encoder delay on startup

[prkaye]

I have an ACK technologies certified encoder going into my GTX327 xpndr. When I fire up my panel, it takes a couple of minues for my xpndr to display the pressure altitude. Is this normal?

[SteinAir]

Yep, the old encoders (that being separate boxes not the internal ones provided in all the new EFISes which are instant) need some time to "warm up"....it's normal!

Cheers,
Stein

[TCONROY]

Yes, this is a correct assesment. Many even have internal heaters to warm them up. In cold temps they can take up to 5 minutes to start outputting data. This is why you want to make sure your transponder is on STBY well before you depart(In STBY mode it outputs the switched power to the encoder).

[Rick6a]

Originally Posted by SteinAir

Yep, the old encoders (that being separate boxes not the internal ones provided in all the new EFISes which are instant) need some time to "warm up"....it's normal!

Cheers,
Stein

As always, Stein's words are golden. A few months ago, I had the local avionics guy certify the biannual transponder check on both my RV's at the same time. The old encoder coupled with the transponder in the -6A took almost 6 minutes to fire up, while the internal encoder in the Dynon fired up instantly. The technician said this is quite normal saying he has seen some older encoders take up to 15 minutes to function properly.