Had a strange one today..

While squawking IDENT , our "ident" stuck "on"

ATC confirmed we were continuously "identing"

Cycling the transponder to off then on again cleared the
ident fault.

Pressing the button again locks the ident light on again
until the power is cycled..

Any thoughts?

Switch appears mechanically OK, (clicks when pressed, clicks
when released)..

It is a King KT78 "KT76TSO"

Dave

Take it to an avionics shop, it isn't airworthy until you
fix it.




--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm



"Dave" > wrote in message
...
| Had a strange one today..
|
| While squawking IDENT , our "ident" stuck "on"
|
| ATC confirmed we were continuously "identing"
|
| Cycling the transponder to off then on again cleared the
| ident fault.
|
| Pressing the button again locks the ident light on again
| until the power is cycled..
|
| Any thoughts?
|
| Switch appears mechanically OK, (clicks when pressed,
clicks
| when released)..
|
| It is a King KT78 "KT76TSO"
|
| Dave

On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
> wrote in
<4qSdf.1063$QW2.860@dukeread08>::

>James H. Macklin
>ATP,CFI,A&P

Welcome back to rec.aviation.piloting.

Has it been almost five years?

Since 9/11 when I lost the cable Internet. Glad you
remember me. Just renewed my CFI for another cycle, good
until Jan 2008. I plan to win the lottery before Christmas
and buy myself a Legacy Cub. Maybe I'll put half a Garmin
1000 in it ;)



--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm



"Larry Dighera" > wrote in message
...
| On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
| > wrote in
| <4qSdf.1063$QW2.860@dukeread08>::
|
| >James H. Macklin
| >ATP,CFI,A&P
|
| Welcome back to rec.aviation.piloting.
|
| Has it been almost five years?
|

Already gone!

Dave


On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
> wrote:

>Take it to an avionics shop, it isn't airworthy until you
>fix it.
>
>
>
>
>--
>James H. Macklin
>ATP,CFI,A&P

On it's way back, should have it tomorrow....

Including taxes, .219 AMU's.. (CDN $"s)

Suprisingly, they could not reproduce the fault on the bench, so they
replaced the IC, some caps etc, all the parts in the timing circuit,
($35 in parts).. They did a full alignment, centered it to fac specs,
and are sending it home..

I am dissappointed the fault cleared on the bench, that still leaves
some doubt, but they heated it, froze it several times, then did what
they could.

How long should this timer cycle for? (How long should the "ident"
signal tx on one push of the switch?)

Dave



On Mon, 14 Nov 2005 18:21:05 -0400, Dave
> wrote:

>Already gone!
>
>Dave
>
>
>On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
> wrote:
>
>>Take it to an avionics shop, it isn't airworthy until you
>>fix it.
>>
>>
>>
>>
>>--
>>James H. Macklin
>>ATP,CFI,A&P

20-30 seconds

"Dave" > wrote in message
...
> On it's way back, should have it tomorrow....
>
> Including taxes, .219 AMU's.. (CDN $"s)
>
> Suprisingly, they could not reproduce the fault on the bench, so they
> replaced the IC, some caps etc, all the parts in the timing circuit,
> ($35 in parts).. They did a full alignment, centered it to fac specs,
> and are sending it home..
>
> I am dissappointed the fault cleared on the bench, that still leaves
> some doubt, but they heated it, froze it several times, then did what
> they could.
>
> How long should this timer cycle for? (How long should the "ident"
> signal tx on one push of the switch?)
>
> Dave
>
>
>
> On Mon, 14 Nov 2005 18:21:05 -0400, Dave
> > wrote:
>
> >Already gone!
> >
> >Dave
> >
> >
> >On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
> > wrote:
> >
> >>Take it to an avionics shop, it isn't airworthy until you
> >>fix it.
> >>
> >>
> >>
> >>
> >>--
> >>James H. Macklin
> >>ATP,CFI,A&P
>

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..

Thanks !

Dave

On Thu, 17 Nov 2005 01:10:44 GMT, "Michael Ware"
> wrote:

>20-30 seconds
>
>"Dave" > wrote in message
...
>> On it's way back, should have it tomorrow....
>>
>> Including taxes, .219 AMU's.. (CDN $"s)
>>
>> Suprisingly, they could not reproduce the fault on the bench, so they
>> replaced the IC, some caps etc, all the parts in the timing circuit,
>> ($35 in parts).. They did a full alignment, centered it to fac specs,
>> and are sending it home..
>>
>> I am dissappointed the fault cleared on the bench, that still leaves
>> some doubt, but they heated it, froze it several times, then did what
>> they could.
>>
>> How long should this timer cycle for? (How long should the "ident"
>> signal tx on one push of the switch?)
>>
>> Dave
>>
>>
>>
>> On Mon, 14 Nov 2005 18:21:05 -0400, Dave
>> > wrote:
>>
>> >Already gone!
>> >
>> >Dave
>> >
>> >
>> >On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
>> > wrote:
>> >
>> >>Take it to an avionics shop, it isn't airworthy until you
>> >>fix it.
>> >>
>> >>
>> >>
>> >>
>> >>--
>> >>James H. Macklin
>> >>ATP,CFI,A&P
>>
>

"Ident" times...

Garmin GTX 330 = 18 seconds

Microair T2000 = 20 seconds

As per their manuals...


"Dave" > wrote in message
...
> 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..
>
> Thanks !
>
> Dave
>
> On Thu, 17 Nov 2005 01:10:44 GMT, "Michael Ware"
> > wrote:
>
> >20-30 seconds
> >
> >"Dave" > wrote in message
> ...
> >> On it's way back, should have it tomorrow....
> >>
> >> Including taxes, .219 AMU's.. (CDN $"s)
> >>
> >> Suprisingly, they could not reproduce the fault on the bench, so they
> >> replaced the IC, some caps etc, all the parts in the timing circuit,
> >> ($35 in parts).. They did a full alignment, centered it to fac specs,
> >> and are sending it home..
> >>
> >> I am dissappointed the fault cleared on the bench, that still leaves
> >> some doubt, but they heated it, froze it several times, then did what
> >> they could.
> >>
> >> How long should this timer cycle for? (How long should the "ident"
> >> signal tx on one push of the switch?)
> >>
> >> Dave
> >>
> >>
> >>
> >> On Mon, 14 Nov 2005 18:21:05 -0400, Dave
> >> > wrote:
> >>
> >> >Already gone!
> >> >
> >> >Dave
> >> >
> >> >
> >> >On Sun, 13 Nov 2005 20:12:43 -0600, "Jim Macklin"
> >> > wrote:
> >> >
> >> >>Take it to an avionics shop, it isn't airworthy until you
> >> >>fix it.
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>--
> >> >>James H. Macklin
> >> >>ATP,CFI,A&P
> >>
> >
>

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).

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.