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Discussion Starter · #1 ·
OK so I have a slow vertical scrolling horizontal bar. I have reconnected and disconnected everything and have determined it is coming from my cable signal over the coax.


I've read some posts and suspect maybe my cable isn't grounded well? I read about these 'ground loop isolator' things I can attach but no one (Fry's, Radio Shack, Best Buy) seem to sell them. Am I on the wrong track here? I did see one online (via Polk audio web site) for $50 which seemed high considering how tiny this thing is.


Also I saw something called a ferrite core I could apply to the cable and some inline RF filter to remove FM and ham signals?


Anyone have these problems? Know a cheap and easy solution? DO those super expensive Monster power strips clean the coax signal?


Thanks!
 

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Every Radio Shack I've seen has ground loop isolators...did you ask the person at the store? You need a fairly simple one for F-type connectors.
 

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Discussion Starter · #3 ·
Yeah I've asked at two Radio Shacks... none of the folks I spoke to understood what I was asking. Today was the closest I came with this ham radio signal filter thing. Do they sell it online from their web site?? Obviously the folks that work at the stores near me don't know much and/or they don't stock these things. Thanks!
 

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The usual workaround for ground loop problems on the cable television line is to use a 75->300 Ohm balun back-to-back with a 300->75-ohm transformer. Only certain models will work, however. I just did some quick Google searching, and this was one of the better descriptions of the process that I found.
 

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Discussion Starter · #6 ·
I have tried running it through a VCR and it currently runs through the TiVo. Whenever anything that touches that coax with the cable signal and touches my capture card I get the effect. I do not have that affect with an antenna or just VCR attached.
 

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Skriefal:


What a great idea, I wish I had thought of that! I've spent countless hours trying to solve cable ground loops, and there has been a simple solution this whole time. :)
 

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Nice, I am going to head to RatShack tonight and try this out. I have had a horizontal noise block that moves vertically from the botton to the top of my screen ever since I installed my AIW Radeon 7500 a few months ago. Hopefully this solves the problem.
 

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Discussion Starter · #9 ·
Try unplugging your tv signal and see if you still get it. I have the exact same thing but only when cable tv is attached (directly or indirectly).


Of course I solved that problem by dumping Comcrap err Comcast two weeks ago... not only is thier technical service poor, thier customer service is awful. I'd go the sattelite route but my condo faces the wrong way. I'm using an amplified antenna at the moment with decent results... few channels, but they all come in good and free.
 

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I too have a groung loop issue, which I traced to my TV cable. However, mine exhibits itself in a loud hum from my subwoofer. After doing research here on this forum (mostly the audio and hi-fi forum group) I decided to purchase this isolation transformer ($12.80) little item.

http://www.partsexpress.com/pe/showd...16262&CATID=55


I also picked up 2 of the F-Type ground blocks as well as they are only .55 each.


I will know in a week if it works. Hopefully I won't lose any signal strength and thus introduce (any more) artifacts into the cable signal.
 

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Well I tried the skriefal method of using a "75->300 Ohm balun back-to-back with a 300->75-ohm transformer" and it worked! Except that the 300->75-ohm transformer makes a crappy connection to the female end on my VCR, and sometimes I still get the noise. I wish that there was a transformer that had a damn screw-in connector on it so it would work just like the normal cable wire. Anyway, it works and it costed me about $5.
 

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Try to locate a "Xantech ground loop isolator". I found them at a local high end audio shop, but I'm sure you could find them online. Should be about $8-10. It has screw-type F-connectors on both ends. It is compatible with both digital cable and cable modem (which even the duoble balun can have trouble with).


-Jeff
 

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You can order the Xantech online from www.hometech.com for $7. They also have a store front in the San Francisco bay area (Cupertino).


They carry lots goodies for setting up a home video distribution system (Belden quad shield cable, CableVision amps and splitters, connectors, etc). Mostly it is reasonably priced, good quality, no-nonsense stuff, not the boutique stuff you will find at many AV and Home Theater stores.
 

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Discussion Starter · #14 ·
I finally solved my problem pretty easily and cheaply. I got a surge over cable the other day which concerned me, so I went out and bout the 50 buck Monster power strip which includes coax RF in/outs.


I run my cable through this, and my scrolling horizontal bar is entirely gone! No muss no fuss. Screw Comcast.
 
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