---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 06/11/12: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:21 AM - Re: AeroElectric-List Digest: 5 Msgs - 06/10/12 (Franz Fux) 2. 06:04 AM - Re: ELT Antenna Mount (Kelly McMullen) 3. 06:51 AM - Re: ELT Antenna Mount (John Grosse) 4. 06:55 AM - BC100-1 BATTERY (David Leikam) 5. 07:20 AM - Re: BC100-1 BATTERY (William Schertz) 6. 07:24 AM - Re: ELT Antenna Mount (Stuart Hutchison) 7. 08:47 AM - Antenna Wire Disconnect at Wing Root? (Jeff Luckey) 8. 09:22 AM - Re: ELT Antenna Mount (Vern Little) 9. 09:26 AM - Re: ELT Antenna Mount (The Kuffels) 10. 10:10 AM - Re: Antenna Wire Disconnect at Wing Root? (Ralph Finch) 11. 10:11 AM - Re: Antenna Wire Disconnect at Wing Root? (Vern Little) 12. 02:11 PM - Lost my to/from flag in my VOR (joe motis) 13. 02:15 PM - Re: Antenna Wire Disconnect at Wing Root? (Fisher Paul A.) 14. 02:35 PM - Re: ELT Antenna Mount (David Lloyd) ________________________________ Message 1 _____________________________________ Time: 12:21:53 AM PST US From: "Franz Fux" Subject: AeroElectric-List: Re: AeroElectric-List Digest: 5 Msgs - 06/10/12 only intermittent access to e-mail until June 19th, in an urgent matter contact info@lastfrontierheli.com ________________________________ Message 2 _____________________________________ Time: 06:04:50 AM PST US From: Kelly McMullen Subject: Re: AeroElectric-List: ELT Antenna Mount The point is we simply don't know orientation of a crash. If on flat ground it may very well be horizontal, although I have seen a lawn dart orientation as well. In mountains, vertical is just as likely. 121.5 is no longer monitored by satellite, so only over flying aircraft are likely to detect unless crash is near ATC facility. It would be interesting to know what orientation works best with satellites. On 6/10/2012 10:23 PM, David Lloyd wrote: > > > Kelly, > I think the majority of crashes usually wind up in horizontal > orientation. If the antenna is mounted vertically in front of the > vertical stabilizer in most crashes that part of the airframe has a > good chance of staying fairly intact even upside down. > About the ELT... the older 121.5 broadcasting on the guard band is > usually not heard by a satellite but, overflying aircraft. The newer > higher band units should reach an overhead satellite. It would be > interesting to see how well the contact goes from an antenna that is > oriented horizontally and close the to earth, i.e. crash site. > I wonder if someone on the List would respond that knows the details > about the new ELT's performance under adverse conditions. > D > > _________________________________________________________________ > > ----- Original Message ----- From: "Kelly McMullen" > To: > Sent: Sunday, June 10, 2012 7:35 PM > Subject: Re: AeroElectric-List: ELT Antenna Mount > > >> >> >> How do you know what the antenna orientation will be after a crash? >> Only then will orientation matter. >> Even then, orientation to the satellite matters more than orientation >> to terrestrial receivers. >> Any mounting that prevents the antenna from being broken during the >> crash will be better than one that lets the antenna be snapped off by >> flipping the plane. >> >> On 6/10/2012 7:17 PM, David Lloyd wrote: >>> Jeff, >>> I viewed this late. Your are right, way too much signal blocking >>> structure, but, maybe even worse it is the antenna is positioned >>> horizontally. The polarization of the signal path is all wrong. It >>> must mounted vertically... >>> I am sure that you figured all this out by now.... >>> Dave >>> ------------------------------------------------------------------------ >>> >>> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> >> >> >> >> > > ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 3 _____________________________________ Time: 06:51:18 AM PST US From: John Grosse Subject: Re: AeroElectric-List: ELT Antenna Mount Whether or not the ELT works in whatever orientation you install it really only matters to me if I have a survivable crash. If my plane "lawn darts" into the ground I'm probably not gonna make it no matter what my ELT does or doesn't do. On the other hand, if my plane winds up more or less horizontal there's a good chance of my having survived and I want that thing working. The ELT manufacturers have already done the testing and the design. "Use our antenna and install according to our directions and it will work." ELT antennas are meant to be installed vertically because that's the orientation in which they work. John Grosse OBTW Haven't we gone around on this topic before? Kelly McMullen wrote: > > > The point is we simply don't know orientation of a crash. If on flat > ground it may very well be horizontal, although I have seen a lawn > dart