[amsat-bb] Re: usb to serial adapter woes
gerhardstein at montana.com
Thu Apr 29 21:40:09 PDT 2010
Problem reported in this thread solved. Bought and installed two
optical isolators. One in ICOM serial line and one in GS232/G5500
serial line. Rotor position now reading correctly, but there was one
more issue. Cables that I believed to be straight through were not;
they were null modem. Should have used an ohm meter right away. Tests
of pins 2 and 3 at both ends proved what the cables really were.
A warning: two null modem cables back-to-back to not make a straight
But there still are more problems with my sat system, which I will
discuss in further posts.
On 4/15/2010 6:41 PM, Larry Gerhardstein wrote:
> Jim, et. al., Thanks for the advice. However, after installing the
> USA-49WG and driver install for Windows 7 with help from Tripp Lite
> technical support, my system still does the same thing. I plug the
> serial cables to both rotor and transceiver digital interfaces and then
> to the 49WG and the same thing happens. Azimuth meter drops to zero and
> there is no control. Further it is now working worse than before, as I
> have neither control of rotor or transceiver. If measure the voltage
> between metal shields of the two cables, there is about 2 volts there.
> It sure looks like a ground loop, but where and how. I have no idea at
> this point. In 56 years a ham operator, I've never run into anything
> like this. Maybe RS232 isolators would fix this??? Seems like overkill.
> Larry W7IN
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