old transponders

[coffeeguy]

I was talking with an avionics guy yesterday and we were talking about using my existing transponder and something like the uavionix skybeacon. He said that the older tube transponders had a variance of +/- 5% and if you pulled one out of your plane and looked at it on the scope it was probably worse. Apparently the new spec is +/- 1% and this could cause problems. I'm sure that he would like to sell me new equipment and installation services to put it in my Cherokee (my 14 won't be done by 2020), but is this a problem people are running into?

[DennisRhodes]

The used market has got a pretty good supply of Mode C transponders, many of which are digital and by most, considered fairly new. It's just that the Mode S and ES xponders are what seems to be the route many are going for 2020 compliance. You can upgrade your old tube Transponder to say a used Garmin 320 or 327 for less than $500, especially if your plan was to install a UAT ADS-B unit like the Beacon, Freeflight or uAvonix or others. They will work great for that service. The price hit the bottom on the Mode C units about a year ago and now not a bad choice if that fits the type of flying you normally do.

[coffeeguy]

Thanks, I normally fly within an hour of my home base to uncontrolled or class d airports, but I live just under the O'Hare mode C ring, so I have to comply or move the plane. I'm just looking to comply so I can keep my plane 10 minutes from home.

[BobTurner]

As already noted, good used 327s are going for as little as $400. You probably pay half that much to have your current one re-certified every two years, with a good chance it will fail (and then cost more to fix).

[wera710]

Jeff, I just got back my PAPR report and the numbers were outstanding when you consider I am using a god-knows-how-old old KT-76A transponder and a Mode C encoder to talk to my Uavionix EchoUAT ADS-B system. Needless to say, the Uavoinix system was able to get everything it needed to generate a solid report with 0 errors. So, unless you really are committed to updating your panel with the latest toys, I'd also recommend just getting a good used KT-76A or similar generation system with a made C encoder.

Heck, the way RV guys are throwing away "old" tech for shiny glass everything, you can probably scrape one up for free around here if you beg loud enough.