---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 03/24/12: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:04 AM - Re: Stobes (stearman456) 2. 07:03 AM - Re: Stobes (Eric M. Jones) 3. 10:10 AM - Re: Expanded horizons for the List?Marketing suggestion (Terry Watson) 4. 11:32 AM - Re: Re: wingtip vor antenna (Mark Harris) 5. 06:43 PM - Re: Expanded horizons for the List?Marketing suggestion (nuckollsr) 6. 07:11 PM - Re: Re: Expanded horizons for the List?Marketing suggestion (Neal George) ________________________________ Message 1 _____________________________________ Time: 05:04:29 AM PST US Subject: AeroElectric-List: Re: Stobes From: "stearman456" tperry(at)lvtofly.com wrote: > Advantage is less noise from the high voltage lines running the length of your airplane. Also your strobes are independent of one another, if you loose one power supply your other strobes still work. That makes sense - the kit with the three power supplies is slightly more expensive but I can afford the weight of the extra units. Flying an airplane with noisy strobes has always driven me nuts in the past. Any advice on building the ultimate in quiet strobe installations (Whelen A 490A,TS,CF Power Supplies) appreciated. Dan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=369286#369286 ________________________________ Message 2 _____________________________________ Time: 07:03:05 AM PST US Subject: AeroElectric-List: Re: Stobes From: "Eric M. Jones" Bob N. saiys: > I would offer that centralized > supplies are also qualified, i.e. have passed DO-160 > conducted and radiated emissions. So if installed with > attention to good practice for treatment of shields, > they should present no greater noise problem in an > OBAM aircraft than they do in a TC aircraft. I agree Bob, but the basic EMC rule of fixing the noise at its source is a good one, and this points in the direction of putting the HV very close to the strobe tubes. If a standard installation works well, that does not mean a global shift in design is unwise, particularly if some particular design has problems. Bob N. says: > All the strobes on turbine aircraft have local power > supplies but as you've noted, these are breathtakingly > expensive. This is interesting Bob. I wonder if there are some additional design forces at work here? > What kind of voltages/currents and duty cycles > are involved? I've seen some LED anti-collision > protects offered to HBC while I was still there but > folks who showed them to me were unable or reluctant > to discuss design details. > > What's the architecture for wiring up large arrays > of LED's. The tail strobe I saw had about 36 leds > in it. The guy thought it was 4 strings of 9 each. > At 4 volts per led in an overdriven pulse mode, > one comes to believe that a pulsed, 36 volt constant > current supply is used. What approach has been most > attractive in your experience? Bob, I try to stay away from boosted switch-mode LED supplies of any sort. The reason for these (one presumes) is that common lighting is often in strings that make difficult parallel wiring, or that parallel lights demand higher currents, which in some instances is difficult to achieve. But having only 12-28 voltage "Luminaries" allows designs of large parallelism. But this is simple on a PCB. My discontinued (but fabulous) LED position light was 4 strings of 3 (70 mA) LEDs. My LED tail light is a single beefy 1200 mA LED with a linear LM317 regulator. Totally EMC silent.* > I've sold perhaps 50 filtered supplies over the past 4-5 years > and perhaps half that number of filter boards for > folks who already had supply modules. > Bob . . . *As an aside. These supplies were Luxdrive Power Pucks (I don't think Luxeon is involved). You are to be congratulated on quieting these demons. I gave up and dissolved away the potting to examine the PCB. The design was quite clearly laid out by someone who had never taken a Kimmel Gerke course. I toyed with the notion of redesigning the device, but finally sold my shelf full of them on Ebay, converted all my designs to linears, and washed my hands of it. Some data and comments: The Whelen strobe anti-collision power supply output nominal is 550V. This fact alone would make distributed supplies a good design choice. Separate supplies at the tubes should theoretically weigh less if the supporting structure and wiring is included, but the comparison is hard to glean from the published Whelen data. Whelen has one spearate strobe supply that says "cannot be synchronized", which is weird when you understand how little it takes to do so. My "vapor-ware" design uses a parallel string of two RED leds. Oddly, the FAA has had a long love affair with neon tubes since the 1930s, so red is a permissible color and red LEDs have the highest efficiency. (But the human visual response is best at 555 nm yellow green...the color under the African jungle canopy). Xenon blue-white strobes are easy to make. (A side note for your kid's science project...Radon should make great flash tubes..unfortunately all radon isotopes are radioactive.) But I digress.... My design uses an array of red LEDs for 12V, and a parallel array of 4 for 28V. powered by small local supercaps (hey, why not?). Each LED "strobe lamp" is basically