Please help I can't get rid of the static!

Static still!!!

Hello I've had this feed up and running and I have tried everything to get the static hum out of my feed. I am using a pro-2096 on a DC power supply that goes to my ups. From my antenna I have a iso-max isolator and some cable looped up. from the scanner to the laptop mic port I have 3.5mm filter and the duel audio Jacks with only the white hooked up for mono. I really would like my audio to be crystal clear when nothing is coming across the air if anyone has any suggestions please feel free to help. It's madison County Fire and ems in Madison County Indiana. Thanks!

Was going to ask if your power supply

was the switching type. But it really looks like there's a ground/shield not connected.
You mention that you're using white for mono, but is the shield totally connected at both ends?

Try another power supply or using battery power. Maybe the power supply is picking up interference from other nearby wires... try rerouting the PS wire(s). Good luck.

The real question is how and where have you made the audio connection.

If your using the speaker output of the scanner, stop.

You might have to install a capacitor in series with the high audio wire to block any DC voltage that might be on the line your using.

I would try using the earphone jack. That way your not getting a real high level going into your computer.

The next question is what port are you trying to feed the audio into the computer with? Hope it's not the mic input. Your much better off using the line input. That way the computer can handle a much higher audio level input.

My guess is that you over driving the audio level into the computer. This just drives up the background noise levels. Think this might be where your getting all the hum and static from. It's called compressing the audio. This is a common problem when agencies try using radio interoperability gateways and don't set the audio gains correctly.

Let the group know how you make out and what you did to resolve thew problem.

I am using the earphone jack on the scanner and the mic port on the computer since it is a laptop I don't have any other option right now. That has to be the problem because I have tried several different options and end up with the same sound

are you looking for silence in the stream during inactivity? is that it? I'm not sure what audio streaming software you are using, but i'd look at a VOX / threshold setting in it.

is it feed 2318? I just listened to about 15 seconds of it, and I didn't immediately think "oh christ, thats a lot of overpowering static", and the audio seems to clip nicely.

Yes I know it's not horrible but I hear all of these other feeds that are almost silent during inactivity and would like the same. I am using the K1PGV's scanner cast rr edition I got off of here.

Hum loops - insert an 1:1 audio transformer in the cable from the scanner to the computer - have no direct DC connection between the two including through the mains power. This may mean having to get an isolated power supply for the laptop.

I wouldn't have answered this if I had seen all the answers to your other identical post.

Monitor Record Audio on PC

When using a headphone / speaker output from the scanner and feeding that signal into a mic input, it is tricky getting the levels set correctly. You don't need to have the volume of the scanner set very high. I liked having my mic input level set to 50% and then set the volume for good dynamic range.

What you need to do is monitor the audio before it is being streamed out. I used a digital meter to see the audio level and that helped a lot. The one I use is from Darkwood.

But, the 1:1 isolation transformer AND the correct load on the scanner' s audio will go a long way in making the audio sound good. You may even need an attenuator in the audio going to the computer.

If the laptop has a 'line in' try that before all the other fixes. Mic inputs tend to amplify the signal a lot more. Also be sure to use the headphone out jack on the scanner, not the external speaker jack without an adapter for speaker to low level rca jacks. I have actually had ground loop isolators cause more hum!! Here's another one if you haven't tried it. To rule out the laptop power supply, run it on battery only and see what happens.
Every configuration is different.

Chuck

Duplicate threads merged.

Please don't create multiple threads asking the same question, thanks.

Here's what worked for me on my feed: Wauconda Police, Lake County Sheriff and Quad 3 Fire. I have a Pro-197 hooked to the line input of a desktop via the external speaker jack on the back (left side), and a PRO-51 hooked up via the headphone jack (right side).


1. Get a good audio meter such as the one already mentioned; I like this one from Orban: ORBAN Loudness Meter

2. Since you're using the mic input, open Windows recording control and turn off any mic boost, if it's on.

3. Set your input level fairly low to minimize input noise, and adjust the volume on your scanner, while observing the meter, to get to no more than -3 db DFS (brief peaks to 0db are okay).

4. Download an archive file from your feed when you know there's a good bit of activity and view the waveform in a program such as Audacity. You'll be able to tell if you're clipping or not loud enough, and you can see the noise level in between transmissions.

Hope that helps!

There are a lot of good points made and help provided here. Great thread!

rdailey42, if you are still not happy after getting your audio levels set and trying everything described here, you might consider getting a USB audio interface for your PC. USB audio interfaces can be obtained rather cheaply on Amazon and eBay. Such interfaces do not replace getting your signal levels correct, but they do help simplify the process because you aren't dealing with a microphone input. Mic inputs can be very cranky. Your feed sounds pretty good using a mic input!

Which Iso-Max are you using? To remove ground loop hum, it needs to be in the audio signal chain between the scanner and the computer.

As for my feeds, each one uses a PRO-197 with audio coming from the external speaker jack on the back(these units do not have a line out, and the headphone jack is as hot as the external speaker jack). My setup works like this:

Scanner audio --> Audio compressor --> Isolation transformer --> USB audio interface --> Computer

The audio signal strength in my feeds varies quite widely between agencies, so I use the audio compressor to help level out the audio signal strength.

If, after getting your signal levels set, you still aren't happy with the noise on the feed between transmissions, you'll need some sort of a noise gate. A noise gate is a device, either in standalone hardware or in computer software, which allows the audio signal through whenever the signal strength exceeds a threshold set by the user. The compressor I use has noise gate functionality, and I use it to keep the feed quiet between audio transmissions.

Keep us posted on your progress!