ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: Cat 5 Balun issues  (Read 11224 times)

drewgandy

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 588
    • http://gandymethod.com
Cat 5 Balun issues
« on: December 22, 2010, 10:34:22 pm »

I've recently installed Niles C5 passive baluns in 2 different jobs and have had ghosting issues in both.  The first one is the HDDA model which is for component video.  The run is on the order of 25 feet on Category 6 cable.  Severe ghosting (duplicate image shifted slightly to the right) that is significantly better when I bypass the DA amp just ahead of it but the ghost is still there.  The other job is a 110 foot run to a projector with the VGA model.  In this case I initially tested the Cat6 run with a battery powered laptop.  Macbook Pro ->  displayport/VGA adaptor ->short VGA cable -> balun ->Cat 6 cable -> short VGA cable to the projector.  Suspecting the laptop (macbook pro 13) may need a little "help" I added a VGA distribution amp ahead of the balun but still the same ghosting.  Anybody have trouble with passive baluns in this way?  

drew
Logged

Mac Kerr

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 10223
Re: Cat 5 Balun issues
« Reply #1 on: December 22, 2010, 11:03:31 pm »

drewgandy wrote on Wed, 22 December 2010 22:34

I've recently installed Niles C5 passive baluns in 2 different jobs and have had ghosting issues in both.  The first one is the HDDA model which is for component video.


Are you using low skew category cable?

Mac
Logged

drewgandy

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 588
    • http://gandymethod.com
Re: Cat 5 Balun issues
« Reply #2 on: December 22, 2010, 11:28:14 pm »

Mac Kerr wrote on Wed, 22 December 2010 22:03

drewgandy wrote on Wed, 22 December 2010 22:34

I've recently installed Niles C5 passive baluns in 2 different jobs and have had ghosting issues in both.  The first one is the HDDA model which is for component video.


Are you using low skew category cable?

Mac

I've not noticed mention of skew (or low skew) on any of the baluns I've dealt with so far.  If it meets the Cat 5/6 spec it should meet the Cat 5/6 spec (including skew), right?  

The Cat 6 is this   http://www.parts-express.com/pe/showdetl.cfm?Partnumber=101- 037.  The component baluns were also tested with a coil of cat 5 that I happened to have but the ghosting seemed to be exactly the same.  

drew

Update:
I see that skew is not typically a troublesome issue with data but can be with video.   If I understand it correctly, skew is a very short amount of delay between conductor pairs that mucks with sync or what might be called convergence?  What I'm seeing with the component seems like reflections of the same image on all three colors, not a mis sync of the colors.  The VGA issue I'm not so sure about.  But both runs are relatively short and skew seems to be an issue at the longer end of things.  ?
Logged

Mac Kerr

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 10223
Re: Cat 5 Balun issues
« Reply #3 on: December 22, 2010, 11:42:31 pm »

drewgandy wrote on Wed, 22 December 2010 23:28

Mac Kerr wrote on Wed, 22 December 2010 22:03

drewgandy wrote on Wed, 22 December 2010 22:34

I've recently installed Niles C5 passive baluns in 2 different jobs and have had ghosting issues in both.  The first one is the HDDA model which is for component video.


Are you using low skew category cable?

Mac

I've not noticed mention of skew (or low skew) on any of the baluns I've dealt with so far.  If it meets the Cat 5/6 spec it should meet the Cat 5/6 spec (including skew), right?  

The Cat 6 is this  http://www.parts-express.com/pe/showdetl.cfm?Partnumber=101- 037.  The component baluns were also tested with a coil of cat 5 that I happened to have but the ghosting seemed to be exactly the same.  

drew


You should be using low skew cable with component video over passive baluns.

Mac
Logged

chris fletchall

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 61
Re: Cat 5 Balun issues
« Reply #4 on: January 02, 2011, 10:39:51 pm »

I have just had the same issue with intellix baluns in a whole house distribution. The ghosting was horrible. On a Direct TV guide it was as whole letter off.

We spent two weeks on the phone with support from Niles, Intellix and Vanco before some one said try an active balun.


The fix that we found was Elan's HD baluns

http://www.elanhomesystems.com/productdetail.asp?id=95

They have a gain and footage control that cleaned up the ghosting. Cost a little bit more and they need power but a happy customer and a good picture was worth it to us.

Logged

Karl P(eterson)

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1637
Re: Cat 5 Balun issues
« Reply #5 on: January 03, 2011, 10:14:51 am »

If your going to bring up active baluns in a professional forum, you should probably mention that magenta research offers some of the best, and the pricing isn't terrible either. Additionally, there are very good products which can be had from the usual suspects (Extron, Kramer, Etc) as well as some of the smaller guys (I own dozens of the SP Controls CatLink Products).

Nonetheless, I usually go straight for active baluns these days due to similar issues.

Karl P
Logged
TeamLeader.Technical Systems - CCH

drewgandy

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 588
    • http://gandymethod.com
Re: Cat 5 Balun issues
« Reply #6 on: January 22, 2011, 10:30:54 pm »

Karl P(eterson) wrote on Mon, 03 January 2011 09:14


Nonetheless, I usually go straight for active baluns these days due to similar issues.

Karl P


Here's the follow up to my balun issues:
First of all, thanks to Mac for the recommendation.  I spent some time educating my ignorance about cable skew and other balun stuff.  But, skew was not the problem on the very short component video run and Key Digital tech support confirmed my suspicion that skew would not be a problem on a run so short.  I ended up putting a Key Digital active balun in that job and solved the problem.  On the other job with the VGA baluns I put in a Gefen active balun as it only required power at the send end which was better for that particular arrangement.  That room won't be in actual use for another month or 2 so I have yet to see if there are other issues but my initial test looked pretty good; ghosting issues were gone.  
I can't recommend the Niles baluns as they have no skew correction and on top of that seem to have some impedance matching problems.  Further, despite their availability on the phone, they did not mention the importance of low skew cable (which certainly could be an issue with their completely passive baluns) and ultimately they did not have real solutions to my issues.  They straight out said that their products simply "might not work".  I understand that caveat emptor is the risk we take with ANY product but they didn't seem to know or even want to try to figure it why these weren't working.  

drew
Logged
Pages: [1]   Go Up
 

Page created in 0.027 seconds with 15 queries.