How to get super clean 3.5mm line in audio

[Anderegg]

I am having issues with static, hiss, buzz etc, on my line and mic inputs from my scanners and other sources to my PC. I bought a USB adapter with a mic in jack, but it has the same poor noise issues. I have played around with volume out levels on the devices, headphone and speaker outputs, Windows audio device levels and such, but cannot clean this up enough for my streaming. It's not overpowering, more like the noises you would get if you pulled a dirty old cassette tape out of a box from 1984 and played it on an old cruddy Walkman.

Would there be a PC audio card that would solve this problem, or external high quality device, maybe a small mixer device? Strangely enough, the noises seem most prevalent when the scanner audio/chatter ceases, like in the dead periods. No AGC or other options enabled in Windows, just a noisy input. It's very irritating, and I would like to solve it.

Thanks!

Paul

 

[bharvey2]

Paul,

It might be possible that the noise is coming from poor connections between interconnecting cables and jacks. I've run across this quite a bit. I use a product called Caig DeOxit to clean the cable plugs and jacks/inputs. I've found it to be far superior to alcohol or contact cleaner in quieting noisy connections. It might be worth a try. Good luck.

Brian
KK6DOQ

 

[Chronic]

Audio isolation

Add a simple audio isolation transformer between the scanner and the computer. or there is a commercial device sold on this site for interfacing the scanner to the computer.

Hum On Your Feed

Hum can be caused by any of the following:
A bad scanner AC power supply.
A difference in potential (ground loops) between the radio and computer.
Bad cables or a bad connection.
Other
Any or all the above.

To fix a hum problem, you can try these suggestions:
Try a new power supply or use separate 12VDC power supply for the scanner.

Best is to run all your scanners on a separate 12VDC power supply.

Most common wall wort power supplies that come with scanners are not well made, usually have little or no shielding, limited filtering, usually are only 1/2wave rectified and tend to fail.

A good 12VDC power supply is fully shielded, filtered, full wave rectified and lasts longer.

This help to avoid hum or buzz from ground loops, etc.
Make sure you have the correct type cables.
You may need to install an audio isolator (also called a ground loop isolator or an isolation transformer) between the radio and computer.

See here for: Setting up your Broadcasting Station for the correct cables and info on the audio isolator.

Setting up your Broadcasting Station - The RadioReference Wiki