---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 09/19/04: 26 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:10 AM - Re: RG Batt (Gilles Thesee) 2. 05:36 AM - Re: RG Batt (Brian Lloyd) 3. 06:44 AM - Re: Re: RG Batt (Brian Lloyd) 4. 06:58 AM - Re: Wire colors by function (Ed OConnor) 5. 08:01 AM - Matronics subscribe problems (Robert L. Nuckolls, III) 6. 08:05 AM - Charging () 7. 08:14 AM - Re: Wire colors by function (Robert L. Nuckolls, III) 8. 08:58 AM - Re: Matronics subscribe problems (Mickey Coggins) 9. 09:06 AM - Re: RG Batt (Gert) 10. 09:55 AM - Re: RG Batt (ALWAYSPDG@aol.com) 11. 10:28 AM - Need BNC installation instructions (Roger Evenson) 12. 10:41 AM - Re: Need BNC installation instructions (Richard E. Tasker) 13. 10:43 AM - Re: Need BNC installation instructions (Werner Schneider) 14. 12:36 PM - Re: RG Batt (Robert L. Nuckolls, III) 15. 01:00 PM - Aircraft Wiring for Smart People Reviewed (Robert L. Nuckolls, III) 16. 01:05 PM - Re: Need BNC installation instructions (Robert L. Nuckolls, III) 17. 02:42 PM - Re: Aircraft Wiring for Smart People Reviewed (Malcolm Thomson) 18. 02:58 PM - Re: Aircraft Wiring for Smart People Reviewed (Paul Messinger) 19. 03:18 PM - Re: Aircraft Wiring for Smart People Reviewed (Trampas) 20. 04:40 PM - Renamed- RF health concerns (Ken) 21. 05:36 PM - Re: Aircraft Wiring for Smart People (Robert L. Nuckolls, III) 22. 06:07 PM - Re: Aircraft Wiring for Smart People (Robert L. Nuckolls, III) 23. 06:22 PM - Re: COM antenna in a gear leg fairing? (SportAV8R@aol.com) 24. 06:23 PM - RF health concerns on juliet (Robert L. Nuckolls, III) 25. 06:25 PM - Re: Aircraft Wiring for Smart People Reviewed (Fiveonepw@aol.com) 26. 07:38 PM - My address is go doodoo (Fergus Kyle) ________________________________ Message 1 _____________________________________ Time: 12:10:01 AM PST US From: "Gilles Thesee" Subject: Re: AeroElectric-List: RG Batt --> AeroElectric-List message posted by: "Gilles Thesee" ----- Original Message ----- From: Subject: AeroElectric-List: RG Batt > --> AeroElectric-List message posted by: > > I just found that the RG battery in my Beech was discharged down to 5 volts since putting it the hangar 3 weeks ago. [ Gee! Wonder how that could have happened? Take pity and don't answer.] > > The problem now is that it does not want to take a charge. What is the proper way to re-charge a seriously depleted RG batt? > > Thanks for any advice. > Jim, Here is what I would do : - Search the manufacturer website for the recommended charging mode. In my case they say the preferred mode is constant voltage charging. - Use a good bench supply (laboratory supply from a school or else) and have a try at recharging. - If unsuccessful, consider buying a new RG battery. After all they are lead/acid batteries, and as such they don't like staying discharged for any length of time. Sorry for not being of more help, Regards, Gilles Thesee Grenoble, France ________________________________ Message 2 _____________________________________ Time: 05:36:22 AM PST US From: Brian Lloyd Subject: AeroElectric-List: Re: RG Batt --> AeroElectric-List message posted by: Brian Lloyd > On Sep 18, 2004, at 5:27 PM, wrote: > >> --> AeroElectric-List message posted by: >> >> I just found that the RG battery in my Beech was discharged down to 5 >> volts since putting it the hangar 3 weeks ago. [ Gee! Wonder how that >> could have happened? Take pity and don't answer.] >> >> The problem now is that it does not want to take a charge. What is the >> proper way to re-charge a seriously depleted RG batt? > > Constant current charge at about a 1A rate. That will force the > battery to accept a charge if it can. > You have to be careful to monitor the battery's voltage though. It > will start out very high since the discharged cells are in a > high-resistance state. As they start to take a charge the voltage > will drop to 13-14 volt range. Once that happens you can switch to a > constant-voltage charge at about 14.2 volts. The battery is charged > when the charging current drops to 5% of the battery's amp-hour > rating, i.e. a 30AH battery is charged when the charging current drops > to 3A when charged at the proper charge voltage. Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 +1.340.998.9447 St. Thomas, VI 00802 ________________________________ Message 3 _____________________________________ Time: 06:44:14 AM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Re: RG Batt --> AeroElectric-List message posted by: Brian Lloyd On Sep 19, 2004, at 8:35 AM, Brian Lloyd wrote: >> You have to be careful to monitor the battery's voltage though. It >> will start out very high since the discharged cells are in a >> high-resistance state. As they start to take a charge the voltage >> will drop to 13-14 volt range. Once that happens you can switch to a >> constant-voltage charge at about 14.2 volts. The battery is charged >> when the charging current drops to 5% of the battery's amp-hour >> rating, i.e. a 30AH battery is charged when the charging current drops >> to 3A when charged at the proper charge voltage. Let me try to get the math right this time. 5% of 30 is 1.5, not 3. So the battery is charged when the charge current drops to 1.5A when charging at the proper constant voltage. BTW, the proper charge voltage for an AGM battery is about 14.4V