Receive Drop when on Power Supply

[Trondyne]

Hi all,

When I run my President Richard on my power supply I have discovered that weak signals become very hard to hear... There doesn't seem to be any obvious noise but the sound of those signals almost drops out.. When connected to a batter however the audio is far cleaner and easy to understand...

Can anyone tell me what this means?

Thanks

 

[AK9R]

One possible answer is that your power supply is generating a lot of RF and you are hearing that noise in your radio.

What power supply are you using?

 

[Trondyne]

No actual change/increase of background noise is noticeable but the low signal audio drops down from what would be say a 4 by 5 to a 1 by 5... The power supply is just a low cost variable output unit that goes from around 8 to 15 volts... I had tried a noise filter but it didn't seem to help although to be sure I need to recheck everything... All I can say for sure now is that when running the radio off of a battery it is far easier to hear low audio...

Thanks

 

[mmckenna]

How is your system grounded?

I'm wondering if you are grounding through the power supply and causing issues. Might be a bad coax connector that finally finds a path to ground through the power supply.

Or, as stated above, just a noisy power supply. What brand/model is it?

 

[Trondyne]

There is no ground other than the power path to the supply... I have no way to ground in a conventional sense like a ground spike outside... The power supply is a common no name unit...or at least I do not know the name, I can check later though. I can try grounding the radio to the power supply chassis again, the last time it seemed to introduce more noise from the power line... Running off of a battery makes the low audio much clearer, although the noise floor doesn't change as far as I can tell, which I discovered last night.

Thanks

 

[mmckenna]

There is no ground other than the power path to the supply... I have no way to ground in a conventional sense like a ground spike outside... The power supply is a common no name unit...or at least I do not know the name, I can check later though. I can try grounding the radio to the power supply chassis again, the last time it seemed to introduce more noise from the power line... Running off of a battery makes the low audio much clearer, although the noise floor doesn't change as far as I can tell, which I discovered last night.

Thanks

OK.
As others have said, power supplies can create noise. That RF noise may well be outside the CB band, and it won't show up on your radio, but still be loud enough to overwhelm the receiver. Using the clean power from the battery would reinforce this.

The grounding thing is a possibility, but that's more difficult to solve.

 

[WA0CBW]

Did you check the voltage output from the power supply with a voltmeter?
BB

 

[wtp]

connection with the battery giving you a better RF ground ?

 

[Trondyne]

Voltage appears correct on the PS... I suspect it's an RF noise thing but not 100% sure there isn't a ground issue... On an aside does anyone know if on these kinds of radios that say they run on 13.8vdc how high a voltage is safe? If higher voltage is okay I could run a 4S Lipo battery I have that would last much longer than my 3S pack... The 4S pack fully charged peaks at 16.8 volts... I'll be experimenting with all thanks.

Thanks

 

[Trondyne]

Just an update for this for anyone interested... I have found in testing that the radio is picking up all kinds of RF interference from this power supply and other things.. Even when not connected but turning on the power supply the noise level or noise floor goes up on the radio... Other devices in the room also can be heard even when running the radio off a battery...