Anyone find a VGA Extender that WORKS????

mikefellh

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I already use several extenders in the auditorium I run.

(Extenders being a pair of devices, one that converts a standard signal to Cat5-6 networking cable to another device that converts it back to the original standard, for instance HDMI-Cat5e-HDMI, for extending the signal over a much longer length than is allowed by the original specification.)

I currently have a raceway with six 30m (100feet) UTP Cat6 cables from the BOH projection booth to the FOH lectern, and I have been running:
- HDMI extender (up from lectern)
- USB extender (down to FOH)
- 4x XLR extender (down to FOH)
- ethernet cable (down to an auditorium access point)

For the two remaining lines I want to have TWO VGA extenders (one low res (1024x768) to control the booth computer FOH, and the other (1920x1200) to feed the podium monitor with the projector signal).

The ones I have tried out have been poor and fiddly...you have to adjust the gain and peak on the receiver to compensate for the length of Cat cable...all the other extenders I've bought just work with no adjustment or issues. The issues I've been having with the VGA extender is poor picture, from softness to streaking to blotches (there would be NO WAY this would be good for projection for instance, and will be giving them 1-2 stars on my planned review on the reseller's site as well as returning them).

You may say it's because the VGA signal is analog and the rest are digital, except the XLR extender is analog and is in the same raceway and has just been plug and play.

So my question is, has anyone found a decent VGA extender, that doesn't cost a fortune, that actually works and gives a decent image?
 

mikefellh

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Decided to throw money at the problem and ordered a StarTech brand VGA extender to try out. Will let you know after tomorrow (the HDMI extender I already use is a StarTech brand and it's a decent device). I love free same day shipping!
 

ruinexplorer

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Unfortunately, I always go with more expensive equipment, such as Extron. At only 30m, do you need an extender for VGA? I would often use 5-wire RGBHV. I would also use a VGA cable of that length, but sometimes it required boosting the signal before that run, especially for higher resolution. With 5-wire, I never had to boost the signal.
 

mikefellh

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Thank you for taking the time to reply...

Unfortunately, I always go with more expensive equipment, such as Extron.
I had a look at the Extron VGA extender on Amazon, and it's roughly the same price as the one I bought in the end. I already had a StarTech HDMI to the HDBaseT connector on our projector which works very well, so I trust StarTech. And while still not as good as the output from the HDMI extender, it's good enough for the FOH monitor and the 10" lectern monitor that's attached to the VGA extender, and definitely better than the original one I had!


At only 30m, do you need an extender for VGA? I would often use 5-wire RGBHV. I would also use a VGA cable of that length, but sometimes it required boosting the signal before that run, especially for higher resolution. With 5-wire, I never had to boost the signal.
I have done long runs with VGA in the past, but as I explained above last summer we had a raceway with six Cat6 cables installed for not only VGA and HDMI use, but also USB and Audio, and the only issues have been with the VGA extender.
 

EdSavoie

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The problem with VGA extenders is that (at least the ones I've seen) manipulate the analog signal directly rather than try to convert it to a digital signal and reconstruct it at the other end.

This means that at the end of the day, you're still praying that the signal doesn't get mangled by the time you've reached the other end. The amount of inconsistent Tint and noise I've gotten off of units like these looks terrible.
 

jdenora

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Yes, there is a VGA extender that actually works. It stretches from Bigfoot's cave to Amelia Earhart's airplane. In other words, no, I've never seen one that actually works the way you expect. They are all a compromise of one kind or another.
 

ruinexplorer

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I have done long runs with VGA in the past, but as I explained above last summer we had a raceway with six Cat6 cables installed for not only VGA and HDMI use, but also USB and Audio, and the only issues have been with the VGA extender.
I guess that I misunderstood that you could not add cable to the raceway. Have you tried using a VGA to HDBaseT as an extender? I only suggest that as many of the VGA extenders that I had more success did not use Cat6, but instead used 5 or 5e. When attempting to use them with 6, you will run into issues as that is not what they are designed for. Yes, there are ones that are designed for 6, which may increase skew if the signal is not being translated to something different or the extender does not have skew correction. Here's an article which may help you understand skew and how it can be corrected.