at 70F-80F. Proper charge voltage for a Gel-Cell is about 13.8V at the same temperature. You can leave the battery on a constant current charge but you should be careful to manage the time properly. Surprisingly lead-acid batteries are quite efficient in terms of storing electrons. They have a coulombic efficiency on the order of 90%-95%. That means if you pull X number of coulombs out of the battery (one amp is one coulomb per second) you only need to put X/95% coulombs back. Therefore if the battery is completely dead and it has a capacity of 30AH, you need to put 30/95% or 31.5 AH back. If you charge at a 1A rate it will take 31.5 hours to fully charge the dead battery. So while it is true that most manufacturers recommend constant voltage charging for their batteries, constant current charging is a better remedy for a dead battery. Just be careful not to let the battery overcharge, especially a sealed battery. That is my reason for recommending the low charge rate of 1A. Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 +1.340.998.9447 St. Thomas, VI 00802 ________________________________ Message 4 _____________________________________ Time: 06:58:20 AM PST US From: Ed OConnor Subject: Re: AeroElectric-List: Wire colors by function --> AeroElectric-List message posted by: Ed OConnor I read and article on web site about wiring up an aircraft. You can download this article. If you are just starting to wire up an aircraft, I would recommend it highly. He recommends Teflon wire vice the tfizil we are all using as it is easier to work with and has better specs. As for color coding, he highly recommends it as well as making twisted pair wires yourself with a drill and a common ground site.. There is a convention on the wiring color. The higher the voltage, the brighter the color I think. Its in the article. Its a beta version of the final article but informative I think. ________________________________ Message 5 _____________________________________ Time: 08:01:58 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Matronics subscribe problems --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >Saturday, September 18, 2004 > >John Esch > >, >Email: jfesch@earthlink.net >Comments/Questions: Bob >I am having troubles trying to subscribe to the Aeroelectric Digest. I >believe it might be in my security settings. >Could I be added to the above named digest? > >Thanks in advance > >John Esch >jfesch@earthlink.net When you filled in your e-mail address, and subscribed to any of the list server forums, did you get a confirmation e-mail? Nobody can do the subscribe/un-subscribe for you. It has to be done from your computer's i.p. address If your e-mail service has any kind of filter on it, it may be erroneously filtering mail originating from matronics.com There are a number of well-intentioned folks offering varieties of filters and 'net-accessible "black-lists" to assist in spam reduction. It's entirely possible that legitimate mass mailers like matronics could be added to a black-list relied on by your spam filter. I only use a spam filter called "Mailwasher". While it's not as convenient as those supplied by Internet services providers, at least it runs in my computer and allows me to set up my own black-list. Further, it doesn't automatically drop any e-mails in the trash. I see a line-item listing for every incoming mail item. Most of what I get is marked for deletion when the return address matches either my personally maintained black-list or one of several 'net-based lists. If a message originating from matronics shows up as black-listed, I can manually accept it and let Matt Dralle know that his services have been erroneously added to somebody's black-list on the 'net. If normal subscribing techniques are not working for you, and after you've considered all of the options for errors by spam filters, contact Matt Dralle directly at Matronics and see what he recommends. Bob . . . Bob . . . ----------------------------------------- ( Experience and common sense cannot be ) ( replaced with policy and procedures. ) ( R. L. Nuckolls III ) ----------------------------------------- ________________________________ Message 6 _____________________________________ Time: 08:05:51 AM PST US From: Subject: AeroElectric-List: Charging --> AeroElectric-List message posted by: Thanks for all the responses to my charging question. Jim ________________________________ Message 7 _____________________________________ Time: 08:14:21 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Wire colors by function --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:57 AM 9/19/2004 -0500, you wrote: >--> AeroElectric-List message posted by: Ed OConnor > >I read and article on web site about wiring >up an aircraft. You can download this article. If you are just >starting to wire up an aircraft, I would recommend it highly. He >recommends Teflon wire vice the tfizil we are all using as it is easier >to work with and has better specs. As for color coding, he highly >recommends it as well as making twisted pair wires yourself with a >drill and a common ground site.. There is a convention on the wiring >color. The higher the voltage, the brighter the color I think. Its in >the article. Its a beta version of the final article but informative I >think. I've been getting a