AeroElectric-List Digest Archive

Sat 05/27/06


Total Messages Posted: 9



Today's Message Index:
----------------------
 
     1. 05:29 AM - Re: Electrical grounding block (Sam Marlow)
     2. 06:17 AM - Re: Re: ELT Antenna Placement (Robert L. Nuckolls, III)
     3. 06:30 AM - Re: Electrical grounding block (Robert L. Nuckolls, III)
     4. 08:05 AM - Re: Grounding question (Robert L. Nuckolls, III)
     5. 12:04 PM - Re: Re: ELT Antenna Placement (Craig Payne)
     6. 01:40 PM - ELT Rubber Ducky Antenna? (bcondrey)
     7. 03:44 PM - Re: ELT Rubber Ducky Antenna? (Robert L. Nuckolls, III)
     8. 03:44 PM - Re: Electrical grounding block (LarryRobertHelming)
     9. 04:05 PM - Re: ELT Rubber Ducky Antenna? (Craig Payne)
 
 
 


Message 1


  • INDEX
  • Back to Main INDEX
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 05:29:33 AM PST US
    From: Sam Marlow <sam.marlow@adelphia.net>
    Subject: Re: Electrical grounding block
    --> AeroElectric-List message posted by: Sam Marlow <sam.marlow@adelphia.net> Thanks, good source! Do not archive. Bill Steer wrote: >--> AeroElectric-List message posted by: "Bill Steer" <steerr@bellsouth.net> > >B&C. Take a look at www.bandcspecialty.com. > >Bill > >Do not archive > > > > >>Anybody care to share whwer they purchased a grounding block? >> >> > > > > > > > > >


    Message 2


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 06:17:11 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: ELT Antenna Placement
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 12:00 PM 5/26/2006 -0600, you wrote: >--> AeroElectric-List message posted by: "Craig Payne" ><craig@craigandjean.com> > >The instructions for my new Artex ME406 406 MHz ELT have additional >requirements: > >"Locate the antenna at least 30 inches away from other antennas, wires, >vertical stabilizer, etc. to minimize distortion of the radiated field and >interference with other equipment. The antenna must be installed VERTICALLY >(within 15 of the vertical plane is acceptable). Artex has no performance >data for installations that deviate from the stated requirements." > >(http://www.artex.net/documents/570-1600Rev-1.pdf) > >This is almost impossible on my Zenith 601XL so I am doing the best I can. . . , which is all anyone can. Virtually every manufacturer cites their fondest wishes in the installation manual that virtually never work out in real life. Generally, effects of 'deviations' require laboratory grade instruments to detect and quantify . . . and most have no major contribution to the outcome of any given crash/recovery scenario. Don't loose any sleep over it. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > ---------------------------------------------------------


    Message 3


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 06:30:45 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Electrical grounding block
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 07:19 PM 5/26/2006 -0500, you wrote: >--> AeroElectric-List message posted by: "LarryRobertHelming" ><lhelming@sigecom.net> > >I bought mine from B&C electric. I bought one of each size. A small one >for the main buss, and large one for the ground, and the medium size for the >e-buss. I had to double up a few on the ground buss cause I ran every >ground back to the buss. Larry in Indiana Don't understand how you used these for "the main buss" and "e-bus" . . . I can't think of any rationale for having separate grounds dictated by which power bus they're associated with . . . Bob . . .


