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Where to Mount ADS-B GPS Antenna

Allen Rice

Member
I'm installing the Stratus ESG transponder/ADS-B out unit and was told by the Appareo rep at Sun N Fun that many RV'ers had successfully mounted the GPS antenna on the firewall. Well, I tried it and while I do receive a good GPS signal on the ground with the engine off, there is no joy in the air! I hate to put the big ugly hockey puck on the turtle deck of my 9A, so does anyone have an alternate suggestion?
 
I'm one of the RVers that successfully runs the ESG antenna under the cowl (as high up on the firewall as possible). I'm puzzled why your installation isn't working. Since it works with the engine off but goes offline with it running, I wonder if you relocated it under the cowl it might work properly. It may be getting hit with RMI...do you have an electronic ignition?

There just ain't a good place to mount that ugly antenna on the exterior of our little planes. My second choice was going to be in the baggage compartment.

Once you get it running you will find the ESG is an excellent ADS-B out solution at a very attractive price.
 
One more thought....did you follow the directions for minimum coax length? Too short and the receiver might be getting overloaded in the air.
 
Thanks for the tips Sam. The problem might be a too short RG 400 cable. Mine is only 40" and on your advice I re-checked the install instructions and they say minimum 10'! Did you just coil up all the excess under your panel? Boy I hate wasting those expensive TNC connectors to make a new antenna cable.
 
Thanks for the tips Sam. The problem might be a too short RG 400 cable. Mine is only 40" and on your advice I re-checked the install instructions and they say minimum 10'! Did you just coil up all the excess under your panel? Boy I hate wasting those expensive TNC connectors to make a new antenna cable.

I used RG-58 which has a seven foot minimum and is MUCH lighter (and less expensive) than RG-400. Yes, the excess is coiled up behind the panel. Look at the last page of the following doc for more info about coax lengths:

http://www.rst-engr.com/rst/products/adsb/Images/rst-appareo.pdf
 
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GPS Antenna Location

I have one installed on a self bent bracket riveted to my wingtip rib for a Garmin GNC300XL. Works great under the fiberglass wingtip for 500 hours & 13 years of flying and has been trouble free and it is not in the way when doing engine work.

Dick DeCramer
Las Cruces, NM
N500DD RV6
 
I have one installed on a self bent bracket riveted to my wingtip rib for a Garmin GNC300XL. Works great under the fiberglass wingtip for 500 hours & 13 years of flying and has been trouble free and it is not in the way when doing engine work.

Dick DeCramer
Las Cruces, NM
N500DD RV6

That sounds like an excellent solution and is a good way to use up the excess coax length. :)
 
I arrayed five satellite antennas across the top of the glare shield. Ugly as sin, but not in my line of sight. Besides the 10' requirement, each of the little Garmin and Sirius antennas has a 10' pigtail. Lots of coiled up wire behind the panel.

To get around weight and expense of RG400, I installed an appropriate load from the local electronics store. Sort of surprises me that some enterprising RVer hasn't developed one for our short-reach applications. The 650 seems to function properly, but that's only my observation, no instrumentalities were involved to measure electrical characteristics.

John Siebold
 
Sam, thanks for the coax tech info. I'll be installing the longer cable today. BTW, flew to 24J for pancake breakfast this morning and the ESG worked perfectly. Go figure.
 
I bought a factory made 10' RG400 cable on eBay for $12. Installed the GPS antenna under the RV-12 engine cowl and coiled up the excess cable. My Appareo Stratus ESG passed the government test to qualify for the $500 rebate. Received an email saying that the check is in the mail.
Read what Stein posted about short GPS cables HERE.
 
Just a comment on this ADS-B transponder.
We installed this in our RV6 tip up & it has worked perfectly on numerous cross country flights.
Using Foreflight into iPad mini for ADS-B In. Which is awesome..!!
We used 4' of RG400 coax from the glare shield mounted antenna to the transponder. Didn't notice the 10' coax requirement during the installation process!!
100% compliance report & received the $500 rebate.

On some installations, the minimum specified coax length is not because the gps signal is too strong. Rather, some unwanted signal may be too strong and overload the receiver (maybe an FM station? Who knows?). Point is, just because you passed the test during a one hour flight is no guarantee that some day you won't find your gps receiver not working. The manufacturers don't put out these minimum coax requirements for no good reason. Ignore them at your risk.
Edit: In the case of a TSO device you may not legally ignore the installation instructions (if you want the TSO to be valid).
 
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Progress Report

Since first installing the Stratus ESG last month and switching to a 10' antenna cable installed through the firewall from the GPS, I passed the test and got my $500 rebate in just 4 days from the FAA. Thanks for your help.
 
Great to know about cable length, thanks for the update.

I'm planning on installing the Garmin GDL-82 when it comes available.

Does anyone know if mounting the WAAS GA 35 GPS antenna that comes with the GDL-82 next to my GA 25MCX antenna for my Aera 660 will cause any issues?

Maybe Garmin or Stein will know?

Thanks,
Shawn
 
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