---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 08/05/16: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:10 AM - Re: Re: Adding a 2nd radio to my 403MC flightcom () 2. 08:38 PM - Garmin GTX 335 Install nonsense(?) (Steve Stearns) ________________________________ Message 1 _____________________________________ Time: 05:10:27 AM PST US From: Subject: Re: AeroElectric-List: Re: Adding a 2nd radio to my 403MC flightcom Thanks Joe for the input. I have a 2nd belly antenna which has coax coming into the cockpit and is set up for my handheld in case my one and only GNC3 00XL fails. It would be nice if the GNC300XL had a feature to allow monitor ing of the standby frequency but it doesn't. If I install my 2nd radio it w ould have its own antenna. Perhaps installing a 2-50 switch for the audio, on-on-(on), com 1, com 2, and using the spring loaded (on) as both audio to listen to ATIS or whatever? I know when I use to rent Cessna's, the audio panel would have a "both" switch that I would use when I wanted to listen t o ATIS without leaving the other controller. I just don't know what goes on in an audio panel that makes it safe to listen to both audios and why I co uld not do it without an audio panel? Thanks for any additional advice. =C2 - =C2- From: user9253 To: aeroelectric-list@matronics.com Sent: Thursday, August 4, 2016 7:21 PM Subject: AeroElectric-List: Re: Adding a 2nd radio to my 403MC flightcom The audio output from two radios should not be connected together without s ome kind of isolation. =C2- The audio from the second radio could connect to pin 18 on the inter com, the music aux input.=C2- But switching the intercom to "isolate" wil l disable it. =C2- Audio input on pin 21 will mute the audio input on pm 18 unless the wire connected to pin 24 is cut. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=459221#459221 - S - WIKI - - =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. ________________________________ Message 2 _____________________________________ Time: 08:38:53 PM PST US From: Steve Stearns Subject: AeroElectric-List: Garmin GTX 335 Install nonsense(?) Greetings all, I'll soon be installing a GTX335 transponder in my LongEz. The (stc) install manual has some items I find curious related to the antennas. While it does say if I'm replacing a different GTX transponder (I'm replacing a 327) the existing transponder antenna is fine, it ALSO says that the minimum radius for the transponder antenna ground plane is 12"! Mine is 2.7" (1/4 wave at 1090 MHz). Anyone have any knowledge of what they are trying to optimize? Also it goes on to say the minimum radius for the gps antenna ground plane is 7.5"! The gps antenna that goes with the GNS250XL has no ground plane at all... Anyone have any idea what they are after here? Also, the manual goes on and on about all the bonding required between antenna ground planes, the avionics rack etc. My aircraft is a LongEz (i.e. fiberglass) and I don't have any explicit "bonding" at all (though I DO have very carefully planned and implemented power returns etc. In fact, my transponder ground plane is encapsulated in fiberglass (except where it is electrically connected to the coax connector). My experience and existing knowledge tempts me to ignore all of the above but, on the other hand, I'm still learning things that surprise me everyday. Can someone enlighten me as to the technical benefits to be had by changing my existing configuration to be in line with what Garmin is mandating in their installation manual? Thanks in advance! Steve Stearns LongEz N45FC Boulder/Longmont CO ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.