orientation as well. In mountains, vertical is just as likely. > > ________________________________ Message 4 _____________________________________ Time: 06:55:39 AM PST US From: David Leikam Subject: AeroElectric-List: BC100-1 BATTERY I have a BC100-1 battery which was run pretty dead during paint due to the battery contractor being left on. I have tried re-charging with no luck. Is there any way to re-juvinate this battery for light use around the shop? Dave Leikam RV10 N89DA ________________________________ Message 5 _____________________________________ Time: 07:20:54 AM PST US Subject: Re: AeroElectric-List: BC100-1 BATTERY From: William Schertz If you are recharging with a "smart" charger, the charger will not work if the battery doesn't supply a minimum voltage. Try an old fashioned charger, or put it in parallel with a good battery on your smart charger. Sent from my iPad On Jun 11, 2012, at 8:54 AM, David Leikam wrote: > > I have a BC100-1 battery which was run pretty dead during paint due to the battery contractor being left on. > I have tried re-charging with no luck. Is there any way to re-juvinate this battery for light use around the shop? > > Dave Leikam > RV10 > N89DA > > > > > > > > ________________________________ Message 6 _____________________________________ Time: 07:24:12 AM PST US From: "Stuart Hutchison" Subject: RE: AeroElectric-List: ELT Antenna Mount G'day all, Kelly is right, 121.5MHz satellite monitoring was turned off in early 2009, but many airliner radios are configured to monitor GUARD 121.5 as a matter of routine. 406MHz (actually 406.025) is monitored by both a special payload on a range of geostationary (GEO) satellites and low earth orbit (LEO) satellites intended primarily for other things. The main advantage of 406 upgrade is the that the transmission is digital. Hence, your digital databurst (0.44 to 0.54 seconds long, randomised at around 50 second intervals to avoid repeated over-transmissions and TX at about 5W - much higher than the old analogue beacons) contains a bunch of useful information that the Rescue Coordination Centre can use immediately to differentiate one beacon from another (i.e you). They can then match a bunch of info to the distress, such as your flight plan. An in-built constant 121.5 swept tone generator is still required as a homing localisation signal for rescuers. 406 can be homed to, but requires specialised equipment to track the short databursts. The GEO satellites orbit the Earth, but at a rate consistent with the Earths rotation. Hence, they remain in an essentially constant position relative to the Earth, roughly overhead (about 36km up I think). A GEO satellite will generally receive your digital databurst and relay it to the RCC immediately, but can't work out where you are unless your ELT happens to transmit the GPS position as well (either in-built GPS or fed from the aircraft NAV system). The SAR situation may then be resolved immediately with a telephone call to you ... for example if the beacon is accidentally switched on. LEO satellites orbit the Earth and may also take the GPS position from your ELT, but otherwise use Doppler analysis to fix the position. However, a fix is calculated on both sides of the satellite track. A second satellite pass on a different track is required to resolve the ambiguity (i.e. there will be matching fixes to one side of the original track, but they won't match on the other side). The trouble with this is that the passes are sometimes as long as 2 hours apart, so it may take quite some time to resolve the ambiguity and determine where the ELT is transmitting from. The reason 406 is substantially more accurate to Doppler fix than the older analogue 121.5 beacons is that the standard for frequency stability is much higher. Hence, the annulus for older beacons was about 20km and for new about 5km. I recommend ELTs or Personal Locator Beacons (PLBs) with in-built GPS as they dramatically reduce the time to first accurate fix, which may matter if it's getting dark. Exposure to the elements is often the greater threat, so there's no advantage in waiting longer than you have to for rescue. Keep in mind that a great many ELTs don't work at all after a crash because the COAX gets damaged, so keep that cable run short if possible. On the up side, no matter whether you're attempting to transmit straight up to the GEO or sideways to one of the many LEO satellites, your relatively high-power databurst is likely to be detected quickly, which provides the RCC a LOT of information about you. They don't necessarily need to fix you by satellite to work out where you disappeared off radar ... but it is a huge advantage to the RCC knowing which ELT is actually transmitting !!! I have a fast two-seat tandem tailwheel