interference

[andystar351]

Had a lot of help from you guys over the last few days and thank you to you all.
could anyone help me just a little further with a new problem please?
i can now watch record and copy to my philips dvdr70 from any of the normal sources (dvd player, cable box, and terrestrial tv) but i am having some interference bleeding through onto the ext i use to record and watch dvds from. This background interference disappears from view when i either turn off the cable box or disconnect its co-ax input.. so i believe it is the cable tv box or the way it is connected that is the problem.
Can anyone suggest a fix for this problem as i would much rather enjoy my movies or tv from all the sources available to me rather than having to man handle the tv set half way round the room when i want to record a program or back up a DVD.
Is there anything like a supresser i can get or is there another way to kill this problem?
I am nearly there folks mainly due to your help and understanding, it just seems a shame to have to put up with a crappy picture when i have spent a truck load of money on decent kit only to fall down at the last hurdle.
any comments are most welcome.

[andystar351]

Sorry forgot to add all scarts are fully wired 21 pin, some even gold plated and the co-ax cable is brand new.

[cooljoe666]

Being fairly experienced with rigging up stuff, interference usually only accurs with a poor ground, shorted-wire, poor quality wire, coax or units being too close to power source, improper polarized power plug<<make sure all 3-prong plugs have 3 prongs and all 2 prong plugs are plugged in the right way. I have never had this issue but interference has everything to do with ground and the positive signal source being protected by radio waves. Hope this isn't too greek.

[johns0]

Sounds like you have ground loop interference and you have to isolate the problem with a ground loop isolater for your coax cable.There`s way to fix that by either buying the item or making one.

[kpkilburn]

Where do you live? I saw reference to SCART connectors, so it's Europe??? I live in Italy and my house ground is terrible (maybe "nonexistant" is a better word). It's so bad that when I touch the RCA audio/video jacks, I get a shock!

Anyway, I agree that the problem is probably poor grounding somewhere. Could be cables, earth ground for the house, antenna (if you have a power booster) ground, etc.

Some suggestions:

use the shortest possible cable lengths

keep power and signal separated (i.e., don't bunch them all together and zip tie them)

disconnect everything and start from scratch -- connect your items one-by-one and try to isolate if it's one device causing the interference or a combo of things

use only top quality switch boxes -- I went cheap and paid for it. These can cause much interference.

check your power ground, especially on multiple-socket power strips (even transformers if you use them -- I have to use 110V transformers and some are not grounded... couple that with my bad house ground and it gets ugly!!!)

[andystar351]

Ouch sounds like you have it quite bad out there.
As far as i can work out i have separated all power feeds that could have been causing the problem and have them all running from one source outlet now and the problem is still present. All scarts are highquality gold plated 21pin connections running directly to and from the equipment (no switch boxes or multiscart involved)
I have managed to isolate the problem to just being the Cable tv box as the problem doesnt occur when either this is switched off or the coax from it removed so i am now in the process of upgrading all the cabling to and from this item to see if the problem clears.
I will let you know how i get on soon
Any one out ther with any more ides?

[Matt_]

I am rearranging the video equipment in my room and, since space for the cabling is limited, was going to use some right-angle connectors in order to prevent any of the coaxial cabling from being bent into a bad/sharp angle. RadioShack sells regular right-angle connectors for around $2 and gold-plated right-angle connectors for around $4. For something like this, with regards to the quality of the signal does the gold-plating help out or is it just a gimmick ?

[andystar351]

HI matt, believe me i am no expert, the the guys on here have really helped out alot, but by asking arround and from my experience, Gold is well known to be an excellent electrical conductor, and the science behind signals travelling along gold plated equipment stems from this fact (it conducts signals aswell as it does current), but in my opinion its no good covering an item in gold if the underlying equipment is shoddy or inferior.
In other words always buy the best you can afford (without breaking the bank), and also look out for substitute (or coupled) ways of doing the same thing........looking for items which are marked up as being oxygen free de-oxygenized or low oxygen may also have the same effect and be slightly cheaper than a gold plated alternative.

