Re: [OT] K9YC's Serial Cable question

Posted by Jim Brown-10 on Jun 07, 2011; 6:35pm
URL: http://elecraft.85.s1.nabble.com/OT-K9YC-s-Serial-Cable-question-tp6450273p6450865.html

On 6/7/2011 9:06 AM, Brian - N5BCN wrote:
> For UNSHIELDED twisted pair CAT5:
> The K2 instructions use Pin 5 for the signal return lines.  Using K9YC's
> method, would I connect the return lines to the DB9 chassis, and then bond
> Pin 5 (or Pin 1, or both) to the chassis also?

Do not use pin 5 for the return, use the shell of the DB9.

> For SHIELDED twisted pair:
> The K2 instructions say to connect Pin 1 to the shield on the K2 end, leave
> the shield open on the PC end.  Using K9YC's method, would I connect the
> returns to Pin 5, shield to the DB9 chassis on both ends, and then bond Pin
> 1 and 5 to the DB9 chassis?

For shielded twisted pair, connect signal returns to pin 5, and the
shield to the DB9 shells on both ends. Do NOT bond pin 1 or pin 5 to the
chassis.

These wiring configurations are the most RFI-proof, because they prevent
pin 1 problems at both the computer and the radio.

Shielded twisted pair should be needed only when the TX antenna is VERY
close to the computer (i.e. within about 10 ft, or perhaps 20 ft and
high power.

73, Jim Brown K9YC
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