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  #11  
Old 03-05-2019, 02:44 PM
Stockmanreef Stockmanreef is offline
 
Join Date: Nov 2012
Location: Midland, mi
Posts: 958
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should I add a doubler plate for the transponder antenna?

did anyone find that the coax cable that Van's supplied with the empennage kit to be too short by a foot or so? It is supposed to run from the back of the tail cone to the panel. It does, but not any extra. Turns out it is not long enough to reach my GTX 45R. If I put it behind the center stack it would have been enough, but I have something else there. So it looks like i will be rerouting to the antenna to the port under the baggage area.

Not a huge deal. Just means that I have to climb into the tail cone and clip all the cable ties and then run the cable where I want it. sort of a PITA, but low on the list of annoying things thus far in the build.
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  #12  
Old 03-05-2019, 02:56 PM
Nova RV Nova RV is offline
 
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Location: Leesburg, VA
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Make sure you want the transponder antenna there for sure before you do that to save a few dollars on coax. The rear mount already has the doubler in place and it's always best to keep the distance between all of your antennas as much as reasonably possible. I also didn't like that there was an antenna pretty much underneath the passenger seat connected to a high output device that is transmitting constantly compared to a regular comm. the nice feature of the GTX 45R is it only needs the one antenna so you don't have to use that hole on the passenger side.
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RV-14A kit # 140243 (flying as of 11/18)

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  #13  
Old 03-05-2019, 03:42 PM
Stockmanreef Stockmanreef is offline
 
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Location: Midland, mi
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just a royal PITA to rerun the cable. It is just the little annoying things that Vans does that irritates me. I would have preferred not having the cable run at all versus it being too short. I would gladly have paid an extra $5 for another ft of coax on that line. Now is is complete useless, unless I put the antenna under the baggage area.

I do see your point and I will probably rerun the cable if I have enough.

If I had figured this out prior to running the comm coax, I could have just cut it in half and used them for the comm antennas. At least then I would have been able to reuse the connectors already in place.

I wonder if the time to build a plane is based on the second build and not the first. I definitely could build the plane in a lot less time the second time around knowing all the BS that I could avoid.
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Ken Stockman
Midland, MI
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FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
N73XP

Plane at hangar and the wings ON.
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  #14  
Old 03-05-2019, 06:07 PM
MED MED is offline
 
Join Date: Jul 2015
Location: Aiken, SC
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Garmin recommends a relatively short distance for the ADSB antenna cable for my 45R. The location under the baggage compartment meets it; the location in the tail does not. It might be ok in the tail, but. I shortened the Van's supplied coax to the baggage compartment antenna location and reused the rest for comm antennas under the seats. I put a dummy transponder twig antenna in the tail to fill the hole.
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Last edited by MED : 03-05-2019 at 06:09 PM.
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  #15  
Old 03-05-2019, 06:07 PM
Nova RV Nova RV is offline
 
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Location: Leesburg, VA
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Quote:
Originally Posted by Stockmanreef View Post
I wonder if the time to build a plane is based on the second build and not the first. I definitely could build the plane in a lot less time the second time around knowing all the BS that I could avoid.
I was just thinking this the other day, I could build another so much better and more quickly too!

Another option is to just put an extra 2 feet in line with an extra male and female BNC connector pair. It will of course add some nominal loss but I would bet for this purpose it would not be of any significance.
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Leesburg, VA

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RV-14A kit # 140243 (flying as of 11/18)

www.mykitlog.com/chrismoon/
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  #16  
Old 03-06-2019, 04:11 PM
Stockmanreef Stockmanreef is offline
 
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there is no recommendation for the length of the coax from the 45R other than is has to be at least 3 ft from the unit to prevent RF interference.

The manual also stated that the transponder antenna be at least 3' from any other com antenna and I don't know what that means--the base of the antennas or the tips.

Garmin indicated that the position in the back of the plane is fine for the transponder antenna.
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Ken Stockman
Midland, MI
EAA Chapter 1093 member

FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
N73XP

Plane at hangar and the wings ON.
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  #17  
Old 03-06-2019, 04:21 PM
Pdtofly Pdtofly is offline
 
Join Date: Jan 2012
Location: Reno, NV
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Default Where to start

When you start running your coax cable. Start with the longest one first, then get smaller. That way, if you cut it to short, you can use it in the next shorter one. You can alway make them shorter, but you can not go back and make it longer.

Good luck, and yes, practice with the connectors. Solder the tip, and don't crimp the tip. Also check them out with an ohm meter before you do the final sleeve crimp, just in case you have a short. You can still fix it then and not waste a connector.

Brian

Last edited by Pdtofly : 03-06-2019 at 11:22 PM.
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  #18  
Old 03-06-2019, 04:52 PM
Stockmanreef Stockmanreef is offline
 
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Location: Midland, mi
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I already crimped several of the tips. What solder? SteinAir video says to crimp. The tip is held in place with the connector and can't slide through (at least with the connectors I used).

I just posted in the "gotchas" thread about the coax provide with the empennage kit. The length of the wire allows the transponder unit to only be placed behind the subpanel in the center stack area, which is very limiting. I put the GTX-45R behind the copilot G3X. Oh, well.

I cut the end off and pulled a longer piece of coax through. Unfortunately, I already ran both comm coax lines as well as the GPS line. Now I have a 15' piece of coax with nothing to do with it--$45 down the drain. I would have gladly paid an extra $3 for a coax cable 1 ft longer with the original kit.
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Ken Stockman
Midland, MI
EAA Chapter 1093 member

FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
N73XP

Plane at hangar and the wings ON.
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  #19  
Old 03-07-2019, 06:45 AM
Stockmanreef Stockmanreef is offline
 
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Location: Midland, mi
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there was a coax cable provided with the empennage kit--unless it comes with one of the other kits. It runs from the transponder hole in the tail cone to the panel (see 10-23--WH-00014). From what I understand, the phone wire runs to the ELT. At least my ELT has no way to connect a coax cable.
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Ken Stockman
Midland, MI
EAA Chapter 1093 member

FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
N73XP

Plane at hangar and the wings ON.
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  #20  
Old 03-07-2019, 03:02 PM
MED MED is offline
 
Join Date: Jul 2015
Location: Aiken, SC
Posts: 571
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There is also (or should be) a coax to connect the tail-mounted ELT with the antenna in the baggage compartment.
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