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Advanced Aircraft Electronics High Gain Transponder Antenna (L2)

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Part# 11-04212


These aircraft antennas specifically designed to be used without a ground plane. Composite aircraft and fabric covered aircraft can have their antennas mounted totally within the structure. These antennas are designed using the latest engineering technology. They will work in metal airframes when a plastic or fiberglass wing tip or similar plastic component is available to provide the mounting structure.
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  • Inside mounting.
  • Use w/ composite skins.
  • Use with fabric covered airframes.
  • Glue or bond to the airframe. Light weight.
  • Wide service temperature,
  • No ground plane corrosion, Mount anywhere inside, Maximum range with low VSWR.
  • Model L2 series designed for transponder.
  • Guaranteed against failure for the life of the airframe.
  • Adapts to existing airframes or to in process construction.
  • Glue or bond to the airframe. Light weight. Wide service temperature, No ground plane corrosion, Mount anywhere inside, Maximum range with low VSWR. Model VHF series designed for comm or nav or ELT. Guaranteed against failure for the life of the airframe. Adapts to existing airframes or to in process construction.


Q. What cable length is recommended for the antenna ?
A. Any length can be used. This antenna is impedance matched to 50 ohms to allow you to use any length required.

Q. Can I use it in the plastic or fiberglass wingtip of a metal airplane ?
A. Yes, but the antenna must be as far from the metal wing as possible. We have had limited success with this. Not recommended for the RV series aircraft.

Q. Will the strobes cause interference ?
A. It is possible to couple the strobe audio squeal into the VHF radio. Thishappens when the antenna is close (about a foot) to the strobe.

Q. I thought the com antenna has to be vertical to work.
A. For maximum sensitivity, this is best. The VHF-5 antenna has a higher gainthan others but still when mounted in the horizontal plane the resultantsensitivity is reduced but useable.

Q. Can I mount the antenna on a metal part of my airframe?
A. No ! This antenna works best when separated from all large metal objects.Mounting it on any metal destroys its antenna properties.

Q. Some people have good operation with a ground plane working with their antenna, does this one do the same?
A. No, any ground plane will destroy the effectiveness of this antenna.

Q. My fabric airframe is completed, where is the best location for the antenna?
A. Mount it on a wood brace in the fuselage behind the cockpit. Fasten one end to a location on the lower part of the fuselage frame corner. Then fasten the other end to the opposite or diagonal part of the inside of the upper framecorner. Fasten the antenna to this installed piece of wood.

Q. Should I be careful of the angles at which I mount this wood?
A. No. As long as the antenna is in the same plane as the plane of rotation ofyour propeller, it'll work.

Q. What happens if I mount the antenna on one of my wood stringers on the fuselage?
A. The maximum range will always be off to the sides and the minimum range will be ahead and behind you.

Q. What happens if I mount the antenna on my wood spar in the wing?
A. The maximum range will always be ahead and behind you and the minimum range will off to the sides.

Q. What if the antenna has to be mounted with a bend to fit in the space I want to use?
A. Curving the antenna will fill in those minimum range areas mentioned above at the slight expense of the maximum range.

Q. Can't I have both?
A. No, only a fixed amount of energy can be radiated. If you redirect energy tofill in holes in the pattern you must remove some from one part of theradiation pattern to fill in the other.

Q. Why is it so long compared to others?
A. This is a dipole which is half wave length long and makes it about twice aslong as quarter wave antennas.

Q. Can this be made shorter ?
A. No, it must be used as manufactured. If it is cut to fit, it will be destroyed.

Q. Do I need a 337 ?
A. Perhaps. This is between you, your IA, and the local FAA. It mounts insideand so does not alter the airflow, it attaches with adhesive so no holes oralterations are required for the airframe mount, and it is too light weight toaffect weight and balance.

Q. Will this work on my canopy?
A. Yes, but keep it as far from the metal frame as practical.

Q. Why do I have to keep it away from metal things?
A. Any metal alters the characteristics of the tuning and pattern in unpredictable ways. Each airframe installation is different, so we recommend that you use tape and experiment with locations until you are satisfied with the operation.

Q. Where is a good location in my fiberglass fuselage?
A. Put the com antennas on either side in the tail cone, & if the fuselage isn'ttall enough bend the antennas to resemble the letter"C". If you are using two,stagger them on opposite sides and try to have about 24 inches or more in thestagger.

Q. Why haven't I seen this type of antenna previously?
A. This design has been in operation since 1981 but in response to consumer demand they are now being produced for the non-metal airframe market.

Model Differences

  • The L2 transponder antenna has the BNC connection positioned so that the coax cable would route out and away from the antenna mounting surface. This configuration is offered for antenna installations such as wing tips of fabric aircraft. If the antenna is mounted on the inside of the tip, the coax route is directly inward toward the wing root and the BNC connection is located near the spar to provide support for the cable.


In the Box

  • 1 - Antenna
  • 1 - 3/8" strip of balsa which should be sandwiched between the antenna and the airframe structure.


Product is really good, easy to install. Only availability is limited.

(v) V Verified Purchase


March 7, 2024

Magaero L Verified Purchase


September 17, 2022

I installed this antenna in my composite fuselage, experimental aircraft, back in 2006. It has worked just perfectly since then and more than 1,200 hours flying. Excellent product.

Alejandro R
December 21, 2019

Installed in the nose of a long EZ (in front of feet) - works great, confirmed working with ATC

April 8, 2018

Installed in the bottom of the aft fuselage on a Glasair 1TD. Prior antenna was a standard Transpoder unit drilled through the bottom. Performance was challenged based on the lack of adequate ground plane. This L2 Antenna solved it - performance was more than passable by my local avionics shop.

Aaron M
April 24, 2017


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Is BNC connector perpendicular to mounting surface, or parallel to mounting surface?

The BNC connector is parallel to the mounting surface.

Q: Can this Advanced Aircraft Electronics L2 antenna be mounted in a carbon fiber aircraft, or with some metal in the vicinity but not within six inches of the metal?

No, the carbon fiber will act as a conductor and prevent this antenna from working.

Q: Will this Advanced L2 Transponder antenna work with ADS-B transponders?

Yes, mode S transponders are compatible.

Q: Can this be mounted on any angle or is the orientation critical?

Per the manufacturer, we can only recommend vertical mounting orientation.

Q: Is this antenna suitable for use with an ELT?

No, the L2 antenna is not rated for ELT use.

Q: Will this Antenna work with the new ADS-B transponders?

Yes, it will.

Q: Can this Antennae be used for anything else? COM/NAV etc?

This is an experimental antenna meant for transponders. You will not be able to use it for COM or NAV.

Q: Is this antenna compatible with Trig TT22 mode S transponder?

This antenna is for experimental aircraft only. Per the manufacturer it will work.

Q: What are the dimensions of the L2 antenna?

It is 5.5 inches long x 1 inch wide.

Q: Is this antenna compatible with a Garmin GTX335 transponder for an experimental aircraft?

The installation manual does not list this antenna as a compatible antenna.

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