A321 Antenna

[Altcrznav]

Any thoughts as to what this antenna is for? And no, the TCAS one is the circular one to the aft.

[Exrigger]

Possibly a Marker Beacon Antenna:

Marker Beacon Antenna Archives - Sensor Systems Inc., Aircraft Antenna

[tubby linton]

A very reputable source to the A320f says that it is the Tcas.

[Altcrznav]

Originally Posted by tubby linton

A very reputable source to the A320f says that it is the Tcas.

The round antenna is TCAS.

[tubby linton]

I think the round one is the gps and the flat one tcas. There are lots of images here.
TCAS Antenna Archives - Sensor Systems Inc., Aircraft Antenna

[AerocatS2A]

Originally Posted by Altcrznav

The round antenna is TCAS.

Why so certain the round one is TCAS?

[Smithy02]

Our A320 do not have ADFs fitted but that looks like an ADF sense antenna to me.

S02

[Altcrznav]

Originally Posted by Smithy02

Our A320 do not have ADFs fitted but that looks like an ADF sense antenna to me.

S02

ADF antennas are on top.

[Altcrznav]

I’m thinking it is a plug for the old TCAS I antenna. When aircraft was upgraded to TCAS II, the ACSS round antenna was installed.

[LookingForAJob]

A bit of Googling (and only a little bit) 'cos I'm bored suggests it's a MKR.

[pineteam]

How old is this A321? It surely looks like a TCAS antenna.

[sonicbum]

If it's not the TCAS then it must be the Marker. Can't think of anything else with that shape.

[FlightDetent]

The Chemtrails Report Interchange Beam is not displayed for logical reasons, but the location varies for that one anyway.

[Station Zero]

Round one behind is TCAS, not likely to be ATC or DME as they are the small yellow ones.

My guess some kind of air to ground coms, possibly cellular or some kind of gatelink. Not standard as there is a skin doubler externally for it.

[Altcrznav]

Solved

It is not an antenna but a cover plate for the old ATG-4 antenna used for our terrestrial-based internet. We're completely switched over to satellite so, obviously, these antennas were removed.

Gogo ATG-4 - what is it, and how does it work? - Gogo Concourse Blog

[Altcrznav]

Here's a different install of the old antenna.

[Steve Zissou]

Not the GPS aerial ...?

[Wodrick]

GPS = Satellites. Satellites above aircraft. therefore GPS antenna on top, simple.

[Check Airman]

Originally Posted by Wodrick

GPS = Satellites. Satellites above aircraft. therefore GPS antenna on top, simple.

The GPS antenna under the plane is for navigation in the southern hemisphere

[FlightDetent]

Just curious, will GBAS need a separate one?