bunch of private e-mails about this article over and above the little bit of traffic here on the list. I've read the article in detail . . . and in fact downloaded the original Word version. I spent about 6 hours Friday doing a paragraph-by-paragraph review and I'm about half done. I'll be publishing the review in its entirety late today or perhaps tomorrow. It's loaded with gross errors and utterly devoid of simple-idea foundation for recommendations. I simply couldn't allow this effort bubble up to the surface in the great sea of information without being challenged. In a nutshell the article is "all foam and no beer". You heard it first here on the AeroElectric List. Home for motivated students, good teachers and fabricators of the finest aircraft to have ever flown. Bob . . . --- ________________________________ Message 8 _____________________________________ Time: 08:58:06 AM PST US From: Mickey Coggins Subject: Re: AeroElectric-List: Matronics subscribe problems --> AeroElectric-List message posted by: Mickey Coggins Hi John, Many Earthlink customers have set up spam filters, and you need to manually add the E-mail address owner-aeroelectric-list-server@matronics.com to your "good guy" list. Not sure what it is called at Earthlink. Mickey At 17:11 19-09-04, Robert L. Nuckolls, III wrote: -----Start of Original Message----- >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > >>Saturday, September 18, 2004 >> >>John Esch >> >>, >>Email: jfesch@earthlink.net >>Comments/Questions: Bob >>I am having troubles trying to subscribe to the Aeroelectric Digest. I >>believe it might be in my security settings. >>Could I be added to the above named digest? >> >>Thanks in advance >> >>John Esch >>jfesch@earthlink.net > > > When you filled in your e-mail address, and subscribed to > any of the list server forums, did you get a confirmation > e-mail? Nobody can do the subscribe/un-subscribe for you. > It has to be done from your computer's i.p. address > > If your e-mail service has any kind of filter on it, > it may be erroneously filtering mail originating > from matronics.com > > There are a number of well-intentioned folks offering > varieties of filters and 'net-accessible "black-lists" to > assist in spam reduction. It's entirely possible that > legitimate mass mailers like matronics could be added > to a black-list relied on by your spam filter. > > I only use a spam filter called "Mailwasher". While > it's not as convenient as those supplied by Internet > services providers, at least it runs in my computer > and allows me to set up my own black-list. Further, > it doesn't automatically drop any e-mails in the trash. > I see a line-item listing for every incoming mail item. > Most of what I get is marked for deletion when the > return address matches either my personally maintained > black-list or one of several 'net-based lists. If a > message originating from matronics shows up as black-listed, > I can manually accept it and let Matt Dralle know that > his services have been erroneously added to somebody's > black-list on the 'net. > > If normal subscribing techniques are not working for > you, and after you've considered all of the options for > errors by spam filters, contact Matt Dralle directly at Matronics > and see what he recommends. > > Bob . . . -- Mickey Coggins http://www.rv8.ch/ #82007 QB Wings/Fuselage ________________________________ Message 9 _____________________________________ Time: 09:06:34 AM PST US From: Gert Subject: Re: AeroElectric-List: RG Batt --> AeroElectric-List message posted by: Gert What about the batteryminder which claims to be able to desulfate batteries as well, such as :http://www.batteryweb.com/batteryminder.cfm I saw ACS now selling these desulfating critters........ Gert ALWAYSPDG@aol.com wrote: > --> AeroElectric-List message posted by: ALWAYSPDG@aol.com > > I would try the "Battery Tender". It has worked for me in the past. It > charges at a very low amperage and is fully automatic. Here is the website for > more info. > > _http://www.batterytender.com/_ (http://www.batterytender.com/) > > Mike > > > > > > -- is subject to a download and archival fee in the amount of $500 ________________________________ Message 10 ____________________________________ Time: 09:55:33 AM PST US From: ALWAYSPDG@aol.com Subject: Re: AeroElectric-List: RG Batt --> AeroElectric-List message posted by: ALWAYSPDG@aol.com I don't have any experience with the battery minder but, after reading the information on it, it sounds like it would work too. I have used the Battery Tender over many years and it works great. I have used it on Jet Skis, automotive, motorcycle, and of course airplanes. Mike ________________________________ Message 11 ____________________________________ Time: 10:28:22 AM PST US From: "Roger Evenson" Subject: AeroElectric-List: Need BNC installation instructions --> AeroElectric-List message posted by: "Roger Evenson" I've purchased a couple of BNC connectors from B&C for RG400 (crimp style or maybe crimp and solder style), but can't find installation instructions. I searched the archives and found these, but they are no longer available. http://216.55.140.222/articles/BNC_Install/BNC_Install1.jpg http://216.55.140.222/articles/BNC_Install/BNC_Install2.jpg Bob . . . Anybody find any instructions on preparing the cable