bobmarkert

bobmarkert

Well Known Member


I soldered the connectors for my GTN650 comm antenna. After soldering the ends I did a continuity test between both ends (pin and case) and insured there was no short between the case and the pin. All was well until.... I attached the antenna cable to the GTN. For grins I retested the antenna end and I now have continuity between the pin and the case at the antenna end. Unplug it and no continuity. Does the GTN 650 radio create a bridge between the center pin and the case? Normal or not? Thank you.
Bob
 
Good morning Bob,

A continuity tester will usually be fooled if you connect it to something that contains any kind of circuitry beyond a simple "open or closed" switch. A continuity test is, after all, just a resistance test. If you've verified - with both the antenna and the radio removed - that the cable has proper continuity from end to end and no short circuits, I wouldn't worry about it. Build on, as they say!

- Matt
 
I've done the tests and they were fine, back to building the next part.
Thank You
 
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As others have said, build on. If you are concerned, you can borrow or buy a SWR meter to test the cable and antenna.

I used one of these:

4828.jpg


A local HAM Radio operator may be willing to give you a hand with this.

bob
 
lacing cord FWF

Next up.... Is it accepted practice to use lacing cord to "neaten up" wiring bundles FWF?
humbly
Bob
 
bobmarkert said:
Next up.... Is it accepted practice to use lacing cord to "neaten up" wiring bundles FWF?
humbly
Bob
Click to expand...

Not only is it acceptable, it's preferred. There is a FAA publication (and the name escapes me at the moment) that documents the acceptable practices for construction of your aircraft. It's the bible that inspectors will use when you get your airworthiness certificate. I would download the PDF or purchase a copy. I'll post the name as soon I can remember it or somebody else beats me to to it.
 
The standard nylon lacing cord is good to 250 F so just keep it away from the cylinder heads and exhaust...:)

Higher temperature versions are available but should not really be needed.
 
I'm going from memory and will have to check and confirm. I seem to remember ac 43.13 stating that waxed lacing should not be used fwf. That makes sense, the wax would melt and the knot could become loose.
 
WingsOnWheels said:
I'm going from memory and will have to check and confirm. I seem to remember ac 43.13 stating that waxed lacing should not be used fwf. That makes sense, the wax would melt and the knot could become loose.
Click to expand...

True, but I'm not aware of anyone mounting their gtn650 fwf. :D
 
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