---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 07/24/07: 17 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:32 AM - Solar Charger (Chris Byrne) 2. 04:07 AM - Re: ELT Question (Robert Feldtman) 3. 08:57 AM - Re: DIY - In the ear headphones (Bill Boyd) 4. 09:39 AM - Re: DIY - In the ear headphones (John Burnaby) 5. 11:27 AM - Re: DIY - In the ear headphones (Ernest Christley) 6. 02:13 PM - Re: DIY - In the ear headphones (Rob Housman) 7. 02:46 PM - Re: Double-shielded coax (Robert L. Nuckolls, III) 8. 02:47 PM - Re: Avionics master switch/relay (Robert L. Nuckolls, III) 9. 02:56 PM - Re: http://smartaircraftsystems.com/ (Robert L. Nuckolls, III) 10. 03:08 PM - Re: Semi-Custom Products (Robert L. Nuckolls, III) 11. 03:46 PM - Re: DIY - In the ear headphones (Ernest Christley) 12. 04:23 PM - Re: Solar Charger (Karl Ahamer) 13. 05:16 PM - Re: DIY - In the ear headphones (Charlie England) 14. 05:27 PM - Re: DIY - In the ear headphones (Rob Housman) 15. 05:48 PM - Re: DIY - In the ear headphones (Charlie England) 16. 07:29 PM - Re: DIY - In the ear headphones (Ernest Christley) 17. 09:13 PM - Off to OSH (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 02:32:41 AM PST US From: "Chris Byrne" Subject: AeroElectric-List: Solar Charger I am wanting to purchase a solar powered charger that is compatible with an ODESSY battery. This will be used as a trickle charger/battery maintainer. By the way can you get a solar charger that will give a full charge and revert to trickle? Regards Chris Byrne SYDNEY ________________________________ Message 2 _____________________________________ Time: 04:07:02 AM PST US From: "Robert Feldtman" Subject: Re: AeroElectric-List: ELT Question it will work fine. RG400 is expensive, but nice, RG58 will do just fine. bobf W5RF On 7/23/07, Greg Vouga wrote: > > > > > All, > > I'm installing a standard Ameri-King AK-450 ELT in my RV-7A to satisfy the > FAA. I have a question about the coax wire connection. I need a couple > extra feet of cable for my installation. I'm putting the antenna under > the > tail fairing and the ELT behind the baggage wall. Is it a good idea to > use > RG-400 to make a longer cable? Asside from the obvious "because > Ameri-King > says not to," is there a reason why this won't work? Maybe it would be > necessary to tune the new cable/antenna combination? If so, do I need > special equipment? > > Thanks, > Greg > > _________________________________________________________________ > Need a brain boost? Recharge with a stimulating game. Play now! > http://club.live.com/home.aspx?icid=club_hotmailtextlink1 > > ________________________________ Message 3 _____________________________________ Time: 08:57:04 AM PST US From: "Bill Boyd" Subject: Re: AeroElectric-List: DIY - In the ear headphones Keep us posted! Bill B ...satisfied Lightspeed Mach one user but out $400... On 7/23/07, Ernest Christley wrote: > > echristley@nc.rr.com> > > I've been looking into building a in-the-ear type headset using low-end > earphones, following the example given at > > http://www.canardzone.com/members/nickugolini/CuplessHeadet/cupless_headset.htm > > > I bought the Phillips ANR headphones from Target. I've got Jim Weir's > impedance matching circuit article describing how to use the audio > transformer, so the headphone portion is in the bag. > > The hangup is with the microphone. I found some discussions where Jim > said that an amplifier is needed to use an electret element. Well, I > picked up Item# 270-090 from Radio Shack today. > > http://www.radioshack.com/product/index.jsp?summary=summary&techSpecs=techSpecs¤tTab=techSpecs&cp=&custRatings=custRatings&features=features&accessories=accessories&productId 62215&support=support&tab=summary > > > It has a wiring diagram on the back of the package that seems to > indicate that the single transistor amplifier is already built into the > package. I was going to ask if that was in fact what it indicates, and > inquire whether it would work with the RST-443 intercom. Then I got > antsy and just went and tried it. With only two leads, you know I had > to hook it up backwards and feel disappointed for a minute until I > figured out to turn the leads around. Then it was "WOOHOO!!" all the way. > > I'm now well on my way to having the equivalent of a $500, in-the-ear > headset, and it's only costing me about $50. (Testing is incomplete, > but others have reported resounding success.) > > ________________________________ Message 4 _____________________________________ Time: 09:39:54 AM PST US From: "John Burnaby" Subject: Re: AeroElectric-List: DIY - In the ear headphones Ernest, Does the ANR portion of the Phillips headphone still function after your tweaking? And how do you suspend the mike? I am enamored of the Lightspeed Mach One, but if one can home brew the same thing for $50, I might become an electronerd yet! John ________________________________ Message 5 _____________________________________ Time: 11:27:33 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: DIY - In the ear headphones John Burnaby wrote: > Ernest, > > Does the ANR portion of the Phillips headphone still function after > your tweaking? The ANR sits between the plug and the speaker. I've not verified it yet, but none of the tweaking I'm attempting should affect the ANR function at all. > And how do you suspend the mike? > Flox to the end of piano wire that wraps around your head. For maximum clarity, you want to encase the mic in a box with just one tiny hole directed at your mouth. Basically, you want to block sound from all directions, except where your voice is coming from. I'm still working on this part. ________________________________ Message 6 _____________________________________ Time: 02:13:33 PM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: DIY - In the ear headphones Actually the "tin can with a hole in one end" approach to microphone design will give you an omnidirectional mic, which although intuitive, is not what you need. See http://www.prosoundweb.com/install/spotlight/cardioid/cardioidmics.shtml for how a unidirectional mic is made. Best regards, Rob Housman Irvine, California Europa XS Tri-Gear S/N A070 Airframe complete -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest Christley Sent: Tuesday, July 24, 2007 11:24 AM Subject: Re: AeroElectric-List: DIY - In the ear headphones > And how do you suspend the mike? > Flox to the end of piano wire that wraps around your head. For maximum clarity, you want to encase the mic in a box with just one tiny hole directed at your mouth. Basically, you want to block sound from all directions, except where your voice is coming from. I'm still working on this part. ________________________________ Message 7 _____________________________________ Time: 02:46:26 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Double-shielded coax At 07:43 PM 7/22/2007 -0400, you wrote: > >Can someone explain the benefits of double-shielded coax cable? > >A friend of mine mentioned it's either a requirement or strongly suggested >when doing the GNS430 WAAS upgrade - so what happens, does it help reduce >line loss and/or does it really reduce EMI? Double shielding has some exceedingly small benefits to propagating radio frequency energy from point A to point B through exceedingly RF noise environments. Since GPS transmitted signals are below ambient noise, it's a good idea not to "waste" your system's inherent signal to noise ratio with a potentially degraded feedline installation. Now, having said that, it's unlikely that anyone crafting an OBAM aircraft will realized benefit from the double shielding. The major jump in coax quality for RG400 vs. RG58 is modern, higher temperature, environmentally robust insulations. PVC and Polyethylene were whippy-do materials in WWII, but cousins to teflon are the materials of choice today. The choice is not so much one of performance as-installed but one of longevity in service combined with doing the best we know how to do. It's similar to the evolution in finishes. Nobody would consider painting their airplane with cellulose based dope (al la Hindenberg) no matter how good it looks when compared to an equally fresh coat of Imron. >Also, we were discussing whether it'd be beneficial to use double shielded >from the mag p-lead -> key switch -> mag ground and then subsequently >grounding the outer-most shield to the airframe. I wasn't sure where to >stand with this concept as I thought the idea of using a single shielded >wire isolated from the A/C ground enabled current pulses going opposite ways >to cancel most noise. No. Shielding in these applications are for mitigation of ELECTROSTATIC coupled noises and there is no benefit to using double shielded coax for p-leads. Ground as shown in the z-figures at the engine end only. Bob . . . ---------------------------------------- ( "Physics is like sex: sure, it may ) ( give some practical results, but ) ( that's not why we do it." ) ( ) ( Richard P. Feynman ) ---------------------------------------- ________________________________ Message 8 _____________________________________ Time: 02:47:38 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Avionics master switch/relay At 10:07 PM 7/22/2007 +0100, you wrote: Or how about wiring per figure on page 4 of http://aeroelectric.com/articles/avmaster.pdf Bob . . . >Ed, > > >If you still want to use an avionics master after reading all Bob has >written you could try using 2 avionics buses, each energized by a relay >both of which are switched by one double pole switch. Put your essential >avionics on one bus and provide that with power direct from the battery >via an emergency switch and diode. If the emergency switch is a double >pole item also it could control power