Marcelo Posted September 7, 2021 Report Share Posted September 7, 2021 I have a GTR 200, everything was working fine until a few months ago. The radio started to have low reception, I receive communications at short distance very well, but as I move away from the emitting source, the sound becomes low to the point where it doesn't open the squech. If I open squech manually I can hear the ATC (for example) very low transmitting. Recently I noticed the monitoring frequency has a much better reception through the following test: far from the ATC (at least 60nm) I had RX on the monitoring frequency, changed to main frequency and stopped receiving, in the next second I returned the frequency for monitoring and I received it again. Which leads to the conclusion that the main frequency has low receptivity but the one being monitored does not. Strange because it's usually the same circuit that does this. I couldn't find the radio scheme to confirm. To conclude, I already took the radio to a specialist for a test, there was no problem. Quote Link to comment Share on other sites More sharing options...
GrassStripFlyBoy Posted September 7, 2021 Report Share Posted September 7, 2021 This post may be helpful, besides the noise issues RX was weak. Radio Noise - General Avionics - CT Flier Forum Quote Link to comment Share on other sites More sharing options...
Madhatter Posted September 7, 2021 Report Share Posted September 7, 2021 I've been working with avionics for a long time, even had a certified avionics repair station for many years. I have always found most problems occur with the installation, wires , coax, especially grounds. It doesn't take much to have an issue. Sometimes it's easier to just rewire the entire radio. Unlike with older equipment the new technology radio and navigation equipment is very intolerant of just attaching a wire . There are very specific lengths and routings that have to be adhered to and requires detailed attention, it's in the installation manual. If your radio bench checks ok my bet is on installation. Most installations that are done other than at a repair station are poorly done. Not only that but the factory installations and general airframe wiring for CT are atrocious, amateur at best ( at least on mine). Most A&P's are not avionics qualified, it's a skill that takes a long time and is not taught in A&P school. Quote Link to comment Share on other sites More sharing options...
Jacques Posted September 7, 2021 Report Share Posted September 7, 2021 2 hours ago, Madhatter said: ".........but the factory installations and general airframe wiring for CT are atrocious, amateur at best ....." agree 200% Quote Link to comment Share on other sites More sharing options...
Anticept Posted September 7, 2021 Report Share Posted September 7, 2021 4 hours ago, Madhatter said: I've been working with avionics for a long time, even had a certified avionics repair station for many years. I have always found most problems occur with the installation, wires , coax, especially grounds. It doesn't take much to have an issue. Sometimes it's easier to just rewire the entire radio. Unlike with older equipment the new technology radio and navigation equipment is very intolerant of just attaching a wire . There are very specific lengths and routings that have to be adhered to and requires detailed attention, it's in the installation manual. If your radio bench checks ok my bet is on installation. Most installations that are done other than at a repair station are poorly done. Not only that but the factory installations and general airframe wiring for CT are atrocious, amateur at best ( at least on mine). Most A&P's are not avionics qualified, it's a skill that takes a long time and is not taught in A&P school. Not to mention the required testing equipment to confirm. The connection can LOOK fine, ohm out fine, but when put in service, they don't work well. The higher the frequency, the less tolerant to imperfections that the device will be. This is true in the I.T. world with networking too. Oh the number of times that I found the cause of a problem to be a bad cable... Quote Link to comment Share on other sites More sharing options...
Marcelo Posted September 14, 2021 Author Report Share Posted September 14, 2021 I could confirm this weekend the problem is on the main frequency, the monitoring frequency works properly. I will try to update the firmware and get support from Garmim. Quote Link to comment Share on other sites More sharing options...
Marcelo Posted April 23, 2022 Author Report Share Posted April 23, 2022 Hello there, Sharing the solution found! It's not solve with firmware update. The input Voltage Range of Garmin GTR 200 is 14/28 VDC (checked in manual), but rotax engine reach only a peak of 13.7v, so I have installed an DC converter 12v to 24v only to radio power and now I have good RX (reception). I heard that Lycoming engines, even though, 12v dont have this problem, but Rotax has. Thanks by help, have a good flights! Quote Link to comment Share on other sites More sharing options...
Madhatter Posted April 23, 2022 Report Share Posted April 23, 2022 13.7 volts is just fine, there's another issue going on. Quote Link to comment Share on other sites More sharing options...
Marcelo Posted April 24, 2022 Author Report Share Posted April 24, 2022 21 hours ago, Madhatter said: 13.7 volts is just fine, there's another issue going on. Maybe sometimes not. In my case, after change the voltage to 24v my radio survive. An unofficial comment that GTR 200 below 14v reduce RX "sensibility", or be, works but not with all power. But the most important information is the manual shows 14v/28v. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted April 24, 2022 Report Share Posted April 24, 2022 14/28 is only a reference to what voltage category the radio falls into. Quote Link to comment Share on other sites More sharing options...
Marcelo Posted July 3, 2023 Author Report Share Posted July 3, 2023 Yes @Madhatter, you were right. The issue persists, and I'm starting a new round of research to find the solution. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted July 4, 2023 Report Share Posted July 4, 2023 Just take it to an avionics shop and have it benched checked. That will identify where the issue is. It's very simple to do. Quote Link to comment Share on other sites More sharing options...
Frank Posted October 21, 2023 Report Share Posted October 21, 2023 I have the same issue as Marcelo identified, receiving standby with monitor further out than if I flipped it to active. Any update or solution? Quote Link to comment Share on other sites More sharing options...
Madhatter Posted October 22, 2023 Report Share Posted October 22, 2023 There is a software update to version 3.50 which corrects some monitor issues. Quote Link to comment Share on other sites More sharing options...
Marcelo Posted October 25, 2023 Author Report Share Posted October 25, 2023 On 10/21/2023 at 5:18 PM, Frank said: I have the same issue as Marcelo identified, receiving standby with monitor further out than if I flipped it to active. Any update or solution? I updated the software, and no improvement was noted, unfortunately. Quote Link to comment Share on other sites More sharing options...
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