EEVblog #1352 - Aircraft Transponder TEARDOWN!

[EEVblog]

Teardown of a Made in Australia MicroAir T2000 aircraft transponder.
http://microair.com.au/products/26/T2000SFL-Transponder-Rev8-

[Clear as mud]

At around the 11 minute mark, you hold the board up to the camera and say "this little puppy is not going to reveal what it is."

This is just a guess: power-up sequence timer?  I looked up a couple of those chips.  CD4514B is a programmable counter timer, with clock set by external RC.  And MC14093B is a quad 2-input Schmitt-trigger NAND.

[HyperSpectral]

The FCC website has schematics, BOM, user manual, filter alignment procedures, theory of operation and more. The "Ohm" jumpers are 1 turn inductors for example and the trimmer with the rigid coax tunes the base of the transistor. There is way more insight than just this. The filter tuning procedure includes design approach and specifications. The documents are for a previous revision, but it all seems to be the same basic design.

Just go to the FCC ID search and enter PS3 for the Grantee Code and T2000 for the Product Code.

Enjoy!