---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Wed 11/19/08: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:58 PM - Re: ARTEX 406 ELT in a 7A (bcollinsmn) 2. 09:18 PM - 406 MHz ELT (DEAN PSIROPOULOS) 3. 10:10 PM - Re: 406 MHz ELT (Tom Gummo) ________________________________ Message 1 _____________________________________ Time: 05:58:35 PM PST US Subject: RV-List: Re: ARTEX 406 ELT in a 7A From: "bcollinsmn" So, umm, back to the original question. Does anyone have any images of their antenna installation for this configuration. Just curious. Thanks. -------- Bob Collins St. Paul, Minn. RV-7A (#&^ fiberglass!) http://rvbuildershotline.com Day job: http://minnesota.publicradio.org/collections/special/columns/news_cut/ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=215192#215192 ________________________________ Message 2 _____________________________________ Time: 09:18:07 PM PST US From: "DEAN PSIROPOULOS" Subject: RV-List: 406 MHz ELT Just in front of the vertical stab is still a very good location (mine is about 18 inches forward of the vertical stab). Since the vertical stabilizer is quite narrow and parallel to the antenna there will be very little interference or reflection off of the leading edge. It's the folks who have mounted the ELT antenna underneath the fiberglas tail intersection fairing that are really limiting their usefulness. In that location the antenna is mounted horizontally on the aft turtle deck bulkhead (RV-6/7/9) projecting out into the 90 degree corner created by the intersection of the vertical and horizontal stabilizers. That creates an excellent waveguide effect, blocking the signal from reaching half of the area on the other side of the aircraft. Jerry, I understand the thinking about putting the antenna on the bottom and it's another one of those multitude of "what if" scenarios that we RV builders run through our heads so many times while we're building. I guess to answer that somebody has to do some research on how many downed RVs have ended up on their backs. I have heard of several but don't know just what percentage of ALL RV accidents they actually make up. If you put it under the wing and you stay right side up in a crash, you will be attenuating a good bit of the signal and shortening the range at which you can be detected. If you put it between the trailing edge of the wing and the forward edge of the horizontal stab (top or bottom of fuselage) your range should be quite good (right side up or upside down). Then you have to start thinking about how to keep the antenna from being ripped off in the crash (Tim Bryan's idea). And so the thought process goes... sometimes being a safety analyst makes my brain hurt but, more food for thought. Dean Psiropoulos RV-6A N197DM > -----Original Message----- From: "Tim Bryan" Subject: RE: RV-List: 406 MHz ELT I have my antenna mounted just in front of the vertical stabilizer. My thinking was in a rollover the stabilizer *might* protect the antenna from being smashed. Now I am wondering if the stabilizer causes any shielding of the signal. Dean, any thoughts on that? Tim Bryan RV-6 Flying N616TB over 100 hours now ________________________________ Message 3 _____________________________________ Time: 10:10:34 PM PST US From: "Tom Gummo" Subject: Re: RV-List: 406 MHz ELT Dean and all, I would like to add one more thought about where to put the ELT antenna. It shouldn't be what percentage land on their backs but ... If the plane stay upright, there is a great chance that I am relatively OK, and the ELT will be the least of my problems, however, if the plane ends up on its back, then the crash was not controlled and there will be a good chance that I am NOT OK. And any help the ELT can be might make all the difference. Of course, there is no good answer for crashing. And remember most things on the ground are harder than your plane. :-( Lets hope no one has need of their ELT. GummiBear Air Force Chief of Safety at Incirlik AB, Turkey (many years ago) ----- Original Message ----- From: "DEAN PSIROPOULOS" Sent: Wednesday, November 19, 2008 9:15 PM Subject: RV-List: 406 MHz ELT > > > Just in front of the vertical stab is still a very good location (mine is > about 18 inches forward of the vertical stab). Since the vertical > stabilizer is quite narrow and parallel to the antenna there will be very > little interference or reflection off of the leading edge. It's the folks > who have mounted the ELT antenna underneath the fiberglas tail > intersection > fairing that are really limiting their usefulness. In that location the > antenna is mounted horizontally on the aft turtle deck bulkhead (RV-6/7/9) > projecting out into the 90 degree corner created by the intersection of > the > vertical and horizontal stabilizers. That creates an excellent waveguide > effect, blocking the signal from reaching half of the area on the other > side > of the aircraft. > > Jerry, I understand the thinking about putting the antenna on the bottom > and > it's another one of those multitude of "what if" scenarios that we RV > builders run through our heads so many times while we're building. I > guess > to answer that somebody has to do some research on how many downed RVs > have > ended up on their backs. I have heard of several but don't know just what > percentage of ALL RV accidents they actually make up. If you put it under > the wing and you stay right side up in a crash, you will be attenuating a > good bit of the signal and shortening the range at which you can be > detected. If you put it between the trailing edge of the wing and the > forward edge of the horizontal stab (top or bottom of fuselage) your range > should be quite good (right side up or upside down). Then you have to > start > thinking about how to keep the antenna from being ripped off in the crash > (Tim Bryan's idea). And so the thought process goes... sometimes being a > safety analyst makes my brain hurt but, more food for thought. > > Dean Psiropoulos > RV-6A N197DM > > >> -----Original Message----- > From: "Tim Bryan" > Subject: RE: RV-List: 406 MHz ELT > > I have my antenna mounted just in front of the vertical stabilizer. My > thinking was in a rollover the stabilizer *might* protect the antenna from > being smashed. Now I am wondering if the stabilizer causes any shielding > of > the signal. Dean, any thoughts on that? > > Tim Bryan > RV-6 Flying > N616TB over 100 hours now > > > __________ Information from ESET NOD32 Antivirus, version of virus > signature database 3626 (20081119) __________ > > The message was checked by ESET NOD32 Antivirus. > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV-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/rv-list Browse Digests http://www.matronics.com/digest/rv-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.