Ttransponder question #3

Ross,

What do you do when requested to "recycle" your transponder?


I take the hint and switch it on after previously forgetting to ;-)

Or, if it is on, I switch to off and back on.

--
Thomas Borchert (EDDH)

On 16 Sep 2005 01:08:10 GMT, (Jay Masino)
wrote in ::

I don't think the transponders actually check for warmth.

A transponder contains what is termed a Crystal Oven. This is a small
chamber in which there is a heating element and a quartz crystal used
to determine the transponder's transmission frequency. It takes time
for the oven to bring the crystal up to the specific temperature to
which it is set. If the oven were not thermostatically controlled, it
would not be able to provide a stable reference frequency at all
ambient temperatures in which the transponder operates.

"Larry Dighera" wrote:

I don't think the transponders actually check for warmth.

A transponder contains what is termed a Crystal Oven. This is a
small
chamber in which there is a heating element and a quartz crystal
used
to determine the transponder's transmission frequency.

Which brands/models have that feature?? The frequency accuracy
required by the TSO can be and is achieved without a crystal oven.

The built-in turn-on delay is merely to allow the high-voltage
supply to come up to full volts, and the cavity tube filament to
heat up.

Fred F.

TaxSrv wrote:
A transponder contains what is termed a Crystal Oven. This is a small
chamber in which there is a heating element and a quartz crystal used
to determine the transponder's transmission frequency.

Which brands/models have that feature?? The frequency accuracy
required by the TSO can be and is achieved without a crystal oven.

The built-in turn-on delay is merely to allow the high-voltage
supply to come up to full volts, and the cavity tube filament to
heat up.

Be that as it may, I believe most transponders just wait a static timeout
amount (30-45 sec), whenever transitioned from OFF to ON, even if you've
already had it on.

--- Jay


--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.OceanCityAirport.com
http://www.oc-Adolfos.com

Oh, thanks!!!

What is interesting is that I get an occasional reported loss of Mode C
in one area that I fly when under IFR or FF. Departure questions me. No
problems other places. Like there is a hole there. I also was
embarrassed once when taking off and told to contact departure which I
did and they asked me to turn on my transponder. Yep, I forgot to do it.


-------------
Regards, Ross
C-172F 180HP
KSWI


Newps wrote:


Ross Richardson wrote:

What do you do when requested to "recycle" your transponder?


Immediately buy a new one. You need to spend at least $1500 to make
this work.

Interesting. I always left mine in standby to allow for warm up before
going to ALT and transmitting. You mean I can just leave the sucker on
all the time? Mine is an old King KT-78.


-------------
Regards, Ross
C-172F 180HP
KSWI


Jay Masino wrote:
Ross Richardson wrote:

What do you do when requested to "recycle" your transponder?


I check to see if something isn't set correctly, but othewise I don't do
anything. Turning the transponder off and on again practically guarantees
that it won't transmit for 30 to 45 seconds, because all modern
transponders are build to wait that long, before starting to transmit, to
allow for warm-up.

--- Jay

So it is OFF and not just STANDBY?


-------------
Regards, Ross
C-172F 180HP
KSWI


Newps wrote:


unicate wrote:

Ross Richardson wrote:

What do you do when requested to "recycle" your transponder?



I was told that was the ATC's way of saying, "Hey...you forgot to
switch your transponder to ALT before you took off!" without
embarrassing you.


Wow, lots of misunderstanding out there. Recycle transponder means to
turn it off and then back on again. "Check your transponder on" means
you have taken off and we are not receiving it when we expect to. "Check
mode C on" means we are getting the transponder but no altitude
information. If we are getting the transponder return and an altitude
but you didn't tag up properly it is because the code is wrong. 75% of
the time it is because you entered it wrong, the other 25% of the time
is because you are hangaing on to that piece of **** and even though you
entered the code right it decided to transmit a different code. Banging
on it usually clears it up.

I'm not real sure on this, perhaps one of the electro-geeks will correct
whatever I get wrong.

My understanding is that older transponders used something called a "cavity
tube" that had a relatively short life and was expensive to replace.

Supposedly, when the transponder was on "Standby" the cavity did not age as
much as it did when "On".

Which meant that you were using up the "expensive" hours flying, when the
transponder was not needed, and saving them during ground operations.

Supposedly, newer solid-state transponders don't suffer from this lifetime
limitation.

Again, I'm not 100% sure on this...please feel free to correct me if I'm
wrong...




"Ross Richardson" wrote in message
...
Interesting. I always left mine in standby to allow for warm up before
going to ALT and transmitting. You mean I can just leave the sucker on
all the time? Mine is an old King KT-78.


-------------
Regards, Ross
C-172F 180HP
KSWI


Jay Masino wrote:
Ross Richardson wrote:

What do you do when requested to "recycle" your transponder?


I check to see if something isn't set correctly, but othewise I don't do
anything. Turning the transponder off and on again practically
guarantees
that it won't transmit for 30 to 45 seconds, because all modern
transponders are build to wait that long, before starting to transmit,
to
allow for warm-up.

--- Jay

"Lakeview Bill" wrote:

My understanding is that older transponders used
something called a "cavity tube" that had a relatively
short life and was expensive to replace.

Supposedly, when the transponder was on "Standby"
the cavity did not age as much as it did when "On".


Where a cavity tube is used, "standby" does not extend the life of
the tube. On any xpondr, it merely inhibits any reply pulses from
being sent to the xmit section, be it a tube or transistors.

Fred F.

On Fri, 16 Sep 2005 08:22:53 -0400, "TaxSrv" wrote
in ::

"Larry Dighera" wrote:

I don't think the transponders actually check for warmth.

A transponder contains what is termed a Crystal Oven. This is a
small
chamber in which there is a heating element and a quartz crystal
used
to determine the transponder's transmission frequency.

Which brands/models have that feature?? The frequency accuracy
required by the TSO can be and is achieved without a crystal oven.

The built-in turn-on delay is merely to allow the high-voltage
supply to come up to full volts, and the cavity tube filament to
heat up.

Fred F.


It was a long time ago that I was having difficulty with ATC receiving
the Mode-C of our King KT-78a. Now that you mention it, it was the
Mode-C blind encoder that had the heater in it, not the transponder.