[Matt_]

HI matt, believe me i am no expert, the the guys on here have really helped out alot, but by asking arround and from my experience, Gold is well known to be an excellent electrical conductor, and the science behind signals travelling along gold plated equipment stems from this fact (it conducts signals aswell as it does current), but in my opinion its no good covering an item in gold if the underlying equipment is shoddy or inferior.
In other words always buy the best you can afford (without breaking the bank), and also look out for substitute (or coupled) ways of doing the same thing........looking for items which are marked up as being oxygen free de-oxygenized or low oxygen may also have the same effect and be slightly cheaper than a gold plated alternative.

Thank you Andy for your help. I've been spending some time digesting what you said. There isn't anything at RadioShack's website (nor anything that I can think of that the salesman has said) saying that the gold plated right angle adapters (versus the regular right angle adapters) have any gold plating covering the copper wire inside their right angle adapter. If that's the case, then it sounds like all that that extra money gets you is simply gold-plated male and female screw-on ends without any added benefit in conductivity.
Plus, someone had offered the opinion that the gold plating, being thin and soft, will wear more quickly with regards to connectors that are mated and unmated often.

If you have a second, I was wondering how "oxygen free" offers an advantage in a set of cables ? When I needed to buy another set of composite and s-video cables while I was at Frys, there was huge selection with some of the products for a couple of dollars more saying that they are oxygen free.

Thank you again for your help

[andystar351]

Again the reason behind looking into oxygen free equipment is it offers a better conductivity level (working on the principal that if there is no oxygen in the cabling there can be no (or very few) impurities to interfere or distort impulses traveling along it.
IMHO if the problem you have with "getting around corners" does not give you any drop in picture or sound quality and you are not using a hi-def or rear projection set or cinema repro sound system, then using ordinary (be sure ordinary means good quality not cheap) cabling should be fine. One rule of thumb is to keep cable lenths to a minimum and with as few breaks (angle adaptors) as possible.
a few dollars well spent now could prove invaluable in the future when you upgrade your hi fi or tv set as i found to my cost when i first posted this thread around this time last year.
sorry if this has gone off topic a little its rather late so feel free to ask the same question again if i have not answered correctly or to your satisfaction.

[Matt_]

You've done a great job explaining things.
After reading through your latest reply, I felt like *I'm* the one who needed to add an "I'm sorry" -- When I read through my previous post, I hope the wording of my reply didn't sound sound like I was arguing against the important points you brought up about cabling and gold and gold's effects on conductivity.
Rather, I was thinking out loud while applying your points towards Radioshack's right angle adapters. With gold plating with cables, I was assuming that the situation is that the copper wire inside the cable and the copper wire exposed at the end of the cable is gold plated -- And so after your explanation, I was able to understand what the gold plating is doing to help out.

But with something like a right-angle adapter where the gold-plating appears to only be on the male and female screw threads, I was jumping to a conclusion about whether it would or wouldn't help out.

So what I should have said instead in my previous post was:
"I think RadioShack's gold plating appears to be on the male and female screw threads and not on the copper wire. If that is the case, does the screw thread being gold plated aide in the conduction of the signal ?"

My apologies again if my previous poorly worded reply unintentionally sounded like I, being uninformed in this mater, were trying to argue with you whose advice I had asked.

[andystar351]

Ok much simpler explanation (i think i was a little too elaborate before and may have lead you down the wrong path a little)
Gold plating and oxygen free copper cables will only be of any benefit if...... A/ you have a really long run of cable, such as between rooms or between floors which needs to be broken (as in the case of right angles etc) in order to get to its destination.
.........B/ you are using what can only be described as proffessional or "studio broadcast" quality end equipment (many thousands of dollars worth in other words)
or finally ....C/ you are faced with a very low quality picture/sound, and want to completely elliminate the cable runs as being at fault, before you throw truck loads of money at a new system.
Again it is only an opinion that gold plating and oxygen free wires help with quality if of any benefit at all, but i will say in my case spending extra money on the above most definatly helped with my previous problem.
it is my belief that in your case good quality will suffice and keep your dollars in your pocket to upgrade in the future what it becomes necessary.
hope i have helped but as you have probably guessed i dont do this often enough to get my point across precisely.
good luck anyway, and dont forget to ask around someone will always help you (they did for me on lots of occassions).[/url]

[andystar351]

This may also help you in your decision http://www.audioholics.com/techtips/audioprinciples/interconnects/cableconstruction.php