On Dec 16, 6:46*pm, Eric Greenwell wrote:
Darryl Ramm wrote:
On Dec 16, 12:53 pm, Bob Kuykendall wrote:
On Dec 15, 7:46 am, Andy wrote:

...I'm quite sensitive to this at the moment as my airplane has developed
a problem that causes the mode C report to sometimes be thousands of
feet in error until the transponder or encoder warm up.
Check the encoder manual to see if the encoder has a built-in heating
coil (many do). If so, also check that it is getting power.

Thanks, Bob K.

The ACK-30 around room temperature should draw around 9mA/12V once in
steady state. Throw it in your freezer in a plastic bag and get it
really cold, with the heater warming up it should draw about 400mA/12V
(for ~minute or so).

It's not quite that good, unfortunately: according to the manual,
operating current is 60 ma; the time to warm up from 0 F is 210 seconds.
I can't find the source of the numbers, but the heater will continue to
draw heater current at 0 deg F, with a total draw around 90-100 milliamps..

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
* * * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

Oh doh, that as a typo. Should have been the 90mA no 9mA, which is
what I think I had measured but the manual says 60mA. May just depend
on ambient temp of how power consumption is averaged.

Darryl