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erratic Mode C from Ameri-King 350 Encoder

A

alcladrv

Well Known Member
In flying my -7A today, ATC reported that my Mode C output would jump randomly from 2800 to 3000 to 2600 to XXX(no altitude readout) to 2800, etc. It wasn't very turbulent and I was able to maintain my altimeter within a 100 feet of 3000 during the whole time.

Has anyone experienced the same thing? Does anyone have any trouble-shooting ideas? Thanks,

Mike
 
Mike

I had a similar problem with an AK-350. One of the gray code output lines to the transponder (B4 I think) was stuck Low. This caused the transponder to show correct altitude at some altitudes and blank out or worse, the wrong altitude at some altitudes.
I got an ACK A-30 to replace the 350 and it works great. The pinout is the same and it has RS-232 outputs if you can use a digital output.

God luck

Paul Danclovic
Carver MN/Albuquerque NM
RV-8A Flying
 
Quick question for similar hiccup that my friend and I noticed on his LSA just this week as we travel around the islands of Corsica and Sardinia.

ATC was reading 6200ft instead of the 7500ft (or better, FL75 since we change to 29.92/1013.2 above 6000' in that area), so I've declared my mode C INOP and switched off ALT reporting and reverted to simple mode A reporting.

But how can I troubleshoot the Gray-encoded lines from the blind encoder?

Does anyone know about a simple board that would accept Gray-encoded lines and somehow display the reported Pressure Altitude that the transponder then sends back to ATC? My Microair T2000 has that function in its firmware, but the old Narco that my friend has does not.

Many thanks,

Luca
 
Me too

alcladrv said:
In flying my -7A today, ATC reported that my Mode C output would jump randomly from 2800 to 3000 to 2600 to XXX(no altitude readout) to 2800, etc. It wasn't very turbulent and I was able to maintain my altimeter within a 100 feet of 3000 during the whole time.

Has anyone experienced the same thing? Does anyone have any trouble-shooting ideas? Thanks,

Mike
Click to expand...

Hi Mike,
I've had mine readjusted by an avionics shop twice already for misreporting my altitude. The shop owner said that the encoder should be replaced with a better one if it does it again.......he really doesn't like this brand,

Sorry,
Pierre
 
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