Transponder squawk wrong

[hydroguy2]

On our recent trip to Utah, I requested flight following. Salt Lake Center said to squawk 6201(or something like that) I dialed in 6201 on my Garmin 320. A few minutes later Center says N155BK we're showing 3201 for you, check your transponder. I turned it off and back on, pressed indent...but no change. They said that's okay, just leave it there. Did the same thing on the return trip.

I have an appointment with Aerotronics in Billings next week to get it all checked, but am wondering....what might be wrong? Is this a normal failure mode for transponders?

[BobTurner]

Not uncommon. The code is binary, so 6= 4+2+1; 3=2+1. Your 4 bit is out.

[Joe]

Originally Posted by hydroguy2

....what might be wrong? Is this a normal failure mode for transponders?

Might be a simple case of a bad mechanical rotary switch contact (slight corrosion) due to lack of use (i.e. the transponder spends all of its time squawking 1200).

With the transponder in "SBY", you might try cycling each switch from 0 through 7 several times,, then squawk "ALT" and see if the problem has cleared up.

--
Joe

[hydroguy2]

Thanks guys. I'm hoping to fly to work tomorrow so maybe I'll spin the knobs around for a while.

I could hook my cordless drill to it and generate some friction.

[rv8bldr]

Originally Posted by BobTurner

Not uncommon. The code is binary, so 6= 4+2+1; 3=2+1. Your 4 bit is out.

4+2+1 is 6?

[flion]

Originally Posted by rv8bldr

4+2+1 is 6?

The 1 is silent.

[Snowflake]

You were trying to send a 6, which is 4+2, and you were actually sending 3, which is 2+1. Something has spun in your selector, I suspect. Or put another way, shift happens.

[WingsOnWheels]

I'm sorry, all I can think of now is the movie Clue: 1+2+1+1

Wadsworth: The game's up, Scarlet. There are no more bullets left in that gun.

Miss Scarlet: Oh, come on, you don't think I'm gonna fall for that old trick?

Wadsworth: It's not a trick. There was one shot at Mr. Boddy in the Study; two for the chandelier; two at the Lounge door and one for the singing telegram.

Miss Scarlet: That's not six.

Wadsworth: One plus two plus two plus one.

Miss Scarlet: Uh-uh, there was only one shot that got the chandelier. That's one plus two plus *one* plus one.

Wadsworth: Even if you were right, that would be one plus one plus two plus one, not one plus *two* plus one plus one.

Miss Scarlet: Okay, fine. One plus two plus one... Shut up! The point is, there is one bullet left in this gun and guess who's gonna get it!

[jjconstant]

Originally Posted by Snowflake

You were trying to send a 6, which is 4+2, and you were actually sending 3, which is 2+1. Something has spun in your selector, I suspect. Or put another way, shift happens.

Today, it's "ship" happens

[Mike S]

Originally Posted by jjconstant

Today, it's "ship" happens

Beat me to it.