, 12:19:02
I've seen VGA extended for 100+ feet using cat5/VGA adapters
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: tp4tissue on Fri, 10 March 2017, 14:58:47
I've seen VGA extended for 100+ feet using cat5/VGA adapters

you can do it with solid cables.. this won't work for stranded..
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: FrostyToast on Fri, 10 March 2017, 15:12:55
DVI is digital meaning it can be adapted to something that makes sense like Hdmi or DisplayPort.
Now if your video out doesn't have either of those then the real question should be, "which graphics card should I buy"  :))
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: dantan on Fri, 10 March 2017, 15:13:35
I don't need 100 ft. I just need 10 ft. So if I buy a Female to Female adapter over the internet and hook that up with a couple of my many VGA cables, that is likely to work with minimal signal problems?

Was really frustrated when I realized I could get a brand new 17" flatscreen for less than the cost of a 10ft cable. Even worse, many shops are happy to sell you their old 17" stock, but very few stock that 10ft cable so getting it in a reasonable time is not likely.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: tp4tissue on Fri, 10 March 2017, 15:13:59
DVI is digital meaning it can be adapted to something that makes sense like Hdmi or DisplayPort.
Now if your video out doesn't have either of those then the real question should be, "which graphics card should I buy"  :))

there's dvi- i and dvi - a    which are analogue, and use the same pins.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: FrostyToast on Fri, 10 March 2017, 15:16:31
DVI is digital meaning it can be adapted to something that makes sense like Hdmi or DisplayPort.
Now if your video out doesn't have either of those then the real question should be, "which graphics card should I buy"  :))

there's dvi- i and dvi - a    which are analogue, and use the same pins.

But op says monitor is DVI D.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: tp4tissue on Fri, 10 March 2017, 15:24:42
DVI is digital meaning it can be adapted to something that makes sense like Hdmi or DisplayPort.
Now if your video out doesn't have either of those then the real question should be, "which graphics card should I buy"  :))

there's dvi- i and dvi - a    which are analogue, and use the same pins.

But op says monitor is DVI D.

it MAY or May not support dvi i or dvi a, which is why i replied originally that this is not a good idea..

That said, it MIGHT support it,   so he could try using one of those adapters that come with graphics cards.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: FrostyToast on Fri, 10 March 2017, 22:16:58
DVI is digital meaning it can be adapted to something that makes sense like Hdmi or DisplayPort.
Now if your video out doesn't have either of those then the real question should be, "which graphics card should I buy"  :))

there's dvi- i and dvi - a    which are analogue, and use the same pins.

But op says monitor is DVI D.

it MAY or May not support dvi i or dvi a, which is why i replied originally that this is not a good idea..

That said, it MIGHT support it,   so he could try using one of those adapters that come with graphics cards.

Adapting digital DVI to other digital standards shouldn't be a problem. I've converted display port to DVI before without a converter. It would only be a problem if he went between analogue and digital.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: Leslieann on Fri, 10 March 2017, 23:46:36
Just get some cheap 10 foot cables off Ebay, that's what I did.
10 foot isn't a problem even with cheap ones.

However, stay away from cheap display port to dvi cables (and probably adapters), they are nothing but trouble. Spec says they can do well over  100 feet, I had problems with 15 foot cables, and then one entirely died on me after a few weeks. The refresh rate was clipping, causing monitors to go blank, I even spoke to my video card manufacturer and it stumped them to the point of offering to test it for me to see if the card was going bad before finally figuring out the problem.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: FrostyToast on Fri, 10 March 2017, 23:51:35
I haven't had any problems with my adapter which I used for a good few years. If I recall it was from Startech.
Cheap no name brand stuff will always mess things up, but that wouldn't mean something quality won't work either.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: dantan on Sat, 11 March 2017, 01:33:59
Just great... tried out my monitor today, and it looked terrible. Hard to explain what the problem is, and if monitor is turned off you can't see it. Kind of like there are lots of pixels in there. I don't mean dead pixels, more like monitor has a very light case of measles or freckles.

left it in my office. Not going back till Monday, sigh. And my brother printer is mysteriously unable to install on my windows 10 computer. It just refuses to recognize the usb thing.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: cribbit on Tue, 14 March 2017, 13:18:55
Just great... tried out my monitor today, and it looked terrible. Hard to explain what the problem is, and if monitor is turned off you can't see it. Kind of like there are lots of pixels in there. I don't mean dead pixels, more like monitor has a very light case of measles or freckles.

left it in my office. Not going back till Monday, sigh. And my brother printer is mysteriously unable to install on my windows 10 computer. It just refuses to recognize the usb thing.

Printers are devilspawn.

For the monitor, make sure you're using DVI (not VGA) and buy a longer cable. DVI is digital signal so it doesn't degrade over distance, it either works or it doesn't. VGA is analog so it can decay.

Or buy an HDMI -> DVI cable from Amazon, 10ft for like $4, and use the HDMI port on your computer. HDMI and DVI are the same pins on a different plug so there's no actual conversion there.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: Findecanor on Tue, 14 March 2017, 15:56:54
That digital signals won't degrade over a distance is a myth. They do. Every wire has some inherent impedance and capacitance, which gets worse with distance.
You just won't see a linear degradation - you would get the wrong bits, which in HDMI/DVI-D images will look like sparkling in the image.

Once upon a time when 1080p HDTV was just being introduced, there were cheaper HDMI cables around rated for only 720p that had this problem when used with 1080p signals. They had been made with thinner wires.
DVI-D and HDMI have the same signalling up to at least 1920×1080 (without DRM and crap).
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: cribbit on Tue, 14 March 2017, 16:05:48
That digital signals won't degrade over a distance is a myth. They do. Every wire has some inherent impedance and capacitance, which gets worse with distance.
You just won't see a linear degradation - you would get the wrong bits, which in HDMI/DVI-D images will look like sparkling in the image.

Once upon a time when 1080p HDTV was just being introduced, there were cheaper HDMI cables around rated for only 720p that had this problem when used with 1080p signals. They had been made with thinner wires.
DVI-D and HDMI have the same signalling up to at least 1920×1080 (without DRM and crap).

Sorry, I should have been more clear about that. When I say "works or doesn't", my definition of "doesn't work" is any sort of artifacting or "wrong bits" as you say. Whereas an analog signal will get fuzzier, meaning that it can be hard to tell when you have 100% quality or just 90% quality.
Title: Re: How to extend VGA and DVI-D cables on the cheap
Post by: robertdane101 on Tue, 04 April 2017, 01:38:16
I think you should try it. Besides if you are spending money on buying two F-F converters why not just buy a new 10ft cable?
A few places are:
Startech: https://www.startech.com/ca/Cables/Audio-Video/VGA-Cables/10-ft-VGA-Video-Monitor-Cable-DB15-Male-Male~MXT101MM10 (https://www.startech.com/ca/Cables/Audio-Video/VGA-Cables/10-ft-VGA-Video-Monitor-Cable-DB15-Male-Male~MXT101MM10)
<SNIP>

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