ends and crimping the connectors? Roger E. ________________________________ Message 12 ____________________________________ Time: 10:41:00 AM PST US From: "Richard E. Tasker" Subject: Re: AeroElectric-List: Need BNC installation instructions --> AeroElectric-List message posted by: "Richard E. Tasker" Just change the "216.55.140.222" to "www.aeroelectric.com" and you will find them. Since Bob moved the website a while back, the old number URL is no longer correct. Substitute "www.aeroelectric.com" for all your old addresses and they will almost always work. Dick Tasker Roger Evenson wrote: >--> AeroElectric-List message posted by: "Roger Evenson" > >I've purchased a couple of BNC connectors from B&C for RG400 (crimp style or maybe crimp and solder style), but can't find installation instructions. I searched the archives and found these, but they are no longer available. > >http://216.55.140.222/articles/BNC_Install/BNC_Install1.jpg >http://216.55.140.222/articles/BNC_Install/BNC_Install2.jpg > > Bob . . . > >Anybody find any instructions on preparing the cable ends and crimping the connectors? > >Roger E. > > ________________________________ Message 13 ____________________________________ Time: 10:43:11 AM PST US From: "Werner Schneider" Subject: Re: AeroElectric-List: Need BNC installation instructions --> AeroElectric-List message posted by: "Werner Schneider" Hello Roger, you get caught by a link when Bob's server was done and he had to put up an interim server, replace 216.55.140.22 with www.aeroelectric.com and you will see it. Also to recommend: http://www.aeroelectric.com/articles/bnccrimp.pdf most probably the one you need. http://www.aeroelectric.com/articles/coaxconn/coaxconn.html Werner ----- Original Message ----- From: "Roger Evenson" Subject: AeroElectric-List: Need BNC installation instructions > --> AeroElectric-List message posted by: "Roger Evenson" > > I've purchased a couple of BNC connectors from B&C for RG400 (crimp style or maybe crimp and solder style), but can't find installation instructions. I searched the archives and found these, but they are no longer available. > > http://216.55.140.222/articles/BNC_Install/BNC_Install1.jpg > http://216.55.140.222/articles/BNC_Install/BNC_Install2.jpg > > Bob . . . > > Anybody find any instructions on preparing the cable ends and crimping the connectors? > > Roger E. > > ________________________________ Message 14 ____________________________________ Time: 12:36:17 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RG Batt --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:27 PM 9/18/2004 -0400, you wrote: >--> AeroElectric-List message posted by: > >I just found that the RG battery in my Beech was discharged down to 5 >volts since putting it the hangar 3 weeks ago. [ Gee! Wonder how that >could have happened? Take pity and don't answer.] > >The problem now is that it does not want to take a charge. What is the >proper way to re-charge a seriously depleted RG batt? > >Thanks for any advice. Batteries that are completely discharged (below 10/20 volts) and stored in this condition for any length of time may not be recoverable. If it does not accept a charge with the ordinary voltage regulated charger, you MIGHT be able to force-feed it with a higher voltage from a power supply. My friends at Concord have related stories of successful recoveries (in fact, there's a requirement for demonstrating recovery of certain military program batteries after being stored with a 5 ohm shorting resistor for 30 days). The recovery technique is to 'stuff' a charge back into it using 16-20 volts or as required to get C/10 charge current to flow (24 a.h. battery needs to see at least 2.5 amps). Hold this as a constant current charge for 12 hours. Discharge the battery at C/1 rate (24 amps for a 24 a.h. battery) until it falls to 10 volts. Recharge at C/10 but voltage limit this time to 14.2 volts. Discharge at C/1 rate and measure capacity. If less than 80% of nameplate value, repeat the recharge/discharge cycle several times. If the capacity does not increase each cycle (or if you can't get to 80% of nameplace capacity, the battery is shot. There are a number of batteries offered to the military which survived this test when relatively new. The older the battery is (and the longer it sits in a discharged state) the less likely it is that you wlll get it back. If you have power in your hangar, I'll suggest you put a "Battery Tender" on while the airplane is stored. Also check to make sure you don't have always-on battery bus loads that are causing the battery to discharge while the airplane is stored. A substantial cause of battery replacement on biz jets is the baggage compartment or commode drain service lights that are left on. See http://batterytender.com/product_info.php?products_id=4 I have a half dozen RG instrumentation batteries in my shop that are floated on Battery Tenders. They're always 100% and ready to go even if I've not touched them in months. Bob . . . --- ________________________________ Message 15 ____________________________________ Time: 01:00:36 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" I've spent as much time on this "booklet" as I can. I've already spotted a bunch of spelling and syntax errors to fix but I think the meat of the review is essentially complete. I'm not