Other than that, how did your new extender work?
 

FMEng

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Use RealVNC to control the booth computer. It is a good little piece of software and you won't need any dedicated video or keyboard/mouse path.
 

mikefellh

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I guess that I misunderstood that you could not add cable to the raceway. Have you tried using a VGA to HDBaseT as an extender? I only suggest that as many of the VGA extenders that I had more success did not use Cat6, but instead used 5 or 5e. When attempting to use them with 6, you will run into issues as that is not what they are designed for. Yes, there are ones that are designed for 6, which may increase skew if the signal is not being translated to something different or the extender does not have skew correction. Here's an article which may help you understand skew and how it can be corrected.

Other than that, how did your new extender work?
Gives me food for thought...unfortunately they ran Cat6 cables (even though it was specified 5e), and it would be close to $1000 to change the two cables that are used for VGA since it would require scaffolding, etc. You can see in the first attachment how the Cat cables are run in the booth, and that location is 18 feet up on the auditorium side. In the second image you can see the smearing I'm getting, but since those VGA monitors are just for monitoring and selecting fines, the poor image quality is not an issue (but still a disappointment).

The video from FOH that feeds the BOH projector though is HDMI to HDBaseT, and at times I've used a VGA-HDMI converter when a presenter comes with a VGA laptop.

IMG_20180128_135512.jpg
IMG_20180128_141817.jpg


Use RealVNC to control the booth computer. It is a good little piece of software and you won't need any dedicated video or keyboard/mouse path.
Problem with our auditorium is it's a camera club with over 100 members connecting to our network at times; although I could set up a private network to do what you say, I much prefer controlling the computer with a dedicated keyboard/mouse/monitor combination...I also use a dedicated wireless computer remote with laser pointer for presenters to control their presentations. What I may do is set up a guest SSID on the router that's closest to the lectern for guest presenters to use.
 
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ruinexplorer

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Thanks for the clarification. I was imagining a bigger raceway for sure.

Is this image the one from your new Star Tech extender?
 

mikefellh

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Thanks for the clarification. I was imagining a bigger raceway for sure.

Is this image the one from your new Star Tech extender?
I admit when I had arranged for the cable installation I also imagined it would be a wider raceway for future expansion!

As for the smeared image, yes...but the VGA extender I had before was MUCH WORSE!

One thing I didn't ask is if they wired the jacks in "A" or "B" configuration...all the Cat cables I've been using have been "B"s...will have to lift the covers off the jacks to check.
 

ruinexplorer

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The wiring configuration may or may not have anything to do with it. From what this looks like to me, instead of the color being skewed (the Extron paper I cited previously), this looks more like jitter. Old analog TV days, we might say that the image was ghosting. There are a couple of reasons this might happen. This article might help you figure it out. It may be as easy as making sure that your cables have shielding when they are close to power. On the other hand, it could be due to the delay in some of the signal due to it being Cat6 instead of Cat5.
 
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FMEng

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Jacks wired A or B makes absolutely no difference. VGA extenders are the one instance where Cat 6 is worse than Cat 5. Belden and Mohawk make special, low skew cables for use with VGA extenders. Normal Cat 5 cables have twisted pairs that vary in length due to different rates of twist. The twist is varied to reduce crosstalk. Because the length is different, the signals on each pair are delayed differently, which appears as color skew. Cat 6 twist rates are staggered even more, which makes VGA look even worse. The special cable uses the same twist rate for all four pairs, which is ideal for video, but worthless for ethernet.
 

mikefellh

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You've given me a lot to think about, and wished I knew before. Kicking myself in the butt too for not insisting on Cat5e as I stated in the wiring quote (guess the network cable installers thought I didn't know what I wanted requesting an older/slower cable standard).

I want to go over everything first, and as a last resort I'll order a skew corrector like this:


or


Of course I appreciate if anyone has any advice on this reply. Would an image like the following help me diagnose the skewing issue:
 
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venuetech

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The color bar image shows the correct alignment. If one or more colors were skewed they would not be in vertical alignment with the others. You can use this display to make the necessary adjustments.
 

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