Soundcard protection...

[Qwerty7]

I want to protect my soundcard from Ground Loops and static discharge while I am
decoding digital signals with my Icom R-75.
I am not an electrical whiz so making my own Audio Isolation Transformer isn't in the cards...I am much more inclined to buy somethng.
I was thinking of asking BUX.COM if they could come up with a 3.5 mm mono interface
"Isol8er". They make them for HAMS using the audio line out jack rather than the line in.
It has a built in 1:1 Isolator.
Any opinions out there ?

Thank you all,

m.m.

 

[Gene]

Protection

Mary,

Go to Radio Shack and buy two telephone pickup microphones. Only a few dollars each. They have suction cups and stick on the telephone receiver to use with an audio recorder like in the old spy or police movies. Put the suction cup of one to the suction cup of the other and tape together with electrical tape. One will act as a speaker and the other will act as a microphone. This will electrically isolate input from output.

I have used this setup for years. Only drawback is that it is monaural which should not be a problem with a scanner.

Gene

 

[Qwerty7]

Good idea...

Gene,

I am taking you up on your idea---it's original, outside the box, inexpensive and it WORKS.

Thank you,

Mary

 

[MarkEagleUSA]

There's also the RadioShack 273-1374 Audio Isolation Transformer. Wire it up to a plug and jack and you're good to go.

 

[nd5y]

You can also just buy 1 pickup coil and place it over the radio speaker. That's what I used about 25 years ago. I didn't know they were still available.
A Rigblaster or similar interface will work well. There are a few other manufacturers that
make them too. Do a search for "sound card interface" and you will find them.

 

[ka3jjz]

To be honest, I've never heard of a static discharge taking out a soundcard - it's possible, I suppose, but I don't think it's very likely.

Before you go crazy trying to find a problem that you may or may not have, use some of the suggestions Buck has on his website for eliminating the probable causes of ground loops in the first place. If you find you have one, you know what to do. Buck is a VERY respected ham and former 73 column editor, and knows a lot about his subject matter. Even though he writes about transceivers and the causes of ground loops, a great deal of that also applies to receive-only apps as well.
Personally I really don't see the need for buying an interface at all for receive-only applications; transmitting is, of course, entirely another matter.

73s and GL...Mike

 

[nd5y]

One thing you need to be aware of is that electret condenser mics require a DC voltage
to operate. These mic elements are extremely common and quipment that uses that type
of mic will have a DC voltage present on the mic jack. If you put in an isolation transformer
in the circuit, you have just put a DC short across it. If the device that supplies the voltage
to the mic doesn't have some type of over current protection, you could damage it.
Also if you plug your sound card or other device into something else that has a voltage
present to run an electret condenser mic, the same thing could happen. I put capacitors in
series with the patch cables that I use to connect my PC to the various radios to block any
DC voltage.