How to fix buzzing noise from power supply

I have received reports of a buzzing sound when using my TYT TH-8600 to communicate.
Q1. Could this be a power supply causing this?
Q2. Can multiple radios be connected to the same power supply?
Q3. Is it possible to have too much power from a power supply?
I have a Pyramid PS14KX with two radios connected to it TYT TH8600 & TYT TH-9800) and normally both are not on at the same time. It supplies 270 Watts-13.8V-12 Amp constant power.
I see other power supplies with less and more power output.
The buzzing being reported, power or antenna issue?
Thank you for any advice you can provide.

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Can you do the scientific method on it and test it with a different PS? It’s normally not too much to have two radios running in monitor mode on their rigs.

Hi Jim, You mean to try a different power supply? I only have the one. I tried using the other radio I have on it and I hear a hum coming from my computer speakers. I wonder if that has anything to do with it. I do not hear it when I use my handheld unit though. My antenna is somewhat close, maybe I need to move it. Then again they power supply sits on my desk next to my computer.
I have the equipment to run an external antenna, I will do that and move the power supply as well then see how it goes, Thanks!

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If you are running a magmount antenna that is close to everything, you could be getting some RF into your power supply, I suppose. I would definitely make sure that you have a good ground plane for that magmount, if that’s what you are using. Sitting on a file cabinet or the top of the fridge is good. Lacking that, take a pizza pie tin and set it in the middle. Antennas need ground planes generally speaking, if they’re a mobile antenna.

If you are running full power, see if you have the same problem when running low power. Often times we run full power through repeaters when low power will suffice.

That hum you have could be a high CTCSS tone perhaps. You didn’t indicate whether you are running simplex or through a repeater. If the repeater doesn’t require a CTCSS tone, then make sure you aren’t transmitting one. A tone from about 192.8 Hz up through the highest of 250.3 Hz is very audible on the air and may sound like a hum to those with good ears. If you are running CTCSS and don’t need it, turn it off.

It wouldn’t hurt to check the power output of your power supply with a volt meter. Optimal output would be 13.8 volts, but you wouldn’t want much lower than 12 volts as that also would result in a power drop.

Check the amperage draw for your radios (mfg spec sheets are a good stop) and make sure your power supply is providing sufficient amps. A radio on receive only doesn’t draw much amperage, but if you transmit, depending on the power output, will draw the amps.

Can you toss one of the radios in the car with an antenna and see if you have the same hum, lacking another power supply? That might help in figuring it out.

The hum you are getting into your computer speakers is definite RF bouncing around your shack and the computer speakers have big antennas on them … wires! Those wires are picking up your stray shack RF. That’s nothing some ferrite cores can’t fix wrapped around those speaker wires. Google will help you there, if needed.

If you are using a magmount antenna in the shack, be sure to keep it away from as much electronic equipment as possible. You could damage your computer, stereo, etc. The RF could overload and cause issues. Heck, if I transmit with some handhelds near my computer, the screen might flicker and even send the computer into some crazy mode. It’s not good for them. An external antenna always is good … and keep it away from TV antennas and dishes because the same applies!

Hope that is of some help in tracking down the hum.

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Hi Chuck,
You have hit the nail on the head I believe. I nocked my power down as my repeater is only about 2 miles away and Hi power is no necessary. My power supply and my antenna sit close to my computer speakers and my antennas were not grounded.
In essence I started out all wrong just trying to get things set up and running and not planning on how I need to organize things. I have my antenna for mounting on the chimney which will get my antenna 25 feet or so up in the air. I need to “spread out” in my shack and to get my grounding rod put in the ground closer to my shack as well.
You gave great advice and pointers, thank you!

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So glad to hear, @kc3tdx! One of the tenets of amateur radio is to use the least amount of power necessary to do the job. Sure, there are the guys on HF who will run a kilowatt because they have it, but it isn’t always necessary. For instance, I run DMR through a hotspot at home (or mobile, etc.), but I really don’t need more than a few milliwatts to reach the hotspot, so I use the least amount of power, whether that’s a half-watt, a watt, etc. I have repeaters that I own that I can reach without any difficulty from home, and I always use low power through them. Running high power accomplishes nothing other than making my computer screen flash, creating RFI on other receivers in my office/shack, etc. There is an advantage to using low power! We wish you the best on getting that new hook on the air, too. Enjoy! 73

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