to your essential/endurance, non >avionic, bus as well. Please be aware that the parts count has gone up and >reliability has probably gone down, and I have not tried this set up. > > >Yours, Peter > > >-----Original Message----- >From: owner-aeroelectric-list-server@matronics.com >[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of >jedwood@earthlink.net >Sent: 21 July 2007 15:57 >To: aeroelectric-list@matronics.com >Subject: AeroElectric-List: Avionics master switch/relay > > >I am wanting to use an avionics master switch or relay with my electrical >system. My question is: Do I need to put all of my avionics on a separate >bus then control the power to that bus by the avionics master? Also,what >if I want just a portion of my avionics on my endurance bus? I have looked >at all of the Z figures and cannot find an example. > > >Thanks in advance for your help. > > ________________________________ Message 9 _____________________________________ Time: 02:56:22 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: http://smartaircraftsystems.com/ There's a bunch of new electrical system management products coming on line these days. I've consulted for several manufacturers of such products. The question to be asked and answered is what is the $cost$ to save how much $time$ and at what reduction in system reliability - particularly with respect to single points of failure propagating across multiple systems. What are the weight penalties and perhaps most importantly, if one decides to stay with traditional management techniques and philosophies, what other useful electro-whizzy could be purchased with dollars not invested for added convenience or "gee whiz". Without arguing for or against such systems, I would encourage every potential user to deduce for themselves the return on investment in the product for how they intend to use the airplane while keeping in mind an old adage my grandfather might have offered . . . "Sometimes the best way to drive a nail is with a hammer." Bob . . . At 03:15 PM 7/22/2007 -0400, you wrote: >List, > >This new product just popped up on the radar. What do you all think, does >it show potential? > >Jerry Cochran > > >Here is the web site for the new Smart Aircraft Management Systems, "SAMS" > >http://smartaircraftsystems.com/ > >Still preliminary and lots of housekeeping and text editing but its >basically complete. > >This is a all solid state electrical system with no relays mechanical CB, >fuses, or contactors in the power path from the battery (s) to the end user >equipment, Integrated into this system is a complete fault detection and >warning system that includes relational logic to detect and warn if two or >more monitored conditions exist that alone is not a fault but the specific >combination of conditions will generate a fault. Both Visual and Audible >warnings are available. This fault detection system includes the ability to >have different levels of limit checking and the modules are interconnected >using the automotive type CAN serial bus. This fault system is independent >of the hardwired electrical power system for reliability. With solid state >switches and built in over current protection the result is a simple to wire >electrical system. Its been in work for several years. > >Feel free to ask questions. > >Paul > > >---------- >Get a sneak peek of the all-new >AOL.com. > > http://www.matronics.com/Navigator?AeroElectric-List > > >incoming mail is certified Virus Free. >Checked by AVG. Bob . . . ---------------------------------------- ( "Physics is like sex: sure, it may ) ( give some practical results, but ) ( that's not why we do it." ) ( ) ( Richard P. Feynman ) ---------------------------------------- ________________________________ Message 10 ____________________________________ Time: 03:08:31 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Semi-Custom Products At 09:27 AM 7/22/2007 -0400, you wrote: > >Bob > >This may not fit into your philosophy of versatility but FWIW if I were in >the market for the LV/OV control board I would prefer to see the lights >and switch already mounted within the module. Second best would be a >pre-wired remote panel of lights and switch or at least the option of >purchasing those unassembled parts at the same time. I have learned that >it is nice to have all such remote assemblies of switches or lights easily >removeable as a unit for serviceability rather than mounted in individual >holes in the instrument panel. In addition where I've used a single DB >connector on a device for both power and a remote panel, I've found it >difficult to remove the remote panel for service or modification since the >connector is also hardwired to the aircraft. Keep in mind that the Do-Lots assembly is capable of being configured for a multitude of tasks . . . many of which may not even have lights and or switches. If I were