Axiom Home Page Forums General Discussion Home Theater Axiom ground isolater

No more humming at Wid's house. Glad to hear that you got things fixed Rick.

Very good, Rick. Sure, it wasn't that there was something defective about the cable ground that could be corrected by changing it, but that the voltage potential beween that ground and the other ground in your system was big enough to cause a current to flow and cause hum/interference. The isolator cut the hum signal without affecting the TV signals.

Incidentally, Dr. Horse mentions a point that seems rather curious, since the claimed 1.5 GHz bandwidth would be adequate for the down-converted satellite signals. Wonder if a problem really would exist.

Hi JohnK,

The bandwidth isn't the problem with satellite signals. It's that the satellite receiver sends a voltage to the dish antenna to power the feedhorn for the dish. Axiom's ground isolator would interfere with the phantom powering of the dish's pickup.

Kind of like phantom powering of some microphones from the mike preamp in studio and remote recording.

Regards,

Alan

Thanks for the explanation, Alan. I wondered why Axiom might be limiting the sales of their excellent isolator if it could in fact pass the roughly 1 GHz incoming satellite signals. A less obvious problem, but one that still makes it unsuitable.

I have a hum I recently noticed from my bedroom SD Comcast DVR box(Pace TDC577X). I imagine the DVR has a spinning disk, but funny thing is it hums when it is OFF too. Probably totally unrelated to your issue, but since you guys were talking about humming, it reminded me of my hum.

Dave,

If you mean the whirring of the DVR's hard drive, no, that never shuts off when you turn off the DVR, only if you unplugged the unit.

If it's a ground-loop hum you are hearing through the speakers or subwoofer or the TV's speakers which is caused by the cable-TV input, that too will continue whether the DVR is on or off. That would disappear if you turned off the TV, subwoofer or AV receiver, which amplify the ground-loop.

Regards,

Alan

DVRs are notorious for spinning their disks even when "off" (standby). They can't really be off, because they need to power themselves up in order to make scheduled recordings, and also to update their guide information.