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Ground loop


columbus27

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I am get a hum out of my transmitter. When I use to work on DC audio we use to make sure the audio cable is perpendicular to power, and find a new ground. I have little experience with AC. I know that ground loop isolator could be used, but I have never used one. Does anyone have any suggestion?

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Depending on the power supply, try turning it around in the outlet.

Most of the ground loop isolators are pretty much the same. Just try one.

Different power supplies will be cleaner than others.

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How far should I get it from the computer? I was even thinking of running a completely separate ground to this outlet.

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How far should I get it from the computer? I was even thinking of running a completely separate ground to this outlet.

As far as you can, maybe even on a different circuit than the computer.

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There are many factors that can cause a hum, AC ground, Audio ground, and EMF. These are just some of them. Many years ago I took lots of classes about this. It helps to know the different ways they can acurr and that will help to solve them.

Here is some good info.

http://www.jensen-transformers.com/an/generic%20seminar.pdf

Enjoy

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You could try this "Wall Wart Tamer" which is specifically designed to eliminate the buzz from noisy wall warts:

http://n7xgshop.net/shop/product.php?id_product=19

For me, I added a choke to my audio wire (between the transmitter and computer) and make sure it's not too close to any other devices like the computer. At the start of the season I crank up an FM radio with no signal on the transmitter (but it broadcasting) and position everything in such a way to eliminate any buzz.

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I fixed 90%. I used the same 20 amp outlet but I used two different surge protectors. Then I upgraded the audio cable, and finally I move the audio cable from the back of the computer to the front.

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This may be overkill, but I don't use a wall wart to power my transmitter, Instead I use a 24v-12v DC-DC converter connected to the 24v battery in my UPS. No hum, and if we happen to have a power failure, at least there will still be Christmas music on the radio! :)

I also have the antenna mounted about 25 feet away from the transmitter, connected with coax.

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I use an adapter plugged into the cigarette lighter in my pickup truck. For my antenna I use a coat hanger drywall screwed to the aluminum skin of my mobile home. :lol:

tj

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I was doing fine until the Hamster wheel started squealing and then locked up. Now I'm transmitting via telegraph.

...Better than 2 cans and a string...

tj

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Will and TJ,

you two are just pure geniuses! I mean that coat hanger with the hook straightened gives us vertical and the bottom now the top gives us horizontal and the sides gives us both left and right diagonal radiation patterns. That way no matter how the car is aligned to your house they will get a great signal. And the exercise wheel is great. With it you where able to promote renewable energy was where the lights got its power from. And it kept the hamsters fit and trim. Them little guys get obese if they dont get enough exercise.

Sure glad we have you two around. I am just not that creative. Mind if I steal those ideas?

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