addressing the single application cited, then yes, avoiding the remotely mounted electronics module would be desirable. One could always configure their own installation with the necessary and useful in-line connectors to accommodate a maintenance situation. >We have completed 130 flight hours with our Z-14 wired subaru now without >any nuisance OV trips. The only electrical issue is that I recently >purchased a comfortable David Clarke headset and with our fairly quiet >engine, I now hear weak but annoying strobe whine that I couldn't hear in >cruise with other headsets. I have already followed most of your wiring >recommendations so it may take me awhile to solve this one especially >since the strobes operate off a different alternator and battery as the >radio and intercom. Start with a test battery made up of a couple 6v lantern batteries to run the strobe supply with a short cable and batteries located right at the power supply. You need to deduce the propagation mode. I suspect it's conducted and a relatively simple filter at the power supply will fix it. Bob . . . ________________________________ Message 11 ____________________________________ Time: 03:46:37 PM PST US From: Ernest Christley Subject: Re: AeroElectric-List: DIY - In the ear headphones Rob Housman wrote: > > Actually the "tin can with a hole in one end" approach to microphone design > will give you an omnidirectional mic, which although intuitive, is not what > you need. See > http://www.prosoundweb.com/install/spotlight/cardioid/cardioidmics.shtml for > how a unidirectional mic is made. > > Boy, did you save me some rabbit chasing. I've now got all the pieces working (except the microphone housing), and I've had to do practically nothing. The Phillps ANR Earbuds come with a 1/4" adapter that will plug directly into the intercom. The sound is excellent. My intercom is mono, so I have some work to do there, but there's nothing to do otherwise. I have to add a 3/16" adapter to the end of the microphone, and I think a small bottle cap and a piece of foam double-sided tape will make it into a nice cardoid. The piano wire bends nicely around my ears and the back of my head, and is very comfortable with a little heatshrink added. ________________________________ Message 12 ____________________________________ Time: 04:23:11 PM PST US From: "Karl Ahamer" Subject: RE: AeroElectric-List: Solar Charger Hi Chris, I buildt one myself using a single voltage regulator LM338K and a couple of resistors and caps.LM338 is $10.- and will handle up to 5A.It provides a constant adjustable output voltage and keeps the battery charged. Karl Ahamer Mittagong/Australia -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Chris Byrne Sent: Tuesday, 24 July 2007 7:31 PM Subject: AeroElectric-List: Solar Charger I am wanting to purchase a solar powered charger that is compatible with an ODESSY battery. This will be used as a trickle charger/battery maintainer. By the way can you get a solar charger that will give a full charge and revert to trickle? Regards Chris Byrne SYDNEY 23/07/2007 7:45 PM 23/07/2007 7:45 PM ________________________________ Message 13 ____________________________________ Time: 05:16:19 PM PST US From: Charlie England Subject: Re: AeroElectric-List: DIY - In the ear headphones Ernest Christley wrote: > > > Rob Housman wrote: >> >> >> Actually the "tin can with a hole in one end" approach to microphone >> design >> will give you an omnidirectional mic, which although intuitive, is not >> what >> you need. See >> http://www.prosoundweb.com/install/spotlight/cardioid/cardioidmics.shtml >> for >> how a unidirectional mic is made. >> > Boy, did you save me some rabbit chasing. > > I've now got all the pieces working (except the microphone housing), and > I've had to do practically nothing. The Phillps ANR Earbuds come with a > 1/4" adapter that will plug directly into the intercom. The sound is > excellent. My intercom is mono, so I have some work to do there, but > there's nothing to do otherwise. I have to add a 3/16" adapter to the > end of the microphone, and I think a small bottle cap and a piece of > foam double-sided tape will make it into a nice cardoid. The piano wire > bends nicely around my ears and the back of my head, and is very > comfortable with a little heatshrink added. As someone else pointed out, a directional mic would be helpful. Also, building one starting with an omni is a non-trivial task. Buying an el-cheapo a/c headset or a used one & cannibalizing it for its mic *is* a trivial task. (You also get the proper mic connector in the bargain.) One the guys on an ultralite list I monitor is using ANR earbuds under his regular headset. He reports that noise reduction is really good. :-) Charlie ________________________________ Message 14 ____________________________________ Time: 05:27:45 PM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: DIY - In the ear headphones Yeah, maybe, but the rabbit is still hopping along. I pointed you to the theory but now you have to get the design to agree with theory. The trick is to calculate the time values in the referenced article so that the sound from the rear arrives at the front side of the diaphragm in phase with the sound from the front. The velocity of sound at 30 deg C is 350 meters/second. Best regards, Rob Housman Irvine, California Europa XS Tri-Gear S/N A070 Airframe complete -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest Christley Sent: Tuesday, July 24, 2007 3:43 PM Subject: Re: AeroElectric-List: DIY - In the ear headphones Rob Housman wrote: > > Actually the "tin can with a hole in one end" approach to microphone design > will give you an omnidirectional mic, which although intuitive, is not what > you need. See > http://www.prosoundweb.com/install/spotlight/cardioid/cardioidmics.shtml for > how a unidirectional mic is made. > > Boy, did you save me some rabbit chasing. I've now got all the pieces working (except the microphone housing), and I've had to do practically nothing. The Phillps ANR Earbuds come with a 1/4" adapter that will plug directly into the intercom. The sound is excellent. My intercom is mono, so I have some work to do there, but there's nothing to do otherwise. I have to add a 3/16" adapter to the end of the microphone, and I think a small bottle cap and a piece of foam double-sided tape will make it into a nice cardoid. The piano wire bends nicely around my ears and the back of my head, and is very comfortable with a little heatshrink added. ________________________________ Message 15 ____________________________________ Time: 05:48:30 PM PST US From: Charlie England Subject: Re: AeroElectric-List: DIY - In the ear headphones Charlie England wrote: > > > Ernest Christley wrote: >> >> >> Rob Housman wrote: >>> >>> >>> Actually the "tin can with a hole in one end" approach to microphone >>> design >>> will give you an omnidirectional mic, which although intuitive, is >>> not what >>> you need. See >>> http://www.prosoundweb.com/install/spotlight/cardioid/cardioidmics.shtml >>> for >>> how a unidirectional mic is made. >>> >> Boy, did you save me some rabbit chasing. >> >> I've now got all the pieces working (except the microphone housing), >> and I've had to do practically nothing. The Phillps ANR Earbuds come >> with a 1/4" adapter that will plug directly into the intercom. The >> sound is excellent. My intercom is mono, so I have some work to do >> there, but there's nothing to do otherwise. I have to add a 3/16" >> adapter to the end of the microphone, and I think a small bottle cap >> and a piece of foam double-sided tape will make it into a nice >> cardoid. The piano wire bends nicely around my ears and the back of >> my head, and is very comfortable with a little heatshrink added. > > As someone else pointed out, a directional mic would be helpful. Also, > building one starting with an omni is a non-trivial task. Buying an > el-cheapo a/c headset or a used one & cannibalizing it for its mic *is* > a trivial task. (You also get the proper mic connector in the bargain.) > > One the guys on an ultralite list I monitor is using ANR earbuds under > his regular headset. He reports that noise reduction is really good. :-) > > Charlie > > Well duhhh... Is it obvious that I waited until after posting to read the link? ________________________________ Message 16 ____________________________________ Time: 07:29:21 PM PST US From: Ernest Christley Subject: Re: AeroElectric-List: DIY - In the ear headphones Rob Housman wrote: > > Yeah, maybe, but the rabbit is still hopping along. I pointed you to the > theory but now you have to get the design to agree with theory. The trick > is to calculate the time values in the referenced article so that the sound > from the rear arrives at the front side of the diaphragm in phase with the > sound from the front. The velocity of sound at 30 deg C is 350 > meters/second. > Yeah, that's one way to go about it. Another method involves my Echelon headset and a pair of calipers 8*) ________________________________ Message 17 ____________________________________ Time: 09:13:23 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Off to OSH I'm offering two presentations at OSH this year. One on Thursday afternoon and the other on Friday night (open Q&A session). Dr. Dee is unable to accompany me on this trip so my father-in-law is coming along to share driving duties (and to find out what this OBAM aircraft thing is all about!). I'll be off line until Sunday. Hope we can meet some of you there! Bob . . . ---------------------------------------- ( "Physics is like sex: sure, it may ) ( give some practical results, but ) ( that's not why we do it." ) ( ) ( Richard P. 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