Two Transponder installation Possibility

[Edwardoc]

I am about to order the SV-261 and 2020 Antenna and associated hardware to take advantage of the new rebate and have a question.  Presently have a single screen 1000  and SV-470 and and  an Appolo SL 70 transponder. Is it possible to install the 261 and somehow leave the SL-70 also hooked up as a backup?  Is it worth the effort to leave it installed after 2019 in anyones opinion?  Would you have to reconfigure the 1000 to switch from one to the other since you have to tell the 1000 what you have installed? If so kind of impractical to have both.  Comments appreciated.

 

[gtae07]

I am about to order the SV-261 and 2020 Antenna and associated hardware to take advantage of the new rebate and have a question.  Presently have a single screen 1000  and SV-470 and and  an Appolo SL 70 transponder. Is it possible to install the 261 and somehow leave the SL-70 also hooked up as a backup?  Is it worth the effort to leave it installed after 2019 in anyones opinion?  Would you have to reconfigure the 1000 to switch from one to the other since you have to tell the 1000 what you have installed? If so kind of impractical to have both.  Comments appreciated.

Ditch it. Serves no purpose with a 1090 Out system. And you don't need a backup transponder; save the weight and power for more gas and more critical systems.

 

[Garrett]

If you ground pin 17 (ext disable) on the SV-261 it will go into standby mode there probably is one on the Apollo transponder. You would not have to reconfigure the 1000 either. Just use a SPDT switch to toggle between either transponder. I have a similar setup with a Garmin 330ES so I have a backup.

 

[Raymo]

You can have two transponders but the Trig units have proven to be very reliable. I agree that the SL-70 is extra weight and could be turned into Avgas on the open market.

 

[Edwardoc]

If you ground pin 17 (ext disable) on the SV-261 it will go into standby mode there probably is one on the Apollo transponder. You would not have to reconfigure the 1000 either. Just use a SPDT switch to toggle between either transponder. I have a similar setup with a Garmin 330ES so I have a backup.

I looked over the installation and understand it now.  I think I'm just going to leave the SL 70 installed so there is no hole in the panel and install the switch to be able to put the SV-261 in standby for formation and acro.  I think I can just leave the SL-70 in standby if I turn it on so don't have to do anything special for it except to re-route the antenna lead to the SV-261 from the SL-70.  But I do have some questions.  Do I wire the 261 and SL-70 RX and TX outputs to the same pins the SL-70 is hooked to now?  And if the 261 is in standby and I turn on the SL-70, does it use the antenna output of the 261 even though it is in standby mode.  I won't have an antenna output hooked up on the SL 70 rack.  At least thats my plan.

 

[Garrett]

I am using a GTN-650 to feed my 330ES and the Dynon to feed the SV-261 each transponder with it's own output antenna. In your case if the port settings/speeds on the SL 70 and the SV-261 are the same you could use 1 double pole triple throw switch to handle the disable and RS232. And if you are going to go thru the trouble you might as well add another antenna and cable to complete the project because you cannot share the transponder cable/antenna unless you physically move it.

 

[Edwardoc]

Thats what I thought.  Will think about adding the additional antenna etc. Not sure it's worth it.

 

[Garrett]

I use the SV-261 all the time and it has worked perfectly going on 6 years. Very reliable!

 

[mmarien]

It might help you decide if it's worth keeping by running through a few scenarios where a single transponder has failed. Personally I can't think of a time or place where it would be a problem. I'm VFR so working with limited knowledge here.

I can think of a few scenarios where the second transponder could cause grief. The first is the added complexity of of the wiring, switches and antennas. It's ripe for Murphy's law.

If you need something to plug the hole, add a plaque with the common transponder codes. I've had my radio quit (7600) but not my transponder.