    Message 4


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 08:05:39 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Grounding question
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 05:12 PM 5/26/2006 +0200, you wrote: >--> AeroElectric-List message posted by: Mickey Coggins ><mick-matronics@rv8.ch> > > >> In my case in my RV Super 8 with my Batt in the back, I grounded it > >> locally & ran a 12ga to the front, from the battery, for grounding of > >> all the 'stuff' to a single point. I have a perfectly quiet electrical > >> system. For all practical purposes, only the starter & alternator, are > >> using the airframe ground. > >> Mike > > > > Not a good deal. That long ground isn't really a ground. Please > > consider using the single point ground block mounted on the firewall > > as depicted in the Connection and making all cockpit and forward > > accessory grounds at that point limiting your local airframe grounds > > to the list cited in my posting of last night. > >I'm confused. Why wouldn't Mike's 12ga wire extended to an >isolated forest of tabs be a ground? > >I considered doing the same, but decided to ground the >forest of tabs to the front of the aircraft as well. > >Here's how mine is set up: > >http://www.rv8.ch/article.php?story=20060301215616213 > >I added the "fat" ground wire between the front forest >of tabs to the batteries in the back mainly to carry >starter currents a bit more efficiently. I was afraid >that if I didn't, something between where I ground >the engine and the battery would get welded together >when I cranked the starter. > >BTW, the engine cranks fine, but I have no idea about >noise, since I don't yet have my radio installed. "Ground" systems are much more than multiple systems simply sharing a common conductor to satisfy their individual needs for conductivity. The dynamic nature of "ground" is dependent on its conductivity, geometry and discontinuities. The ideal vehicular "ground" conductor would probably be a welded joint, relatively thick sheet of highly conductive material . . . say copper or silver and have the minimum possible surface area to enclose a given volume . . . hence a sphere. Spheres and copper do not lend themselves well to the fabrication of vehicular structures so instead we find ourselves dealing with a variety of materials ranging from excellent insulators (epoxy/glass) to pretty good conductors (stir-welded aluminum) and all technologies in between. Further, they're not spherical. To make matters more interesting, the conduction pathways for systems that share "ground" in any vehicle are never straightest lines between two points on the system. Just to make matters still more interesting, the prudent designer has to consider the effectiveness and cross coupling of signals for frequencies ranging from DC to microwave. There's a condition in the RAC Hawker 800 series aircraft where an antenna system using airframe for part of the antenna's RF 'ground' excites spaces in the hell-hole to the tune of over 100 volts/meter at various HF frequencies when the transmitter is keyed. It varies from airplane to airplane and is not a "problem" for most airplanes. But the effects are present on every airplane and from time to time, rise up and halt delivery of a multi-million dollar machine because the ground system was not properly configured for this application. Worse yet, it would cost staggering amounts of money to fix it now. Instead, we craft individual Band-Aids on an airplane-by-airplane basis when a particular combination of circumstances rise to intolerable interference levels. This dissonant array of conditions that never approach the ideal ground system is NEVER a problem for any one system operating by itself . . . nor is it a problem for systems that are generally not vulnerable to ground induced coupling of noises from a potential antagonist to a potential victim system. This gives rise to many builder's assertions that their particular version of a ground system "works just fine" . . . and he's not wrong. Just as I've cited for the Hawkers above, there are ground system issues that while they are predictable and even measurable, the magnitude of the 'interference' is below the threshold of deleterious effects. This is why 99.9% of all airplanes crafted over the last 100 years are considered by their owners to be 'satisfactory' performers. Only the occasional machine comes to the attention of some poor avionics tech who now has to figure out how to work around a noise problem that would have best been designed out in the first place. Ladies and gentlemen, to offer a comprehensive course in ground system design features and effects of poor science is beyond the scope of activities we can offer in this venue. You folks need to concentrate on getting first-light-under-the-wheels with a minimum of $time$ and lowest practical cost of ownership later. Be wary of variations on a theme for ground system features that depart from those suggested in the 'Connection and in the considered words of the grey-beards on the List. Virtually every variation offered to you by some builder you met at a fly-in will be touted as a 'solution' to some unfounded concern or a desire to cut a corner . . . and since the airplane flew to that gathering, no doubt the owner will report "it works fine". The grounding philosophies offered in this venue are a prophylactic effort designed to avoid that 0.1%, pain-in-the-arse airplane that's going to be expensive in $time$ at some point in the future. These same philosophies also attenuate the 10-20% of the airplanes that have some degree of noise issue which the owner is willing to accept as below his personal threshold of deleterious performance. The double-grounding architecture described above is generally not a significant improvement in ground system performance and opens the doors for new issues. In another time, I'll tell you the saga of a "double ground" issue that rose up in a Beechjet a year or so ago that had a very expensive airplane down for months (at taxpayer expense) and took hundreds of hours to find and fix. "Extending" ground busses for major chunks of system hardware on the end of a 12AWG wire makes everything 'grounded' by that wire subject to single point failure of one wire. Further, the resistance/inductance contributed to the system by the wire length makes it less than ideal ground. These are 'experimental' airplanes and one can certainly do as he/she wishes in terms of personalizing the electrical system architecture. Most variations will be found to function in a 'satisfactory' manner. Just be aware that departures from architectures configured with use of well considered science and experience tosses out the $time$ invested in crafting those architectures. They also elevate the risk for added expense and aggravation at some later date. The fruits of those investments are being shared with you at virtually zero expense so as to minimize $time$ to first-light and $time$ needed to fix something later when you'd rather be flying. Bob . . .


