Transponder not reliable 2-10 miles east of CYTZ

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Derek
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Transponder not reliable 2-10 miles east of CYTZ

Post by Derek »

Has anyone experienced this problem and can suggest a fix? My local airport, CYTZ, had trouble reading the original transponder on my 2001 DA 20. I had the unit checked and it was fine so I had the antenna replaced which didn’t fix the problem. So I replaced the transponder with an adsb in/out model and the problem seemed to be resolved. 2 years later the tower is now saying my new transponder is intermittent again. It only happens just east of Toronto at lower altitudes (around 2,500 or below, which is where I have to be to avoid bigger traffic). It seems like the plane transmits a weaker signal than it should and it’s being blanketed by the tall buildings in the downtown core. The control tower says they have had other planes with the same problem but mine is the worst. Argh! Any suggestions? I’ve already replaced the whole transponder and the antenna.
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Steve
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Re: Transponder not reliable 2-10 miles east of CYTZ

Post by Steve »

Last component in the system - cable? Have you had the transponder output checked as part of the biennial recert?
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Lou
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Re: Transponder not reliable 2-10 miles east of CYTZ

Post by Lou »

I had this too - intermittent dropping out, and then it would come back with a recycle. No problem since I got the GTX345, but then it happened once a couple weeks ago.

It may be a combination of weak localized reception for a ground station combined with a slightly weak signal from the aircraft. Probably almost impossible to troubleshoot. Let us know how you make out - these problems can drive a person mad.
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Derek
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Re: Transponder not reliable 2-10 miles east of CYTZ

Post by Derek »

Transponder always passes the cert, that’s why the avionics shop decided to go for a new antenna as a first step. New transponder hasn’t been retested yet as I just got it a year ago. It’s definitely better than the old one but obviously not perfect. Good idea to try a new cable next as it’s presumably the last part of the system to change out.

I was back into the same airport twice over the weekend and there were no issues - tower says they had a good signal the whole time. Again, its only happening at the one airport when approaching from the east at a low-ish altitude. I feel like it’s as much their equipment / location problem as mine but I don’t want something dangerous to happen while we work through this.
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Colin
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Re: Transponder not reliable 2-10 miles east of CYTZ

Post by Colin »

Watch the temperature when it is failing. I had failures every time I was at KICT crossing the country. Then I realized that it was the summer crossings. It turned out that the cooling for the LRU was pretty poor and after a *lot* of careful tinkering with customizing how the airflow worked, Dave at Premier's shop in Ft. Worth finally got it fixed. No problems since.
Colin Summers, PP Multi-Engine IFR, ~3,000hrs
colin@mightycheese.com * send email rather than PM
http://www.flyingsummers.com
N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
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