Squawk code

[Steevo25]

Hi All,

I currently have a Trig TT22 transponder that is couled to a Garmin GPS-18X. I purchased the PilotAware system to really just view what was in my area and test my own ADS-B install. When I have my transponder on and run up the PilotAware Traffic screen, I can see my aircraft there with all the details I would expect to see but it does not display a squawk code. No matter what I change the squawk to on my transponder, the squawk code is always blank.

I also have a transponder ramp tester which shows the squawk from my transponder and ATC have no problem seeing my squawk. Why does this not display in PilotAware? I see other aircraft (mainly commercial jets) and these are shown with the squawk code.

[Admin]

Hi Steevo,

Hmm, I cannot recall if the squawk is sent as part of the Extended Squitter or the Mode S interrogation.
If it is the Mode S interrogation, then of course - your transponder needs to be interrogated

Where is the measurement conducted, I am presuming on the ground / hangar maybe ?

In which case this would explain why you do not see a squawk code.

Thx
Lee

[Steevo25]

Many thanks for your reply Lee.

At the moment, I have only used it on the ground with it connected to my laptop. This is outside on the airfield. Usually I pick up around 15 aircrafts with nearly all being commercial jets at 20000ft plus. I often see a couple of others. Mine is always listed first and is shown in red as its 0km away. It shows my aircraft registration, altitude and all the other parameters but the squawk code is always shown as blank even though I select a random 4 digit squawk and have the Trig set to Alt.

Would it make a difference if I was in the air, how would it know? I am around 300ft AMSL at the airfield.

I can always tell the commercial aircraft against private because my Trig won't let me enter a dash in the reg name whereas commercial aircraft seem to allow it.

[grahambaker]

What Lee means by 'being in the air' is that if you were actually airborne, you'd probably be high enough to be hit by a Secondary Radar pulse, which would trigger your transponder to reply with your squawk. On the ground you are almost certain to be invisible to any radar head, so your transponder sits there doing nothing.

[JCurtis]

A transponder ramp tester can generate a interrogation pulse to trigger a transponder, its just at a very low power transmitter.  So I'd expect the transponder to reply with its squalk.

It might be the transponder is swamping the receiver, so either try moving further away or if a metal skinned aircraft put the PAW inside. If you're really close just unplugging the aerial might do the trick.

[grahambaker]

Steevo,

Just to be sure, have you tried your Pilot Aware at the same time as using your transponder test kit?

[Steevo25]

Thanks for all you replies, that makes sense. I have not tried my ramp tester at the same time as running pilotaware.

I am at the airfield today so will give that a try.