On Nov 14, 2006, at 10:48 PM, <ku8e at bellsouth.net>
<ku8e at bellsouth.net> wrote:
> I am using N1MM in the '1 - Single Card - One radio, No Sound Card
> SO2R mode. I have a 1:1 isolation transformer from Radio Shack but
> not sure how to hook it up. There is a red/black/yellow/white wire
> coming out of the transformer. I think the mic is 600ohms input on
> the radio. Any help/tips would be appreciated. Thanks.
I built a similar interface so I can use my PowerBook or my Toshiba
laptop on RTTY using CocoaModem or MMTTY (respectively).
I have the headphone output of the laptop going to two 25 ohm 1/2
watt resistors (one of each channel). I also bring the output off a
to a 600:600 ohm transformer, through a 500 ohm potentiometer, wired
as a variable resistor. (ie the variable arm is tied to one side) The
other side of the transformer hooks to the microphone input.
Adjust the output of the laptop carefully. There's usually plenty of
signal and the microphone input is very sensitive. Be careful not to
tie anything on the microphone side to ground, lest you suffer hum
from ground loops.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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