going to link the review to my website's Front and What's New pages until I've had time to fix all the problems I can find. In the mean time, AeroElectric List members are welcome to check out this work in progress at: http://www.aeroelectric.com/articles/Aircraft_Wiring_For_Smart_People_Reviewed.pdf Bob . . . --- ________________________________ Message 16 ____________________________________ Time: 01:05:20 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Need BNC installation instructions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:27 AM 9/19/2004 -0700, you wrote: >--> AeroElectric-List message posted by: "Roger Evenson" > > >I've purchased a couple of BNC connectors from B&C for RG400 (crimp style >or maybe crimp and solder style), but can't find installation >instructions. I searched the archives and found these, but they are no >longer available. > >http://216.55.140.222/articles/BNC_Install/BNC_Install1.jpg >http://216.55.140.222/articles/BNC_Install/BNC_Install2.jpg > > Bob . . . Several years ago, I was out of room and connectivity for storing all website's downloadables on one server. I had a library server located at 216.55.140.222 where overflow was billeted. All those documents were moved back to the core server for aeroelectric.com when we got the new server up and running a couple of years ago out in SanDiego. That server too small once more so we've bought a new killer byte thrasher with a bucket full of hard drives and dual processors. We should have that on line in the next 30 days or so. Just be aware that any links calling out the 216.55.140.222 address were temporary and are now accessed by replacing the string of IP address numbers with aeroelectric.com Bob . . . --- ________________________________ Message 17 ____________________________________ Time: 02:42:32 PM PST US From: "Malcolm Thomson" Subject: RE: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Malcolm Thomson" A question I have from the 24V vs. 12V discussion in the booklet is the assumption is made that the aircraft systems operate at 24V continuously. If, in a 24V system, smaller wire is used to reduce wire size, what happens when the alternator(s) fails and the battery voltage starts to drop? Most modern avionic systems operate from 10-32V, so therefore won't the radio which used, say 3A at 28V, need 6A at 12V? Does this mean it will need the same wire size as if it had been wired for a 12V system? Perhaps I'm missing something here. Thanks ----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" --> I've spent as much time on this "booklet" as I can. I've already spotted a bunch of spelling and syntax errors to fix but I think the meat of the review is essentially complete. I'm not going to link the review to my website's Front and What's New pages until I've had time to fix all the problems I can find. In the mean time, AeroElectric List members are welcome to check out this work in progress at: http://www.aeroelectric.com/articles/Aircraft_Wiring_For_Smart_People_Re viewed.pdf Bob . . . --- == direct advertising on the Matronics Forums. == == == ________________________________ Message 18 ____________________________________ Time: 02:58:26 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Paul Messinger" Bob there are rules and regs regarding the human proximity to RF sources IE antennas. Every Ham radio operator is required to evaluate his antenna installation to see if it meets these rules. In Europe I understand the rules (permissible levels) are much stricter. I do not have the specific FAA document # nor a copy handy but I suspect that a couple hundred (1000mhz) watts, even as pulses, a couple feet from you is a no no. This without a proper ground plane that would prevent back side radiation. Worth looking into in any event for those inclined to worry. I suspect less exposure if the antenna is directly under you presuming the above ground plane VS a small ground plane (only) and some distance from you. Interesting set of comments worth reading by everyone. You found some "errors" that I had missed. Good Job. Paul K6QMI Copyright @ 2004 by Greg Richter greg@bluemountainavionics.com Page 25 of 59 Safety Note About Transponder Antennas A transponder puts out a couple hundred Watt microwave pulse in a frequency band that is none too healthy to be around. On a metal airplane this is no big deal, since the whole thing is one big, shielded can. On a composite bird, you can be sitting unpleasantly close to a powerful microwave transmitter, which is Not Good. Mount the antenna as far away as practical, or failing that, use SuperShield to shoot a ground plane between you and the antenna. One of my friend's airplanes actually has the antenna right under the pilot's seat! This is hangar-legend with no foundation in physics or physiology. Somebody launched this back in Burt's heyday with the Ez crowd and it's been jumping up from time to time ever since. ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Aircraft Wiring for Smart People Reviewed > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > I've spent as much time on this "booklet" as I can. ________________________________ Message 19 ____________________________________ Time: 03:18:44 PM PST US From: "Trampas" Subject: RE: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Trampas" Bob, I would like to thank you for doing a full review of the document! Your effort and knowledge is very much appreciated. I would also like to thank Greg for taking the time to write the initial article; after all if no one brings up the subject it is hard to learn. Regards, Trampas www.sterntech.com -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" I've spent as much time on this "booklet" as I can. I've already spotted a bunch of spelling and syntax errors to fix but I think the meat of the review is essentially complete. I'm not going to link the review to my website's Front and What's New pages until I've had time to fix all the problems I can find. In the mean time, AeroElectric List members are welcome to check out this work in progress at: http://www.aeroelectric.com/articles/Aircraft_Wiring_For_Smart_People_Review ed.pdf Bob . . . --- ________________________________ Message 20 ____________________________________ Time: 04:40:10 PM PST US From: Ken Subject: AeroElectric-List: Renamed- RF health concerns on juliet --> AeroElectric-List message posted by: Ken What about VHF antennas? I understand that an occasional 7 watts of VHF is probably relatively benign compared to repetitive hundred watt microwave pulses but is there any health concern with putting a VHF comm antenna above my head on an aluminum fuselage surrounded by 4 skylights? There is enough aluminum to act as 4 wide radial ground plane elements so I'm guessing that will that keep most of the RF away from my head but I've never really understood this black magic RF stuff... Unless someone knows more than me I guess I'll mount the antenna about 6 or so feet farther aft but hate to run the coax that far if there is no reason for it and it would still have a line of sight through the skylights to my noggin anyway. I could also mount if at the wing root of my high wing aircraft but that is still line of sight to my noggin. Ken Paul Messinger wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >Bob there are rules and regs regarding the human proximity to RF sources IE >antennas. Every Ham radio operator is required to evaluate his antenna >installation to see if it meets these rules. In Europe I understand the >rules (permissible levels) are much stricter. > >I do not have the specific FAA document # nor a copy handy but I suspect >that a couple hundred (1000mhz) watts, even as pulses, a couple feet from >you is a no no. This without a proper ground plane that would prevent back >side radiation. > >Worth looking into in any event for those inclined to worry. I suspect less >exposure if the antenna is directly under you presuming the above ground >plane VS a small ground plane (only) and some distance from you. > >Interesting set of comments worth reading by everyone. You found some >"errors" that I had missed. > >Good Job. > >Paul >K6QMI > > > ________________________________ Message 21 ____________________________________ Time: 05:36:23 PM PST US From: "Robert L. Nuckolls, III" Reviewed Subject: Re: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" Reviewed At 02:58 PM 9/19/2004 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >Bob there are rules and regs regarding the human proximity to RF sources IE >antennas. Every Ham radio operator is required to evaluate his antenna >installation to see if it meets these rules. In Europe I understand the >rules (permissible levels) are much stricter. > >I do not have the specific FAA document # nor a copy handy but I suspect >that a couple hundred (1000mhz) watts, even as pulses, a couple feet from >you is a no no. This without a proper ground plane that would prevent back >side radiation. > >Worth looking into in any event for those inclined to worry. I suspect less >exposure if the antenna is directly under you presuming the above ground >plane VS a small ground plane (only) and some distance from you. > >Interesting set of comments worth reading by everyone. You found some >"errors" that I had missed. > >Good Job. > >Paul >K6QMI Thank you. Yeah, there's been "rules" about proximity to RF emitters for decades. I worked the flight line at Boeing in my first real job out of high school. The B52's nose mounted mapping radar was a 50KW peak output device that would blow the receiver mixers out of airplanes facing them across the ramp. The average power output was something on the order of 50W total . . . if held your hand out in the beam you could just detect a warming of your hand. At his same time, another piece of equipment was pretty common to doctor's offices called a diathermy machine. Push-pull, 100THs running anywhere between 100 and 600 watts output at 27 mHz. The doc could couple this to your bod with a variety of capacitive and inductive coupling pads and select a power transfer anywhere between very rare to medium-well. These were in use for deep heat therapy for decades. I got a series of treatments on the doc's "cooker" while wrestling with a series of kidney infections as a kid. Did a batch of mini-sausages in the microwave this morning . . Dee likes 'em crispy. Takes about 7 minutes with 600 watts continuous being pumped into the oven cavity. We know that anything moist will warm up in the presence of RF energy exposure. There are variable effects depending on mass of the area exposed (the tiny cat whisker's in receiver mixer crystals couldn't withstand 1 microsecond pulses at 1000 pulses per second, but the bare hand could just feel the heat. Of course, frequency has an influence too. I'm not trying to minimize risks around RF . . . I've had coaxes open up and turn my shack into a real attention getting environment. I have a 50 year old scar on my right index finger from an RF burn off the metal edge around the linoleum topped desk that supported my equipment . . . and that was only a 180 watt transmitter! But let's consider the average transponder. 