Okay, so the electrician came today. He and I are kind of chummy, so we worked together doing more troubleshooting. We connected the antenna system ground to the sub-breaker box nearby . That is the same breaker box to which the outlet for the stereo system is grounded. It made not much or no difference. Now, both should systems should be at the same ground potential, and electrician said the sub-breaker was properly grounded. That led us to believe that maybe the hum was not because of a grounding issue after all.
At this point, I'm gonna go and get a cable ground hum isolator. But for long-term purposes, the electrician and I were wondering if the antenna amplifer is making the noise. Can those things make noise that sounds similar to ground hum? Perhaps the gain on that thing is higher than it needs to be? Of course, the antenna amp's gain is not adjustable.
At this point, I'm gonna go and get a cable ground hum isolator. But for long-term purposes, the electrician and I were wondering if the antenna amplifer is making the noise. Can those things make noise that sounds similar to ground hum? Perhaps the gain on that thing is higher than it needs to be? Of course, the antenna amp's gain is not adjustable.
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Speedskater:
Thanks for that idea. I'm reply after the above post cause I didn't see your post until now. Actually, I tried removing the power injector from the TV antenna path. It did reduce the hum somewhat, but didn't eliminate it. The worst part seems to happen just when I connect the RG6 from the antenna/ant. amp. After I try the ground hum isolator, I may try another power injector, though, just to try to reduce the noise even further after.
Thanks for that idea. I'm reply after the above post cause I didn't see your post until now. Actually, I tried removing the power injector from the TV antenna path. It did reduce the hum somewhat, but didn't eliminate it. The worst part seems to happen just when I connect the RG6 from the antenna/ant. amp. After I try the ground hum isolator, I may try another power injector, though, just to try to reduce the noise even further after.
Here are a couple more.
I've used these things for years. I think the last one I bought was made by Leviton.
Amazon.com: Isolation Transformer / Ground Loop Isolator: Electronics
Amazon.com: Ancable Ground Loop Isolator,Isolation Transformer,Hum/Buzz/Noise Eliminator for Cable TV Applications: Home Audio & Theater
I've used these things for years. I think the last one I bought was made by Leviton.
Amazon.com: Isolation Transformer / Ground Loop Isolator: Electronics
Amazon.com: Ancable Ground Loop Isolator,Isolation Transformer,Hum/Buzz/Noise Eliminator for Cable TV Applications: Home Audio & Theater
The Ancable gets comparatively lousy reviews. As for the Leviton, anything with a transformer is more likely to affect the sound. So thanks, but I think I'll probably stick with the TII 220, or the Viewsonics VSIS-EU.
Still waiting for quote from a local place. Sheeesh.
Still waiting for quote from a local place. Sheeesh.
Of course. It connects to 60Hz power, also eats it. Maybe the main filter cap has crapped out.
Yes, the RF transformer will cut-out all bass below 5MHz. This IS in fact what you want: high loss at 60Hz. Your "audio" is modulated far out of the audio band to pass through antenna and cable. On either an FM or digital carrier which is not subject to everyday audio beliefs.
Okay, well, I don't claim to be an expert, that's just what I read. Besides, the transformer models in general seem to be a lot more pricey, so why not go with a model that just uses capacitors (although they're outrageously pricey too)?
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A cheap antenna isolator would be two 75/300 ohm matching transformers connected back to back.. 75 in/300 out/300 in/75 out. Connect the 300 ohm outputs together and insert inline between the antenna system and the TV..
Amazon.com: Comidox UHF VHF FM 75-300 Ohm TV Antenna Adapter Matching Transformer Coaxial Cable New 5PCS: Electronics
Amazon.com: Comidox UHF VHF FM 75-300 Ohm TV Antenna Adapter Matching Transformer Coaxial Cable New 5PCS: Electronics
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I had the same problem with multiple computers recording TV from an antenna. PCs are in 2 different rooms on different circuits so ground noise is a certainty. I found a 'galvanic isolator' from these folks that cleared up the problem. It's an RF isolation transformer and it will fix the problem
RMS Communications Inc.
Their typical customers are cable companies and MATV operators but they will sell to end users as I've bought from them twice. Last time I bought a couple years back I believe it was $25 for 3 pieces.
G²
Most baluns will not galvanically isolate which is what you need. You need a system that reads open circuit on your DVM.
This will work properly. I use them.
RMS Communications Inc.
G²
Passive preamp. A box with Neutrik RCAs, a high quality ALPS POT. That's it. And that box doesn't seem
to add any noise when only my CDP is hooked up as source.
to add any noise when only my CDP is hooked up as source.
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Using the same ground connection will help, but a ground loop is just that, it's effectively a loop aerial that picks up mains induced hum, it doesn't even need to be connected to the ground (PE)
I get that, but what I don't get is where you are proposing the loop exists at this point. If both stereo, TV and antenna system are connected to the same ground, where is the loop? In between? That's a pretty short distance of wiring, except for the antenna system. And coax is pretty low resistance, isn't it?
This is the newer version of my antenna amplifer, an Antennas Direct CDA4.
Amazon.com: 4 Port DTV Distribution Amplifier - CDA4: ANTENNAS DIRECT: Home Audio & Theater
Are these known to be noisy at all?
Mine was bought in 2012.
Amazon.com: 4 Port DTV Distribution Amplifier - CDA4: ANTENNAS DIRECT: Home Audio & Theater
Are these known to be noisy at all?
Mine was bought in 2012.
For what it's worth, here's my take on ground loops, UK style!
If an item of equipment provides a path to ground via its power cable, then many such items will provide multiple paths to ground. It is these multiple paths which constitute the ground loops.
The mains isolating transformers in items such as amplifiers will leak small alternating currents to ground. These leakage currents develop alternating voltages in the ground loops which produce 'hum' in the equipment.
As has been discussed, the effect of ground loops may be minimised by connecting all equipment grounds to one common point.
I can only suggest that there may be an item in your system which is still grounded at another, or more than one, location.
If an item of equipment provides a path to ground via its power cable, then many such items will provide multiple paths to ground. It is these multiple paths which constitute the ground loops.
The mains isolating transformers in items such as amplifiers will leak small alternating currents to ground. These leakage currents develop alternating voltages in the ground loops which produce 'hum' in the equipment.
As has been discussed, the effect of ground loops may be minimised by connecting all equipment grounds to one common point.
I can only suggest that there may be an item in your system which is still grounded at another, or more than one, location.
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I don't know anything specific about the antenna amplifier but power supply components like electrolytic capacitors do wear out and this is an inexpensive amplifier so after six years it might be time (or not).
Do you believe the problem has gotten worse over time or is the result of a recent change to components?
One way to isolate this is to disconnect the antenna lines from one component at a time (leave disconnected) and see if this has an effect, if disconnecting one item in particular greatly improves the situation that device is a candidate for an RF isolation device, at these frequencies one that uses capacitors that you can install right at the offending device should help.
Do you believe the problem has gotten worse over time or is the result of a recent change to components?
One way to isolate this is to disconnect the antenna lines from one component at a time (leave disconnected) and see if this has an effect, if disconnecting one item in particular greatly improves the situation that device is a candidate for an RF isolation device, at these frequencies one that uses capacitors that you can install right at the offending device should help.
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