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Show Me Your GPS Antenna Wiring

iamtheari

Well Known Member
I am measuring my RV-14 for antenna cables so I can hire a professional (Stein Air) to assemble them for me. Some things are just easier that way instead of buying all the right tools.

I am installing a GTN 650. I am planning to mount the GPS/WAAS antenna for it on top of the tailcone, just behind the 1406 aft baggage bulkhead. But I am debating whether to run the cable for it down at that point or first aft to the 1407 bulkhead where I can run it with the static line, using the pre-punched holes for zip ties.

I'm curious how others have solved this small thing. Thanks in advance for any tips or pictures. Or the exact length of antenna cable that worked perfectly to get from the antenna to the back of the GTN in your panel. :)
 
I ran mine along the central belly longeron, then around the bulkhead with the static line, and finally forward to the antenna position. BTW, I mounted 2 antennas on the turtle deck behind the rear window: one for the 650, and a second one that provides gps to the G3Xs and is also the XM radio antenna. There is a spec for how far apart to keep them.
 
I ran mine along the central belly longeron, then around the bulkhead with the static line, and finally forward to the antenna position. BTW, I mounted 2 antennas on the turtle deck behind the rear window: one for the 650, and a second one that provides gps to the G3Xs and is also the XM radio antenna. There is a spec for how far apart to keep them.

Would you happen to have any pictures of your cable run and location of antennas that you could post?
 
Would you happen to have any pictures of your cable run and location of antennas that you could post?
I don’t seem to have any pictures of the cable runs, and the only shot I can find that shows the antenna locations was taken in the paint shop. The Garmin installation manual gives the specifics for the doubler plates you rivet to the skin.
 

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Does Garmin still spec a minimum coax length? That may determine the length you order.

The GTX 45R manual (revision 1 page 3-7) says a minimum of 3 feet. I measured 100 inches from where I mounted the tray (between the copilot panel and sub panel) to the fuselage belly transponder antenna mounting location. I know that some people mount the remote transponder in front of the elevator bellcrank, which could allow for a cable that violates the 3-foot minimum, but I don't have that problem.

I don't see anything in the GTN 650 manual about minimum cable length. I measured 54 inches from the comm antenna locations to the back of the GTN tray mounted high in the center of my panel and a few inches more to where I mounted the GTR 20 (between the pilot panel and sub panel).

I measured about 160 inches from the back of the GTN 650 tray to the top of the turtle deck just behind the baggage bulkhead, following the baggage bulkhead. It is about 24 inches from the baggage bulkhead to the next one aft.

I measured 200 inches from the back of the GTN tray out to the right wingtip.

I am putting in an order now. I gave myself 24 inches of bonus cable on each of these. So my lengths are:
COM1: 80"
COM2: 80"
NAV1: 224"
GPS: 236"
XPDR: 124"

I'm hoping these all work out acceptably but I'll report back here if not.
 
I have an older gtn installation manual (that’s what you really should have) and it says coax run should be a minimum 6.5’, max 35’, for RG-400, so you’re well within those numbers.
 
The GTX 45R manual (revision 1 page 3-7) says a minimum of 3 feet. I measured 100 inches from where I mounted the tray (between the copilot panel and sub panel) to the fuselage belly transponder antenna mounting location. I know that some people mount the remote transponder in front of the elevator bellcrank, which could allow for a cable that violates the 3-foot minimum, but I don't have that problem.

I don't see anything in the GTN 650 manual about minimum cable length. I measured 54 inches from the comm antenna locations to the back of the GTN tray mounted high in the center of my panel and a few inches more to where I mounted the GTR 20 (between the pilot panel and sub panel).

I measured about 160 inches from the back of the GTN 650 tray to the top of the turtle deck just behind the baggage bulkhead, following the baggage bulkhead. It is about 24 inches from the baggage bulkhead to the next one aft.

I measured 200 inches from the back of the GTN tray out to the right wingtip.

I am putting in an order now. I gave myself 24 inches of bonus cable on each of these. So my lengths are:
COM1: 80"
COM2: 80"
NAV1: 224"
GPS: 236"
XPDR: 124"

I'm hoping these all work out acceptably but I'll report back here if not.

I came up with similar measurents today (all measurements to the center of the radio stack):

213" to wing tip
53" to the doubler under the seats
170" to the turtle deck

These do not have a fudge factor built in.

Are you not using the cable that came with the tail kit for the transponder?
 
I came up with similar measurents today (all measurements to the center of the radio stack):

213" to wing tip
53" to the doubler under the seats
170" to the turtle deck

These do not have a fudge factor built in.

Are you not using the cable that came with the tail kit for the transponder?
I deleted the kit's transponder cable because I am not using the aftmost hole and I think it's set up to get back to that one.
 
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