Filter removed interference...

[Savant]

While the title does seem self-explanatory, I just wanted to share my experience.

I recently changed from capturing via an ATI AIW to capturing via DV. While I had always had a bit of ground loop hum on the audio, I never considered it an issue. However with the new setup I decided to deal with it and installed an audio isolator which did the trick. The next issue was a mild amount of video interference, likely not detectable by most unless they were looking for it, and usually only noticable in dark scenes. I had analysed it and decided this was an interference issue, so I decided to invest in a high quality video isolator/filter.

I was NOT disapointed!

After receving my Jensen Model VB -1RR from the distributor, I hooked it up and the interference was gone completely. There was no signal degradation or other fallout from having the isolator in-line.

While it cost me US$100 (inclusing shipping) for this filter, it was worth the money in the long run. It's a solid piece of equipment (weighs 3/4 of a pound!) and is all metal. The specs are impressive and it has gold plated contacts to assure a positive connection.

So if there are other 'pro-sumers' out there with interference issues that want a crystal clear capture, I would suggest giving this a try.

Regards,

Savant

[lordsmurf]

My only problems come in over coax, and I've yet to see an affordable option like this device. I'm still running a low-pass hiss removal filter over all my coax captures in SoundForge, which does the trick without hurting the audio. But I'd rather have hardware when possible.

[Savant]

Have you looked at the Jensen Model VRD-1FF? After seeing this transformer I can say their product is definately high quality. I'll probably pick up one of the coax video isolators in the next month. DVWarehouse has them for US$59. (they ship internationally if I recall correctly) Other places may sell cheaper.

By the way, have you checked to make sure your cable feed is grounded BEFORE it enters your dwelling? That can be a big source of excess interference.

Regards,

Savant

[lordsmurf]

Have you looked at the Jensen Model VRD-1FF? After seeing this transformer I can say their product is definately high quality. I'll probably pick up one of the coax video isolators in the next month. DVWarehouse has them for US$59. (they ship internationally if I recall correctly) Other places may sell cheaper.

By the way, have you checked to make sure your cable feed is grounded BEFORE it enters your dwelling? That can be a big source of excess interference.

Regards,

Savant

It's satellite, and grounding is impossible in this house.

I may break down and try it, I think you or somebody else suggested it before.

This is what you are referring to, correct:
VRD-1FF 2MHz to 1300MHz CATV Isolator - F/F (Digital Cable compatible) $59.95

I'm just a bit skeptical, as I don't understand how the small device can actually help... I was hoping more for an audio purifier, not really a coax cleaner, which is what I think this device is.

It says it will remove hum bars and buzz, but what I'm getting is pure hiss, not hum or buzz (well, at least no buzz in the system I care about, the other one with buzz was a computer hardware issue that has been fixed by re-arranging PCI devices and lowering input volume).

[Savant]

Grounding doesn't just help prevent interference though. If you have a coax cable running outside and onto the roof, it is also possible it could be hit by lightning, potentially damaging your equipment. In most cases people have a splitter somewhere on the coax, and on most splitters there is usually a place you can attach a ground wire, so it's relatively easy to do. If the house itself isn't grounded, then perhaps you can look into changing that. What about a water pipe? Do you have one that runs underground where you are? If so, just attach a clamp and ground wire.

Now about the hiss on the satellite signal, I think we need to consider something here. In most cases, the satillite signal that you get from the dish to the receiver is a digital signal. Is that the case in your situation?

If so then I can't see the hiss being added to the signal on the coax. As such, that filter I suggested won't be of any help - it's designed for CATV applications. (I was assuming you had cable)

Let's take a closer look at your problem though. Hiss usually points to a 'dirty' or noisy signal.

Jensen also has a nice guide on their site that goes over troubleshooting a noise problem. You can access the PDF here.

In that guide they make a good observation...

1. If the noise is unaffected by the setting of a volume control or selector, it must be entering the signal path after that control.
2. If the noise can be eliminated by turning the volume down or selecting another input, it must be entering the signal path before that control.

This alone can often rule out a block of equipment. The key here is figuring out if the hiss is entering the signal before or after the satellite receiver. If it is entering BEFORE the receiver, then it is embedded in the signal and will need to be processed as you have been doing until you can figure out why the dish is adding his to the signal. (not aligned 100% perhaps?)

If the hiss is entering AFTER the receiver then it is likely a filter could remove the hiss, once you find out what device is causing it.

Regards,

Savant

[lordsmurf]

Looks like I got some tests to perform. Thanks.

[SatStorm]

Intersting infos...
Personally, I use RF Stoppers, you know those little magnetites for your cable. With Composite cables, those RF stoppers do miracles! They do some difference also with S-Video cables, but not so dramatic like the RCA ones.