Transponder problem...

Ron Natalie wrote:
Dave wrote:

Hmmm... that seems like a long time... tech said mine is suposed to
be set for 15 secs, and I thought that was very long time.

Can anyone direct me to a resource that explains how the "ident" sys
works? - what happens when the button is pushed, to how it appears
on the controllers radar..
I understant WHAT happens in basic fashon, I need some more details.
I have a background in electronics, so I understand the technology,
but never any training on avionics..


When you push the transponder ident button, for the next 15-20 seconds
any reply the transponder receives has an additional pulse (called in
transponder terms the "Special Position Identification Pulse") added
to the end of the reply. Pressing the IDENT button does nothing if
you aren't being radar interrogated.

How this is displayed to the controller depends on what radar they
are using. Either the little splat on the screen that corresponds
to your aircraft changes appearance (the slash doubles) or the word
IDENT appears in your data block (knowing the hacked nature of
ATC radars there are probably more options).

The explanation I received years ago was your transponder replies with
12 bits of switch settings (4 switches with 3 bits each) and one more
that reflects the IDENT button.

Stubby wrote:

The explanation I received years ago was your transponder replies with
12 bits of switch settings (4 switches with 3 bits each) and one more
that reflects the IDENT button.

The twelve data bits (which are either the transponder code or the
encoded altittude) are always sent along with a beginning and
ending framing pulse. The SPIP is sent 4.35 microseconds
after the last framing pulse only when identing.

Well....

Operational check today.. xponder working fine, Ident working
properly

Hopefully the whole thing certed next week

Ah.. joys of aircraft ownership...

Flew 3 hrs today...smooth air, working trip, 2 hrs flying instead of 5
hrs driving...Cher on the CD player....

Makes working on the weekend almost fun!

Dave


On Thu, 17 Nov 2005 13:56:49 -0500, Ron Natalie
wrote:

Stubby wrote:

The explanation I received years ago was your transponder replies with
12 bits of switch settings (4 switches with 3 bits each) and one more
that reflects the IDENT button.

The twelve data bits (which are either the transponder code or the
encoded altittude) are always sent along with a beginning and
ending framing pulse. The SPIP is sent 4.35 microseconds
after the last framing pulse only when identing.