with a slider canopy. There isn't much room between the canopy track and the VS, so my antenna will be bottom mounted close to the ELT inside. The antenna will be raked back at 30 degrees with a custom-made fairing around the 3/4" x 6" base. In my POV, the antenna is likely to be on top after crash landing rough enough for me to depend on it, with the 'donut' radiating towards the GEO satellite. If not, the LEOs are likely to see in due course. I also carry a GPS PLB. Hope this helps. Stu -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kelly McMullen Sent: Monday, June 11, 2012 11:03 PM Subject: Re: AeroElectric-List: ELT Antenna Mount --> The point is we simply don't know orientation of a crash. If on flat ground it may very well be horizontal, although I have seen a lawn dart orientation as well. In mountains, vertical is just as likely. 121.5 is no longer monitored by satellite, so only over flying aircraft are likely to detect unless crash is near ATC facility. It would be interesting to know what orientation works best with satellites. On 6/10/2012 10:23 PM, David Lloyd wrote: > > > Kelly, > I think the majority of crashes usually wind up in horizontal > orientation. If the antenna is mounted vertically in front of the > vertical stabilizer in most crashes that part of the airframe has a > good chance of staying fairly intact even upside down. > About the ELT... the older 121.5 broadcasting on the guard band is > usually not heard by a satellite but, overflying aircraft. The newer > higher band units should reach an overhead satellite. It would be > interesting to see how well the contact goes from an antenna that is > oriented horizontally and close the to earth, i.e. crash site. > I wonder if someone on the List would respond that knows the details > about the new ELT's performance under adverse conditions. > D > > _________________________________________________________________ > > ----- Original Message ----- From: "Kelly McMullen" > > To: > Sent: Sunday, June 10, 2012 7:35 PM > Subject: Re: AeroElectric-List: ELT Antenna Mount > > >> >> >> How do you know what the antenna orientation will be after a crash? >> Only then will orientation matter. >> Even then, orientation to the satellite matters more than orientation >> to terrestrial receivers. >> Any mounting that prevents the antenna from being broken during the >> crash will be better than one that lets the antenna be snapped off by >> flipping the plane. >> >> On 6/10/2012 7:17 PM, David Lloyd wrote: >>> Jeff, >>> I viewed this late. Your are right, way too much signal blocking >>> structure, but, maybe even worse it is the antenna is positioned >>> horizontally. The polarization of the signal path is all wrong. It >>> must mounted vertically... >>> I am sure that you figured all this out by now.... >>> Dave >>> -------------------------------------------------------------------- >>> ---- >>> >>> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> >> >> >> >> > > ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 7 _____________________________________ Time: 08:47:30 AM PST US From: "Jeff Luckey" Subject: AeroElectric-List: Antenna Wire Disconnect at Wing Root? I'm planning wire runs for wings on RV-7 and would like to make wings as easy to remove as possible. Planning on using Molex-like connectors at wing roots for lights in the wing. Also planning to use wing-tip VOR antenna from Bob Archer. Question: 1. How much loss would I encounter if I use a coax connector at the wing root for the VOR antenna? 2. What is the best-we-know-how-to-do for this issue? Thanks, Jeff Luckey ________________________________ Message 8 _____________________________________ Time: 09:22:41 AM PST US From: "Vern Little" Subject: Re: AeroElectric-List: ELT Antenna Mount Great technical comparison. One thing about 406 (and other VHF/UHF frequencies) is that radio waves tend to bounce around off of metal/water/rock rather than be absorbed. I'm not an RF guy, but this effect is seen when using a cellphone in an elevator (effectively a Faraday cage with small openings for radio waves to leak out). Is there anything about 406 MHz that makes it better in the SAR application due to this effect? What I'm getting at, is does it really matter what polarization is, or adjacency to metal objects is in a real-world application.... the signal might just bounce around until it 'leaks out' to the satellite? Vern -----Original Message----- From: Stuart Hutchison Sent: Monday, June 11, 2012 7:23 AM Subject: RE: AeroElectric-List: ELT Antenna Mount G'day all, Kelly is right, 121.5MHz satellite monitoring was turned off in early 2009, but many airliner radios are configured to monitor GUARD 121.5 as a matter of routine. 