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Antenna for transponder, ADS-B

bob888

Well Known Member
Garmin seems to specify blade type antennas for both the transponder and ADS-B (GDL39R) unit. Has anyone used the much less expensive monopole type antenna for either or both of these units?
 
Just an observation... A quarter wave antenna is not sophisticated. The monopole has been in use for decades on every type of transmitter and receiver you can imagine. Housing a short piece of conductor in a fancy blade, stick, etc. is great for being aerodynamic on really high speed aircraft. I met the guy who came up with the TCAS antenna for the French Concorde. In those cases, it actually matters... due to the high speeds and heat etc.
My Garmin picks up more stations on ADS-B than it needs on all my flights to bring me weather and traffic. It is attached to a thirteen dollar stub on the belly. Don't get me wrong. I often spend more than I should on a piece of gear that just looks cool or has a feature that is seductive. But, speaking as one who works closely in avionics.... a simple antenna is all that is needed on the bottom of most RV's.
 
Garmin seems to specify blade type antennas for both the transponder and ADS-B (GDL39R) unit. Has anyone used the much less expensive monopole type antenna for either or both of these units?

You may want to take a look at deltapopaviation.com. Don makes great antennas for the experimental market and sells them at a price much less than the certified competition.
 
The rod and ball antenna works just fine for both. Not nearly as strong (easily broken), but just as functional.
 
I just ordered a dipole ADS-B antenna from aircraft & spruce $17.00 designed for 978 my. Slightly longer than a transponder antenna. Haven't tested but expect a better signal
 
There is nothing magical about a blade or rod antenna. Electrically they are exactly the same.

Base your selection on:
- Value
- Durability
- Drag

I have the DeltaPop ADS-B antenna and a on my RV-10 and it works as advertised. If I had to buy a transponder antenna today I'd get the DeltaPop as well as it best meets the above criteria.

Carl
 
I noticed a grasshopper had hit the front of my RV on approach to Tucson yesterday. So, I did some calculations. The drag factor on the guts is 11.778 times that of bird poop. I will be spending the morning cleaning and getting my airspeed back. Y'all have a good Friday.
 
DP antennas

+1 for Delta Pop Antenna, Mr Don is a very kind guy ; I have five delta pop antennas on my -7 (in short final of build) 2 bent comm for belly, 1 ultra low drag for Dynon txp and 2 other for Power Flarm anti collision system, one of those is built for specific 868 MHz request for that device.
All antennas works great already from the shop

ciao
 
Since we're on antenna locations...

I noticed Jesse Saint recommended putting the transponder in the tunnel just aft of the firewall (on another recent post). Based on other's reports, I'm thinking it may get a bit too warm there for the electronics to be happy. Does anyone else have experience with this location (which would certainly be convenient in my case)?
 
I just mounted my transponder, ADSB receiver and ELT behind the baggage bulkhead. I have seen other websites with these mounted in this location. I have not heard of any issues with heat buildup. These unit pull .6 amps total. With this large area I cannot see heat being an issue.

Anyone with real world experience either way?
 
Hmmm.... I have a 3d printer and a Solidworks license. Anyone have a suggestion on what airfoil to try? Would be simple to house the ball on a stick inside.

I can print in ABS, PLA, polycarbonate.... Others too
 
I'm a little confused on something that I know you guys will know the answer to. If I go with the garmin GTX 23 ES, I only will need one antenna to satisfy XPNDR/ADSB in/out requirements, correct? It seems like many people are planning on two antennas. Am I missing something?
 
Hey Andrew, I just went through this same question process myself, so I'll try and answer here. Basically, the GTX23ES is an "ADSB Out" transponder (no "in"), and connects to its own transponder antenna. Unfortunately, it doesn't do "ADSB In" to get things like traffic and weather information though. In order to get that capability, you need ANOTHER box, the GDL39R, which connects to a separate transponder antenna. Hence a lot of folks these days, including probably me, need two transponder antennas.

Garmin does make an all-in-one box called the GDL88, but it's a lot more expensive (about $1000 more than the other two boxes combined, if I remember).
 
Garmin seems to specify blade type antennas for both the transponder and ADS-B (GDL39R) unit. Has anyone used the much less expensive monopole type antenna for either or both of these units?

Not Garmin, but Skyview here...using the simple TED XPDR antenna for both, works great.

Although I have to admit...I'll pay $ to gain speed, so does anybody have any data on the actual drag from both the rod-and-ball vs. Comant-style faired antennae?
 
Are you using a single monopole antenna for both the transponder and ADS-B out box via an antenna splitter?

George
 
I believe poster was saying , a TED type transponder antenna x2. They are practically the same wavelength, and per Galin H. radio guy/ poster here, the difference is next to nothing.
 
I believe poster was saying , a TED type transponder antenna x2. They are practically the same wavelength, and per Galin H. radio guy/ poster here, the difference is next to nothing.

And Galin knows his stuff (not saying it just because he was my boss decades ago in the Air Force :D)
 
I believe poster was saying , a TED type transponder antenna x2. They are practically the same wavelength, and per Galin H. radio guy/ poster here, the difference is next to nothing.
You must have two separate antennas if you have two separate pieces of equipment, ie a transponder and a separate ADS-B receiver. Do not use one antenna for a transponder and Separate ADS-B receiver, even with a "splitter".

And Galin knows his stuff (not saying it just because he was my boss decades ago in the Air Force :D)

I remember those great days and those HUGE transmitters.

:cool:
 
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