Problem

[fireguy810]

Hello All,

I have a problem that I hope someone can help me with.

I recently set up a live scanner broadcast feed using a BC350C scanner, scanning low-band, high band VHF, and UHF freqs. No problems

I just switched to a BC780XLT scanner for the feed, scanning the same frequencies. The only different thing is that PL is now being used.

My problem is that since I have hooked up the BC780 I have a constant static hum on my feed. I dont hear it over the speaker on the scanner, but I've connected to the feed on two different computers and the same static hum appears.

When I switch back to the BC350, theres no hum.

Anyone have any ideas?

 

[Lexxx]

fireguy

Are you using the same audio cable between the two radios and the computer, or have you bought a second cable? To isolate the problem I'd suggest changing as little as possible to start with.

A mono cable rather than a stereo cable might solve the problem too. You don't have to buy an entirely new cable, just a stereo to mono adapter at one end should work. Unless you are doing some fancy left - right speaker streaming you shouldn't need stereo anyway.

If none of that works try grounding the 780xlt. Run a wire from some screw on the radio to a screw on the computer. The computer case (desktop type) should have at least 4 screws at the back holding on the computer outer shell. I'm assuming you have a desktop with a grounding three pronged plug, and not a two pronged laptop power supply.

Good luck,
Lexx
www.ykf.ca

 

[fireguy810]

I'm using the same exact cable. It is setup as stereo, I suppose I could try mono, but I didnt have this problem when I hook up the BC350.

 

[mlinthicum]

Make sure your using the EXT SPK jack and not the LINE OUT jack. I had the same problem when I first started broadcating with my 780.

 

[w2lie]

I can tell you from experience, Lexxx is right, use a mono connector at both ends. That completely eliminated my hum problems.

In fact, I always make my own audio cables, because if the connection is bad, I can always beat myself up!

 

[matthewtomek]

I bought a ground loop isolator from Radio Shack and it has worked for me in reducing the hum.

 

[Uplink]

This is a common problem due to the different ground potentials of your scanner and computers sound card. I use the PAC SNI-1 FILTER on my feed, works great! Just use an 1/8" mini to RCA adapter and RCA Y cables. You can get the filter for $10 Ebay, as well as Crutchfield here

 

[iMONITOR]

Hook up a ground wire from the back of the metal chassis of the scanner, to the back of the metal chassis of your computer. Or, for a quick test, hook up an RS232 serial cable between the scanner, and the computer, which will accomplish the same thing.

 

[Uplink]

Hook up a ground wire from the back of the metal chassis of the scanner, to the back of the metal chassis of your computer. Or, for a quick test, hook up an RS232 serial cable between the scanner, and the computer, which will accomplish the same thing.

That was what I tried at first, in my case it didn't help. Filter works awsome and no DC can get through.