406MHz (actually 406.025) is monitored by both a special payload on a range of geostationary (GEO) satellites and low earth orbit (LEO) satellites intended primarily for other things. The main advantage of 406 upgrade is the that the transmission is digital. Hence, your digital databurst (0.44 to 0.54 seconds long, randomised at around 50 second intervals to avoid repeated over-transmissions and TX at about 5W - much higher than the old analogue beacons) contains a bunch of useful information that the Rescue Coordination Centre can use immediately to differentiate one beacon from another (i.e you). They can then match a bunch of info to the distress, such as your flight plan. An in-built constant 121.5 swept tone generator is still required as a homing localisation signal for rescuers. 406 can be homed to, but requires specialised equipment to track the short databursts. The GEO satellites orbit the Earth, but at a rate consistent with the Earths rotation. Hence, they remain in an essentially constant position relative to the Earth, roughly overhead (about 36km up I think). A GEO satellite will generally receive your digital databurst and relay it to the RCC immediately, but can't work out where you are unless your ELT happens to transmit the GPS position as well (either in-built GPS or fed from the aircraft NAV system). The SAR situation may then be resolved immediately with a telephone call to you ... for example if the beacon is accidentally switched on. LEO satellites orbit the Earth and may also take the GPS position from your ELT, but otherwise use Doppler analysis to fix the position. However, a fix is calculated on both sides of the satellite track. A second satellite pass on a different track is required to resolve the ambiguity (i.e. there will be matching fixes to one side of the original track, but they won't match on the other side). The trouble with this is that the passes are sometimes as long as 2 hours apart, so it may take quite some time to resolve the ambiguity and determine where the ELT is transmitting from. The reason 406 is substantially more accurate to Doppler fix than the older analogue 121.5 beacons is that the standard for frequency stability is much higher. Hence, the annulus for older beacons was about 20km and for new about 5km. I recommend ELTs or Personal Locator Beacons (PLBs) with in-built GPS as they dramatically reduce the time to first accurate fix, which may matter if it's getting dark. Exposure to the elements is often the greater threat, so there's no advantage in waiting longer than you have to for rescue. Keep in mind that a great many ELTs don't work at all after a crash because the COAX gets damaged, so keep that cable run short if possible. On the up side, no matter whether you're attempting to transmit straight up to the GEO or sideways to one of the many LEO satellites, your relatively high-power databurst is likely to be detected quickly, which provides the RCC a LOT of information about you. They don't necessarily need to fix you by satellite to work out where you disappeared off radar ... but it is a huge advantage to the RCC knowing which ELT is actually transmitting !!! I have a fast two-seat tandem tailwheel with a slider canopy. There isn't much room between the canopy track and the VS, so my antenna will be bottom mounted close to the ELT inside. The antenna will be raked back at 30 degrees with a custom-made fairing around the 3/4" x 6" base. In my POV, the antenna is likely to be on top after crash landing rough enough for me to depend on it, with the 'donut' radiating towards the GEO satellite. If not, the LEOs are likely to see in due course. I also carry a GPS PLB. Hope this helps. Stu -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kelly McMullen Sent: Monday, June 11, 2012 11:03 PM Subject: Re: AeroElectric-List: ELT Antenna Mount --> The point is we simply don't know orientation of a crash. If on flat ground it may very well be horizontal, although I have seen a lawn dart orientation as well. In mountains, vertical is just as likely. 121.5 is no longer monitored by satellite, so only over flying aircraft are likely to detect unless crash is near ATC facility. It would be interesting to know what orientation works best with satellites. On 6/10/2012 10:23 PM, David Lloyd wrote: > > > Kelly, > I think the majority of crashes usually wind up in horizontal > orientation. If the antenna is mounted vertically in front of the > vertical stabilizer in most crashes that part of the airframe has a > good chance of staying fairly intact even upside down. > About the ELT... the older 121.5 broadcasting on the guard band is > usually not heard by a satellite but, overflying aircraft. The newer > higher band units should reach an overhead satellite. It would be > interesting to see how well the