    Message 5


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 12:04:00 PM PST US
    From: "Craig Payne" <craig@craigandjean.com>
    Subject: Re: ELT Antenna Placement
    --> AeroElectric-List message posted by: "Craig Payne" <craig@craigandjean.com> >> Don't loose any sleep over it. >> >> Bob . . . The other listed requirement is "do not crash" :-) -- Craig


    Message 6


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 01:40:06 PM PST US
    Subject: ELT Rubber Ducky Antenna?
    From: "bcondrey" <bob.condrey@baesystems.com>
    --> AeroElectric-List message posted by: "bcondrey" <bob.condrey@baesystems.com> Bob N., In the past you've cited the possibility using a rubber ducky style antenna for ELTs. Would this also be an option for the newer style 121.5/406 MHz types such as the Artex ME406? Thanks Bob Read this topic online here: http://forums.matronics.com/viewtopic.php?p=36874#36874


    Message 7


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 03:44:02 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: ELT Rubber Ducky Antenna?
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 01:35 PM 5/27/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "bcondrey" ><bob.condrey@baesystems.com> > >Bob N., > >In the past you've cited the possibility using a rubber ducky style >antenna for ELTs. Would this also be an option for the newer style >121.5/406 MHz types such as the Artex ME406? > >Thanks >Bob Only if the "rubber duck" has been crafted for dual frequency operations. The instance I suggested that the shortened antenna be considered was the case where a pair of antennas . . . a 121.5 and a 406 MHz device were mounted side by side under the fiberglas toe cover of the vertical fin fairing on a Beechjet: http://www.aeroelectric.com/temp/400A_ELT.jpg When the fairing cover was installed, metallic braces in the fairing upset the SWR on the longer, 121.5 MHz antenna and caused self-test failures. They considered the short antenna until we discovered that the ELT had been qualified under TSO with these specific antennas . . . we couldn't use a different antenna without re-qualifying. So . . . they widened the trip tolerance on the SWR self check . . . another case where under very un-helpful regulation, two wrongs made a "right." (sigh) Anywho, I suspect your more modern design is paired with an antenna designed for optimum performance at two frequencies and the simple rubber duck is not an option for you. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > ---------------------------------------------------------


    Message 8


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 03:44:02 PM PST US
    From: "LarryRobertHelming" <lhelming@sigecom.net>
    Subject: Re: Electrical grounding block
    --> AeroElectric-List message posted by: "LarryRobertHelming" <lhelming@sigecom.net> You have lost me somewhere Bob. I agree there is no need for separate ground busses. Your book sold me on the need for separate power busses. I was referring to all busses when I mentioned large, medium and small. The busses -- which ever purpose they are placed into duty for -- are all sold by B&C under the description of buss. There is no distinction of their use. There are different sizes and the grounding buss, which serves all power needs, requires the largest number of terminals. Thanks for calling this need for clarification to my attention. Larry in Indiana ----- Original Message ----- > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > <nuckollsr@cox.net> > > At 07:19 PM 5/26/2006 -0500, you wrote: > >>--> AeroElectric-List message posted by: "LarryRobertHelming" >><lhelming@sigecom.net> >> >>I bought mine from B&C electric. I bought one of each size. A small one >>for the main buss, and large one for the ground, and the medium size for >>the >>e-buss. I had to double up a few on the ground buss cause I ran every >>ground back to the buss. Larry in Indiana > > > Don't understand how you used these for "the main buss" and > "e-bus" . . . I can't think of any rationale for having separate > grounds dictated by which power bus they're associated with . . . > > > Bob . . . > > >


    Message 9


  • INDEX
  • Back to Main INDEX
  • PREVIOUS
  • Skip to PREVIOUS Message
  • NEXT
  • Skip to NEXT Message
  • LIST
  • Reply to LIST Regarding this Message
  • SENDER
  • Reply to SENDER Regarding this Message
    Time: 04:05:59 PM PST US
    From: "Craig Payne" <craig@craigandjean.com>
    Subject: ELT Rubber Ducky Antenna?
    --> AeroElectric-List message posted by: "Craig Payne" <craig@craigandjean.com> >> Anywho, I suspect your more modern design is paired with an antenna designed for optimum performance at two frequencies and the simple rubber duck is not an option for you. Bob . . . << The Artex 121.5/406.028 MHz ELTs can be bought bundled with antennas selected to support the dual frequencies. That's what I did. I'll tell you how it works after my next crash. -- Craig




    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
  • Full Archive Search Engine
  •   http://www.matronics.com/search
  • 7-Day List Browse
  •   http://www.matronics.com/browse/aeroelectric-list
  • Browse AeroElectric-List 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/contributions

    These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.

    -- Please support this service by making your Contribution today! --