100-200 watt peaks in a stream of perhaps 50-100, 1 microsecond pulses every time the reply light comes on. So, 200W x 100 pulse/reply x 0.000001 sec/pulse yields 20 milliwatt-seconds per reply. The most vulnerable organs in the body are the eyes and they're a long way from the antenna and shadowed by your bod. Anecdotal stories of RF burns, blowing receivers out from across the ramp and crisping up my sausages can certainly give rise to ugly images of risk. But after you study the numbers, I'm quite comfortable making the assertion that a transponder antenna on a ground plane right under the pilot's seat of a LongEz represents no hazard to the family jewels. Now, if my supervisor had seen me stick my hand out there in front of the antenna, the rules would probably have required him to terminate me on the spot. Rules have all appearances of good intention but in fact, they tend to relieve rule-writers from having to be teachers and rule-followers from having to understand real risks. I prefer to understand. Bob . . . --- ________________________________ Message 22 ____________________________________ Time: 06:07:59 PM PST US From: "Robert L. Nuckolls, III" Reviewed Subject: RE: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" Reviewed At 03:41 PM 9/19/2004 -0600, you wrote: >--> AeroElectric-List message posted by: "Malcolm Thomson" > > >A question I have from the 24V vs. 12V discussion in the booklet is the >assumption is made that the aircraft systems operate at 24V >continuously. If, in a 24V system, smaller wire is used to reduce wire >size, what happens when the alternator(s) fails and the battery voltage >starts to drop? Most modern avionic systems operate from 10-32V, so >therefore won't the radio which used, say 3A at 28V, need 6A at 12V? >Does this mean it will need the same wire size as if it had been wired >for a 12V system? Perhaps I'm missing something here. Great question. Yes, radios and other accessories with switchmode power supplies are CONSTANT POWER INPUT loads. So, if the is set up in a 28 volt system and needs 2 amps to operate, it will draw 2.24 amps when the alternator quits and bus falls to 25v. At end of battery life (22v) the radio will draw 2.5 amps. The battery will pass 10 volts on its way toward zero whereupon the radio will be demanding 5.6 amps. This raises an excellent question as to operating duration under battery only ops from a 24 volt battery. It seems that the 10-32v equipment is going to be useful for an extended period of time compared to the "old style" accessory guaranteed down to only 22v low normal and 18v emergency. Consider an e-bus load and battery capacity sized for say, 3 hours battery only operation assuming constant current or constant resistance operation down to 22 volts. The 25 to 22 volts discharge segment represents 3 x 60 or 180 minutes of operation and uses more than 95% of the battery's total capacity. The MOST time we can expect a 10v operating device with constant current or constant resistance operation is 0.05 x 240 or another 12 minutes. Now, if the e-bus powers 10-32v, constant power devices battery depletion is hastened. 12 minutes of operation after the "old" stuff dies is wishful thinking. Besides, if we haven't put the airplane comfortably on the ground in the first 180 minutes, I'll suggest that the last 12 minutes isn't going to make the difference between a good day and a bad day in the cockpit. Now, should this drive decisions to increase wire size? I don't think so. If we've designed, maintained, and operated the system comfortably within the bounds of what's considered normal operating voltages, there's not enough variability in operating current do drive any decisions to up-size wire or fuses. Assume 22v operating currents in your original design decisions and you're covered. Bob . . . --- ________________________________ Message 23 ____________________________________ Time: 06:22:12 PM PST US From: SportAV8R@aol.com Subject: Re: AeroElectric-List: COM antenna in a gear leg fairing? --> AeroElectric-List message posted by: SportAV8R@aol.com I don't think the Archer antenna will fit a narrow chord structure like the leg fairing, but I may be wrong. I have some recent experiance I was going to post on the subject of these antennas, and your question gives a good segue... I spent the weekend with an RV wingtip, a roll of copper foil tape, and my MFJ antenna analyzer attempting to duplicate a flat, 2-D mversion of the 3-D tubing-framed antenna that is presently in my wingtip, built using dimensions in the 'Connection for the Archer-style gamma-fed monopole. The current wingtip antenna works fairly well but exhibits some shielding from the wing and has at one time shed a piece from vibration-induced failure of a soldder joint. I wanted to alter the