contact goes from an antenna that is > oriented horizontally and close the to earth, i.e. crash site. > I wonder if someone on the List would respond that knows the details > about the new ELT's performance under adverse conditions. > D > > _________________________________________________________________ > > ----- Original Message ----- From: "Kelly McMullen" > > To: > Sent: Sunday, June 10, 2012 7:35 PM > Subject: Re: AeroElectric-List: ELT Antenna Mount > > >> >> >> How do you know what the antenna orientation will be after a crash? >> Only then will orientation matter. >> Even then, orientation to the satellite matters more than orientation >> to terrestrial receivers. >> Any mounting that prevents the antenna from being broken during the >> crash will be better than one that lets the antenna be snapped off by >> flipping the plane. >> >> On 6/10/2012 7:17 PM, David Lloyd wrote: >>> Jeff, >>> I viewed this late. Your are right, way too much signal blocking >>> structure, but, maybe even worse it is the antenna is positioned >>> horizontally. The polarization of the signal path is all wrong. It >>> must mounted vertically... >>> I am sure that you figured all this out by now.... >>> Dave >>> -------------------------------------------------------------------- >>> ---- >>> >>> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> >> >> >> >> > > ----- No virus found in this message. Checked by AVG - www.avg.com ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 9 _____________________________________ Time: 09:26:50 AM PST US From: "The Kuffels" Subject: Re: AeroElectric-List: ELT Antenna Mount It has been almost 50 years since I worked for an antenna company but I do have substantial real-world experience with ELTs. Antenna orientation doesn't matter in this application. You have on the order of over 100 db of signal loss before communication with a satellite becomes difficult. Antenna orientation will cause at most 3 db of signal loss. A much more important factor is antenna/cable integrity. In a relatively minor crash almost any location will work. At worst you can remove the ELT and jury rig a workable antenna. In a major crash (you're trapped, won't survive long, etc) there is a high likelihood *any* external ELT antenna will be disconnected. This is why I advocate ELT antennas be mounted internally. Bad radio location but a lot better than non-existent. For fiberglass structure a good location is in the forward part of the tail cone. For carbon fiber and metal planes you should mount it somewhere in the cabin with a view outside. For bubble canopies this is easy but even high-wing and tube structures will work from inside. The 406 MHz signal will pass through any gap larger than 5 inches. Even the non-essential 121.5 MHz signal will be detectable from short distances no matter what pile of metal randomly surrounds the antenna. Tom Kuffel ________________________________ Message 10 ____________________________________ Time: 10:10:37 AM PST US From: Ralph Finch Subject: Re: AeroElectric-List: Antenna Wire Disconnect at Wing Root? >From everything I've heard it's very difficult to remove wings once installed with the close-tolerance bolts. Nevertheless I installed connectors for all wiring at the wing roots so I could wire the wings and fuselage ahead of time separately, and connect them at the time I joined wings to fuselage. I believe there is very little loss for a single coax connector. Ralph Finch On Mon, Jun 11, 2012 at 8:45 AM, Jeff Luckey wrote: > I=92m planning wire runs for wings on RV-7 and would like to make wings as > easy to remove as possible.**** > > ** ** > > Planning on using Molex-like connectors at wing roots for lights in the > wing. **** > > Also planning to use wing-tip VOR antenna from Bob Archer. **** > > ** ** > > Question:**** > > ** ** > > 1. How much loss would I encounter if I use a coax connector at the wing > root for the VOR antenna?**** > > 2. What is the best-we-know-how-to-do for this issue?**** > > ** ** > > ** ** > > Thanks,**** > > ** ** > > Jeff Luckey**** > > ** ** > > * > =========== =========== =========== =========== > * > > ________________________________ Message 11 ____________________________________ Time: 10:11:18 AM PST US From: "Vern Little" Subject: Re: AeroElectric-List: Antenna Wire Disconnect at Wing Root? Removing the wings from an RV is not an easy process. Wiring will be the least concern if this is necessary. What I did on my first RV was to use terminal blocks and bnc connectors, but in my Rocket, I=99m just going to connect the wires with butt splices and the antenna wire will be routed without interruption to the panel. With a bit of slack or a service loop, if you ever have to remove the wings, cut the wires and reterminate with new