[1000mp] Interface/Buffer for sound card.

[Pete Smith]

Dean -- I think you can count on also needing an isolation transformer 
(600:600 ohm) on the output from your Line Out to whatever input you use on 
the radio.  This is particularly the case if you use it through a voltage 
divider to drive the microphone input on your radio, which I do for contest 
voice keying.

73, Pete N4ZR

PS -- some people have reported bad losses with the Radio Shack 
transformers -- if you encounter this Mouser.com sells transformers that do 
not have this problem, for less money.

  thatAt 10:23 AM 12/20/2004, you wrote:

>Jim,
>
>When I connect the AF Line Out from the Mark V (Rx audio) to the AF Line 
>In on the sound card, I get a heavy AC hum in the audio on the sound card. 
>I am using a patch cord with a stereo plug at both ends.  I have not 
>gotten as far as connecting the sound card back to the Patch in on the Radio.
>
>I am thinking that the 1 to 1 transformer may do the job (thank you to Rod 
>for the RS part number). I do not know the make of my sound card but it 
>came with my HP Pavilion a350n desktop computer.
>
>Thanks to everybody for your help!
>
>Dean Fewkes
>KG7MZ
>
>
>
>Jim Smith wrote:
>
>>Dean,
>>
>>Can you describe in more detail what you mean by, "...bad AC feedback 
>>loop"?  For example, are you feeding the Rx audio into the sound card and 
>>feeding the sound card line out into the patch input on the MkV?
>>
>>Jim Smith   VE7FO
>>
>>Dean Fewkes wrote:
>>
>>>I would like to use my computer's sound card for voice recording, in and 
>>>out, and other processing. When I patch my radio into the sound card I 
>>>get a bad AC feedback loop. Can somebody recommend some plans for 
>>>building an isolator? Will any 1 to 1 transformer work? Are there any 
>>>basic commercial units that will do this?
>>>
>>>Thanks for your help!
>>>
>>>I have a Mark IV Field.
>>>
>>>Dean Fewkes
>>>KG7MZ
>>>Kalama, WA
>>
>>
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