Iweisenthal
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There have been a few posts about not running transponder coax and power wires together. I’m wondering if there is a general guide as to what I can and can’t route together when wiring my AFP.
Wire/coax incompatibility
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Rhino
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Generally speaking, it's best to run audio, power and RF wiring separately, but we all know that isn't always possible. The intent is to avoid induced coupling. That's most often a problem with audio wiring, but power wiring can carry noise to other places too. Strobe power wiring is notorious for introducing noise elsewhere. When different wiring must cross paths, try to do it at a right angle (perpendicular) rather than running parallel together. When they must be run in the same direction, try to keep as much separation as possible. You can also use shielded cabling for your power wiring as an extra precaution. I recommend you always use shielded wiring for audio.
Standard wiring practices (not necessarily requirements for experimentals) are covered in FAA Advisory Circulars AC 25-26, AC 43.13, Chapter 11, AC 43.13-1b, AC 25.1353, and AC 20-168. Someone else may know of more.
These also appear to be handy references:
This thread briefly discusses induced coupling, but more in the context of audio rather than power and RF.
forum.flydynon.com
Standard wiring practices (not necessarily requirements for experimentals) are covered in FAA Advisory Circulars AC 25-26, AC 43.13, Chapter 11, AC 43.13-1b, AC 25.1353, and AC 20-168. Someone else may know of more.
These also appear to be handy references:
This thread briefly discusses induced coupling, but more in the context of audio rather than power and RF.
Ground Loops and Noise in Aircraft Systems
Quite a few forum threads and articles have at various times addressed ground loops, and their potential to cause noise or other interference in your avionics system. Simply put, a ground loop occurs when different paths to ground are used. The difference in resistance, or impedance, on those...
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Iweisenthal
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That AC 20-168 sure was vague.
Rhino
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I didn't read it. I just saw it had replaced 25-10. You can still get 25-10. Those all came from an old list of recommendations from the FAA. As I said, they may not apply, and none are mandatory.
I should also note you should always use RG-400 or better for antenna cabling. RG-58 and RG-6 cables are just problems waiting to happen.
I should also note you should always use RG-400 or better for antenna cabling. RG-58 and RG-6 cables are just problems waiting to happen.
jnmeade
Active Member
RG142 is solid core so isn't as good for flexibility and has a bigger turn radius, but it has better attenuation and for runs over 15' may be better than RG400. I used both in my homebuilt, depending on the application.