butt splices. As for the antenna cables, you can then add bnc in-line connectors. This is by far the cheapest, easiest, lightest and most space efficient solution. Also, connectors of any kind are failure points that eventually will need service. I=99ve had more connector failures in my career than the I care to discuss. Vern From: Jeff Luckey Sent: Monday, June 11, 2012 8:45 AM Subject: AeroElectric-List: Antenna Wire Disconnect at Wing Root? I=99m planning wire runs for wings on RV-7 and would like to make wings as easy to remove as possible. Planning on using Molex-like connectors at wing roots for lights in the wing. Also planning to use wing-tip VOR antenna from Bob Archer. Question: 1. How much loss would I encounter if I use a coax connector at the wing root for the VOR antenna? 2. What is the best-we-know-how-to-do for this issue? Thanks, Jeff Luckey No virus found in this message. Checked by AVG - www.avg.com 06/11/12 ________________________________ Message 12 ____________________________________ Time: 02:11:47 PM PST US Subject: AeroElectric-List: Lost my to/from flag in my VOR From: joe motis The needle still swings but the flag does not drop. Just trying to educate myself a bit before it goes into the shop. It is a KX 155 radio. Anyone have this issue ? Thanks Joe Motis Cherokee 180E ________________________________ Message 13 ____________________________________ Time: 02:15:10 PM PST US From: "Fisher Paul A." Subject: RE: AeroElectric-List: Antenna Wire Disconnect at Wing Root? Jeff, As several others have said - "the best we know how to do" is don't plan to take the wings back off! Once you permanently install them, you will unde rstand! ;-) However to answer your question, I had exactly the same thought you did - m ake it easy to remove later. I put a bulkhead BNC connector on the side of the fuselage for the VOR antenna in the wingtip and it works fine. I've ha d no issues with it (VOR, localizer, and glideslope). I can't speak to the amount of loss - I don't have the equipment or expertise to give you a num ber. But I can tell you that it has worked for the last three years and I have no plans to change it. Hope that helps. Paul A. Fisher RV-7A N18PF ~330 hours since August of 2009 From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectr ic-list-server@matronics.com] On Behalf Of Jeff Luckey Sent: Monday, June 11, 2012 10:46 AM Subject: AeroElectric-List: Antenna Wire Disconnect at Wing Root? I'm planning wire runs for wings on RV-7 and would like to make wings as ea sy to remove as possible. Planning on using Molex-like connectors at wing roots for lights in the win g. Also planning to use wing-tip VOR antenna from Bob Archer. Question: 1. How much loss would I encounter if I use a coax connector at the wing ro ot for the VOR antenna? 2. What is the best-we-know-how-to-do for this issue? Thanks, Jeff Luckey ________________________________ Message 14 ____________________________________ Time: 02:35:40 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: ELT Antenna Mount Tom, Great review and what I was hoping would show up on the List...... Thanks, D ___________________________________________________ ----- Original Message ----- From: "The Kuffels" Sent: Monday, June 11, 2012 9:25 AM Subject: Re: AeroElectric-List: ELT Antenna Mount > > > It has been almost 50 years since I worked for an antenna company but I do > have substantial real-world experience with ELTs. > > Antenna orientation doesn't matter in this application. You have on the > order of over 100 db of signal loss before communication with a satellite > becomes difficult. Antenna orientation will cause at most 3 db of signal > loss. A much more important factor is antenna/cable integrity. In a > relatively minor crash almost any location will work. At worst you can > remove the ELT and jury rig a workable antenna. In a major crash (you're > trapped, won't survive long, etc) there is a high likelihood *any* > external ELT antenna will be disconnected. > > This is why I advocate ELT antennas be mounted internally. Bad radio > location but a lot better than non-existent. For fiberglass structure a > good location is in the forward part of the tail cone. For carbon fiber > and metal planes you should mount it somewhere in the cabin with a view > outside. For bubble canopies this is easy but even high-wing and tube > structures will work from inside. The 406 MHz signal will pass through > any gap larger than 5 inches. Even the non-essential 121.5 MHz signal > will be detectable from short distances no matter what pile of metal > randomly surrounds the antenna. > > Tom Kuffel > > > ------------------------------------------------------------------------------------- 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.