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Antennas

JDA_BTR

Well Known Member
On the bottom of the plane are two com antenna places near the seats, a place on right side of baggage area, and one aft at the tail. The aft one is rigged for the transponder I think with the coax supplied with the empennage kit. What is commonly done with the one under the baggage area?
 
I'm using it for my mode C transponder, which will work (they claim) with the Echo UAT for 2020 compliance, so no need for the ADS-B antenna in the back
 
Use the one under the baggage compartment for your transponder. With standard rg-400 cable your maximum transponder run typically needs to be under 8 feet in length.

Use the one in the rear for ads-b in if you are doing ads-b in. I'm assuming you will be using a mode s with extended squitter transponder for ads-b out.
 
I'm using it for my mode C transponder, which will work (they claim) with the Echo UAT for 2020 compliance, so no need for the ADS-B antenna in the back

I just helped a friend with an Echo UAT install and you do need a second antenna for ADS-b. Your current antenna will stay connected to your transponder and your Echo UAT will listen for the squawk code and rebroadcast the ADS-b message on it's own antenna.

You can easily install the Echo unit in the tail cone and use that location for your second antenna mount. You just need to run power and some signal wires to the Echo unit to get the rest of the data needed for the ADS-b out signal.
 
Ok I get it use one for transponder and one for Adsb In. Was planning a gtx-45r I?ll look at the book and see what it shows I was thinking one antenna to the unit for both.
 
Was planning a gtx-45r I?ll look at the book and see what it shows I was thinking one antenna to the unit for both.

This is my understanding as well, one antenna for the GTX-45R.
 
Was planning a gtx-45r I?ll look at the book and see what it shows I was thinking one antenna to the unit for both.

Yes, some ADS-b units do both on one antenna. I don't know specifically about the gtx-45r. I use a GDL 39R for ADS-b in, so I need both antennas.
 
Yes, the GTX45R has only one antenna; there is an option for a GPS antenna as well but I won't need that. I read the manual and can't find any limitations about antenna cable length. It does say to keep the antenna away from gear, other antenna's, etc.

So I guess if I wanted I could use the cable run to the tail for the transponder back there; not sure what antenna I would want. I was planning a wingtip Nav antenna; maybe I could just put it under as well rather than just plugging the hole with a plate of some kind.... How well would a cat-whisker antenna work back under the tail?

Wish I'd known this at the beginning!!!!
 
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