design so that there was no risk of stuff falling off,and so the radiating element would be as close to the belly of the wingtip enclosure as possible, to reduce shading by the wing. Duplicating the antenna looked to be a straightforward excercise, given my prior experience and the availability of the MFJ amalyzer, without which one would need the patience of Job to get things dialed in. Initially, however, I experienced a huge amount of frustration trying to get resonance where I wanted it, and even after trimming and adjusting all sorts of dimensions and variable matching capacitance, I had an antenna with the right approximate shape, dimensions off somewhat from the shop notes, and a 3:1 VSWR bandwidth of much less than the aircraft comm band. Finally it dawned on me that the base of the antenna, specified in 'Connection figure 13-12 as "convenient length," was dfesigned to be attatched to the metal wing rib as a sort of ground-plane. I had started with about 24 inches of copper foil along the inner edge of the wingtip as a base, and when I lengthened this by another 6 inches, things began to "cook" on the test bench in a gratifying way. I ended up with an antenna that shows a VSWR of 1.8:1 at 118 MHz and 1.7:1 at 136 MHz. Resonance is near 125 MHz, and unity SWR is easily achieved by tweaking the variable capacitor which I substituted for the sandwich of aluminum and bakelite called out in the drawing. These results are obtained OFF the airplane, and will await further confirmation when test flights allow (I need a few coax fittings from B&C to finish lashing it up to the feedline and do further testing...) I will be glad to post final dimensional and electrical measurements for anyone interested in the application once I get it wrung out. Meanwhile I'm still flying with the brass tubing version in the wingtip, and I've even started eyeing the nosegear leg on the RV, wondering if that sucker can be shunt-fed with a J-pole type of parallel matching stub to achieve some nearly-vertical polarization. Concealed antennas are fun, but, in a metal airplane, definitely involve a lot of work and offer somewhat compromised performance. The quest continues... -Bill B ________________________________ Message 24 ____________________________________ Time: 06:23:12 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: RF health concerns on juliet --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:43 PM 9/19/2004 -0400, you wrote: >--> AeroElectric-List message posted by: Ken > >What about VHF antennas? >I understand that an occasional 7 watts of VHF is probably relatively >benign compared to repetitive hundred watt microwave pulses but is there >any health concern with putting a VHF comm antenna above my head on an >aluminum fuselage surrounded by 4 skylights? There is enough aluminum to >act as 4 wide radial ground plane elements so I'm guessing that will >that keep most of the RF away from my head but I've never really >understood this black magic RF stuff... > >Unless someone knows more than me I guess I'll mount the antenna about 6 >or so feet farther aft but hate to run the coax that far if there is no >reason for it and it would still have a line of sight through the >skylights to my noggin anyway. I could also mount if at the wing root of >my high wing aircraft but that is still line of sight to my noggin. Given that you transmit for seconds out of every flight hour and the transmitter is ONLY 7 watts at 120 Mhz, I wouldn't worry about it. Folks in public safety (police, fire departments, etc) run 2-5 watt walkie-talkies right against their face for a ton more exposure than you're going to get from the comm transmitter in your airplane. I don't know any firemen who have gone blind 'cause they talked too much on their radios. Bob . . . --- ________________________________ Message 25 ____________________________________ Time: 06:25:02 PM PST US From: Fiveonepw@aol.com Subject: Re: AeroElectric-List: Aircraft Wiring for Smart People Reviewed --> AeroElectric-List message posted by: Fiveonepw@aol.com This is very interesting, but if the device is fed via a 5 amp fuse, assuming proper design, would not that fuse be toast before the wire insulation, making voltage at a given time a bit moot? Circuit protection is CONDUCTOR protection, no? Mark From The PossumWorks In a message dated 09/19/2004 7:08:36 PM Central Standard Time, b.nuckolls@cox.net writes: Great question. Yes, radios and other accessories with switchmode power supplies are CONSTANT POWER INPUT loads. So, if the is set up in a 28 volt system and needs 2 amps to operate, it will draw 2.24 amps when the alternator quits and bus falls to 25v. At end of battery life (22v) the radio will draw 2.5 amps. The battery will pass 10 volts on its way toward zero whereupon the radio will be demanding 5.6 amps. ________________________________ Message 26 ____________________________________ Time: 07:38:10 PM PST US From: "Fergus Kyle" Subject: AeroElectric-List: My address is go doodoo --> AeroElectric-List message posted by: "Fergus Kyle" The manager of my server has had a spam-finder program go wrong and as a result has shut down temporarily to repair same. Please forgive any false warning of my immediate demise. I expect to be back, receiving messages as always. Thank you, and apologies, Ferg Europa A064