---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 11/09/20: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:28 AM - Re: gps antenna under glassfibre? (bobnoffs) 2. 06:12 AM - Re: Re: gps antenna under glassfibre? (Robert L. Nuckolls, III) 3. 10:03 AM - Re: gps antenna under glassfibre? (rparigoris) 4. 01:07 PM - Re: Re: gps antenna under glassfibre? (Rowland Carson) 5. 01:33 PM - Re: Re: gps antenna under glassfibre? (Sebastien) 6. 03:31 PM - Re: Re: gps antenna under glassfibre? (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:28:06 AM PST US Subject: AeroElectric-List: Re: gps antenna under glassfibre? From: "bobnoffs" what happens if the antennas are right next to each other? it absolutely will hurt reception,or it might and it's not recommended? does anyone have experience with 2 antennas next to each other? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=499321#499321 ________________________________ Message 2 _____________________________________ Time: 06:12:16 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: gps antenna under glassfibre? At 07:26 AM 11/9/2020, you wrote: > >what happens if the antennas are right next to each other? it >absolutely will hurt reception,or it might and it's not recommended? >does anyone have experience with 2 antennas next to each other? > Receive-only antennas at near microwave frequencies are not interactive. They work fine in close proximity. Bob . . . ________________________________ Message 3 _____________________________________ Time: 10:03:01 AM PST US Subject: AeroElectric-List: Re: gps antenna under glassfibre? From: "rparigoris" Hi Rowland I have a XS mono I already had most of my antennas installed and needed to add ADS-B. The Garmin GA-35 antenna install manual wants a ground plane (Bob can't quite figure out why). Anyway I have a Dynon magnetometer in my ceiling and the GA-35 would need a clearance pocket if I did install in ceiling. Anyway I made up a 8 pointed ground plane that will also be used as an antenna mount and installing it just forward of the baggage bay bulkhead under the top of fuse. I will not install it absolute level with fuse but aim the forward up a little. Looks not too bad. https://1drv.ms/u/s!Ah1S270Nwg9V3SI7_BpEe0ECaWIV?e=cVFSGb I will bend radials fto follow the bottom of ceiling except for the front ones. The front facing radial will be ~ 2 fingers below the ceiling.Ron P. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=499323#499323 ________________________________ Message 4 _____________________________________ Time: 01:07:35 PM PST US From: Rowland Carson Subject: Re: AeroElectric-List: Re: gps antenna under glassfibre? On 2020-11-09, at 14:11, Robert L. Nuckolls, III wrote: > At 07:26 AM 11/9/2020, you wrote: >> what happens if the antennas are right next to each other? it absolutely will hurt reception,or it might and it's not recommended? does anyone have experience with 2 antennas next to each other? > Receive-only antennas at near microwave frequencies > are not interactive. They work fine in close proximity. Bob - that was my gut feeling too, but I poked around for quite some time and found this spacing chart on the Garmin marine support area: https://support.garmin.com/en-GB/marine/faq/2svIUDPSDa3M99GT2P1g09/ That was the basis for my 6/150mm spacing of the antennae already mounted on top of my instrument module. Since my earlier posting Ive been in touch with Trig support and they concur with the Garmin advice. The Trig antenna is an active device and claims 26dB gain over a passive antenna. I guess that some of the other ones are also active, and that may be at least part of the reason for the spacing requirement. Ive also slept on the question (often a good idea!) and realise that I can attach the TA50 to a small bracket above the parcel shelf (in front of the P2 seat) adjacent to the windscreen edge and that will be fine for both sky view and spacing, although perhaps not the ultimate in elegance! So, I have this day ordered a TN72/TA50 combo and look forward to getting my 50% CAA rebate on the cast. Thanks for all the thoughtful responses. in friendship Rowland | Rowland Carson ... that's Rowland with a 'w' ... | http://www.rowlandcarson.org.uk | Skype, Twitter: rowland_carson Facebook: Rowland Carson ________________________________ Message 5 _____________________________________ Time: 01:33:55 PM PST US From: Sebastien Subject: Re: AeroElectric-List: Re: gps antenna under glassfibre? Garmin, Dynon, Trig, and Stratus all state in their installation manuals that GPS antennas must be 6" apart. I have seen many, many GPS antennas sitting right next to each other working just fine but if I was building a new plane, I would try very hard to follow the installation manuals. On Mon, Nov 9, 2020 at 1:18 PM Rowland Carson wrote: > rowlandcarson@gmail.com> > > On 2020-11-09, at 14:11, Robert L. Nuckolls, III < > nuckolls.bob@aeroelectric.com> wrote: > > > At 07:26 AM 11/9/2020, you wrote: > > >> what happens if the antennas are right next to each other? it > absolutely will hurt reception,or it might and it's not recommended? does > anyone have experience with 2 antennas next to each other? > > > Receive-only antennas at near microwave frequencies > > are not interactive. They work fine in close proximity. > > Bob - that was my gut feeling too, but I poked around for quite some time > and found this spacing chart on the Garmin marine support area: > > https://support.garmin.com/en-GB/marine/faq/2svIUDPSDa3M99GT2P1g09/ > > That was the basis for my 6=9D/150mm spacing of the antennae alread y mounted > on top of my instrument module. > > Since my earlier posting I=99ve been in touch with Trig support and they > concur with the Garmin advice. The Trig antenna is an active device and > claims 26dB gain over a passive antenna. I guess that some of the other > ones are also active, and that may be at least part of the reason for the > spacing requirement. > > I=99ve also slept on the question (often a good idea!) and realise that I > can attach the TA50 to a small bracket above the parcel shelf (in front o f > the P2 seat) adjacent to the windscreen edge and that will be fine for bo th > sky view and spacing, although perhaps not the ultimate in elegance! > > So, I have this day ordered a TN72/TA50 combo and look forward to getting > my 50% CAA rebate on the cast. > > Thanks for all the thoughtful responses. > > in friendship > > Rowland > > > =========== =========== =========== =========== =========== > > ________________________________ Message 6 _____________________________________ Time: 03:31:36 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: gps antenna under glassfibre? >Since my earlier posting I=99ve been in touch >with Trig support and they concur with the >Garmin advice. The Trig antenna is an active >device and claims 26dB gain over a passive >antenna. I guess that some of the other ones are >also active, and that may be at least part of >the reason for the spacing requirement. That would be a very interesting hypothesis to explore. To be sure, there are active devices (transistors) in these devices but I cannot wrap my head around the idea that they 'radiate' any energy that would cause them to compete for real estate. Sometimes I wish I still had a desk out at Beech . . . I could often get right to the horse's mouth with a phone call to the big guys in avionics . . . King radio was always VERY helpful and forthcoming. It was King engineer that first confirmed my own studies suggesting that (1) radio killing spikes do not exist in vehicular DC power systems and (2) qualification testing of all avionics since the 80's has to PROVE that an appliance stands off EVERYTHING the airplane might throw at it. I.e. avionics master switches were ill-conceived. I might know a guy at Garmin that either knows or can find out what physics drives that spacing suggestion for non-radiating antennas. You could do the experiment yourself. Put two sets of mounting holes for the 2nd antenna . . . one 'snuggled up' to the first and the second one 'socially distanced'. See if you can observe any differences. Bob . . . ------------------------------------------------------------------------------------- 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.