pulsed on and off and synchronized by a central circuit the size of a postage stamp. The power to the LED strobes is the same as the position lights. I would gladly publish the circuit but it is incomplete...as is my Glastar, which I'd better start working on. My electro-whizzie work has slowed down since I spend much of my time selling switch guards. NASCAR is also a big market. See attached. (The Redbull team was so secret at first I thought they had to be spooks!) -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=369288#369288 Attachments: http://forums.matronics.com//files/redbull_2_156.jpg ________________________________ Message 3 _____________________________________ Time: 10:10:15 AM PST US Subject: Re: AeroElectric-List: Expanded horizons for the List?Marketing suggestion From: Terry Watson Bob, I was so pleased to see you mention the Khan Academy. It is a great example - as is your aeroelectric list - of the extraordinary but becoming ordinary benefits of modern information technology. To you and those of your readers who might want to avoid being blind-sided by the accelerating rate of change of our probable future, I want to recommend a new book: "Abundance: The Future is Better Than You Think", by Peter Diamandis. I don't think I have read anything in the 32 years since Alvin Toffler's "The Third Wave" that made me more excited and optimistic about the near future. To add a note of credibility to the Abundance book for aeroelectric list subscribers, Peter Diamandis is the man who created the X prize that inspired Paul Allen to finance Burt Rutan to put the first private astronauts into space. He has gone on to create other X prizes which you will read about in the book. What's so amazing is how rapidly the very high bar set for the prizes is being achieved. Just Google "Abundance" and you will find links to the book's website and to Amazon if you want to read reviews or buy it. Terry RV-8A stalled Seattle ________________________________ Message 4 _____________________________________ Time: 11:32:00 AM PST US Subject: Re: AeroElectric-List: Re: wingtip vor antenna From: Mark Harris Hi Bob Just another quick question I fabricated the parts for the VOR antenna today.is it ok to alocrom the parts before assembly and then would paint etch prime be ok ,I would bear the connection points. Thanks Mark Rent our beautiful 3 bedroom luxury villa in Orlando, Florida. View our virtual tour but book direct with us. See the link below:- http://www.florida1strentals.com/property.php?id=21 Contact Emma and Mark Harris 01582 529820 harrisfloridavilla@hotmail.com On 21 Mar 2012, at 01:50, "Robert L. Nuckolls, III" wrote: > > At 02:18 PM 3/20/2012, you wrote: >> >> Cheers Bob >> >> Looks like a job for the weekend > > Do you have access to an antenna analyzer or > at least an SWR meter? > > > Bob . . . > > > > > ________________________________ Message 5 _____________________________________ Time: 06:43:59 PM PST US Subject: AeroElectric-List: Re: Expanded horizons for the List?Marketing suggestion From: "nuckollsr" Thank you for the recommendation. I'll get it. Speaking of "abundance', I'm finding it easy to be overwhelmed by the quantity and scope of good data available off the 'net for the time and effort to download . . . THEN comes the investment of time to absorb it. I had seen some of Milton Friedman's work in 10 minute chunks . . . but somebody turned me on to "Free to Choose" in 10 segments and downloadable from YouTube. I captured all the videos and now need to get them watched. I think I may strip off the audio so I can listen to them in the car. I do spend a lot of time on the road these days. Dr. Dee turned me onto Kahn. She too has an intense interest in the video mini-lecture technique. There are a few important points in her statistics classes that are common stumbling blocks for some students. While fully willing to explain the material again, students who are already on board are not too happy about 'back tracking'. We've decided to do some mini-lectures on those sicking points that can be accessible to any Bethany student 24/7. The hope is that these productions will bring the lagging students up at their own speed/convenience, provide good review for the rest, and make progress in the class room match the syllabus. We have similar situations here on the List in what has been called 'frequently asked questions'. An exciting 'new' concept, at least for me. Once I'm comfortable with the mechanics of production and we have Dr. Dee's most pressing needs addressed, I'll be looking for suggestions from folks here on the List for topics to be 'canned' in a similar fashion. Thanks for the tip! Bob . . . Read this topic online here: http://forums.matronics.com/viewtopic.php?p=369311#369311 ________________________________ Message 6 _____________________________________ Time: 07:11:56 PM PST US From: "Neal George" Subject: RE: AeroElectric-List: Re: Expanded horizons for the List?Marketing suggestion Bob - care to share that link? neal -----Original Message----- From: nuckollsr I had seen some of Milton Friedman's work in 10 minute chunks . . . but somebody turned me on to "Free to Choose" in 10 segments and downloadable from YouTube. 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