Shielded wire for GPS signal?

TX7A · #1 10-16-2011, 01:20 PM

I'm wiring in a source select switch for GPS to A/P. Do the signal wires from GPS (lets say a 496) need to be shielded?

Thanks

rleffler · #2 10-16-2011, 02:18 PM

Quote:

Originally Posted by TX7A

I'm wiring in a source select switch for GPS to A/P. Do the signal wires from GPS (lets say a 496) need to be shielded?

Thanks

All RS-232 and RS-422 lines should be shielded. Be sure only to ground the shield at one end and don't use the shield for a signal line.

Walt · #3 10-16-2011, 02:55 PM

I agree they "should" be, but with such short runs usually found behind the typical RV panel, I really don't think its necessary. I have seen and run many single wire RS232 lines in RV's, never had a problem.

rv9aviator · #4 10-16-2011, 03:09 PM

Mine isn't but it is only about 10 inches long. Could that cause any kind of noise in the audio?

Wayne Gillispie · #5 10-16-2011, 06:53 PM

None of mine are shielded. I will let you know how it works out soon.

rleffler · #6 10-17-2011, 04:31 AM

Quote:

Originally Posted by rv9aviator

Mine isn't but it is only about 10 inches long. Could that cause any kind of noise in the audio?

Probably not, unless your audio lines are unshielded. RS-232 isn't used for audio. What would have a greater potential to add noise is ground loops. I would refer you to Bob Nuckolls book for more information. He may also have a white paper on his web site.

bob

TX7A · #7 10-17-2011, 08:27 AM

Thanks, Bob & Walt.
I'm seeing three wires that need to be switched (does not include the shield): ARINC A, ARINC B & RS232
Does that sound right?

rleffler · #8 10-17-2011, 08:43 AM

Quote:

Originally Posted by TX7A

Thanks, Bob & Walt.
I'm seeing three wires that need to be switched (does not include the shield): ARINC A, ARINC B & RS232
Does that sound right?

Hard to guess without a schematic, but looks to be correct. Also look at your audio lines.