Guy,
There is a signal ground pin AND a shield ground pin in a standard
serial cable configuration. Some commercial cables do not even have a
shield! Make up your own cables and you will be happier.
73, Bill - K6WLM
Guy Zebrick wrote:
>
> Hey all - I found a problem, and then the solution, to a noise issue I
> discovered on 15 and 40 meters. I was doing some testing on my Pegasus the
> other night, and when I was on the dummy load, I found I had a S-5+ noise
> level on 15 and 40 meters. the other bands were quiet. Turning off the
> connected laptop PC eliminated the noise.
>
> I have an ICOM 740 (now resting in a comfortable retirement mode) right next
> to the Peg, and it was NOT effected by the noise at all.
>
> Turning on the laptop again, the noise returned to the Pegasus, BUT when I
> disconnected the serial cable, the noise went away again. I should also note
> that I have been battling a cracking noise coming into the accessory input
> when running PSK or SSTV using the speaker-out on the laptop.
>
> The noise was coming in through the cables, not 'over the air'!
>
> The solution was simple. I ran a ground wire from my grounding post on the
> back of the Peg to one of the screw terminals on back of the laptop that is
> used to secure a parallel port cable. This eliminated the crud on 15 and 40
> meters, as well as the crud on the speaker output. Seems that I may have had
> some sort of ground loop going.
>
> Funny thing is I am using a commercial RS232 cable to connect the laptop to
> the serial port on the Pegasus, so I thought the grounds would be common
> through the 9-pin cable.. but I guess not.
>
> Anyway, just wanted to share. Still think the Pegasus is one of the best
> bargains in Ham Radio along with Carl's N4PY's software.
>
> 73's
> WD5ACP
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|