---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 05/29/03: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:39 AM - Re: XPDR antenna question (Gilles.Thesee) 2. 07:10 AM - Re: XPDR antenna question (Robert L. Nuckolls, III) 3. 07:21 AM - The loss of a horseshoe nail (Fergus Kyle) 4. 07:50 AM - King GNS-80 (Chris Stone) 5. 08:39 AM - Re: The loss of a horseshoe nail (Robert L. Nuckolls, III) 6. 12:07 PM - My Fuel Gauge Design and Linearizing (Eric M. Jones) 7. 03:36 PM - Re: Alternator noise on Grumman (Robert L. Nuckolls, III) 8. 07:52 PM - Re: King GNS-80 (James Freeman) 9. 09:12 PM - RFI (Kevin and Marlys Cocozzoli) 10. 11:03 PM - Re: RFI (James E. Clark) 11. 11:22 PM - Re: RFI (Kevin and Marlys Cocozzoli) ________________________________ Message 1 _____________________________________ Time: 01:39:28 AM PST US From: "Gilles.Thesee" Subject: Re: AeroElectric-List: XPDR antenna question --> AeroElectric-List message posted by: "Gilles.Thesee" > > > >Does it look better now ? > >http://gilles.thesee.free.fr/temp/DSCF1550.JPG > >http://gilles.thesee.free.fr/temp/DSCF1554.JPG > >http://gilles.thesee.free.fr/temp/DSCF1555.JPG > > That's it! > Bob, Thanks once more for the knowledge you share with us, and the swiftness of your answers. Regards, Gilles ________________________________ Message 2 _____________________________________ Time: 07:10:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: XPDR antenna question --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:47 PM 5/28/2003 -0400, you wrote: >On Wed, 28 May 2003 17:53:43 -0500 > "Robert L. Nuckolls, III" wrote: >> RF goes around corners . . . a radial that is physically >> 1/4 wave length over all still has a low impedance node >> at the base of the antenna if some portion of the end >> takes a 90 degree turn. >> >> "Ground plane" means that you're looking for a zero-ohms >> connection to free space at the end of the transmission >> line for the coax shield connection. If the base impedance >> of a 1/4 wave is on the order of 30 ohms, then 4 radials >> paralleled gives you a 'ground' impedance of about 7 ohms, >> 10 radials would be 3 ohms, etc. One can imagine that >> a disk is made of an infinite number of radials in parallel >> for an ideal 'ground' impedance approaching zero ohms. >> >> Obviously simplistic, there are some additional effects that >> keep us from getting zero but for all practical purposes, >> we can get quite close . . . the overall shape of those 1/4 wave >> radials is not terribly critical. It's length from base of antenna >> to the edge irrespective of shape . . . that's the "magic" of >> a circular ground plane as opposed to a square one . . . square >> gets you 4 radials at the right length and a bunch of others >> too long. Circular makes them all the same length. > >I *think* square - with the dimention a touch undersize - gets you 8 >radials the right length, and an infinite number a little long or a little >short. A hexagon would get you 12 accurate radials, etc. Yup, that's right too . . . >If your diameter is just right, then yes, you have an infinte number of >accurate radials. But what exactly is that diameter? And if you're off >by (say) .125" on a circular ground plane, you have NO accurate >radials. In that case would you be better off with a square or hexagonal one? When you see a vertical antenna with ground plane radials under it perched on top of some tower or building, it's not uncommon to have just 4 radials . . . and as mentioned above, this gives you a "ground impedance" about 1/4th that of the antenna . . . adding more "perfect" radials has a diminishing return on the effort . . . adding 4 more radials only improves on the original 4 by a few percent. Doubling the number again gives you the same percentage improvement. From a power transfer perspective, the guy at the other end would not perceive any improvement in your signal by jumping from 4 to an infinite number of radials. Radiation pattern is also affected by ground plane area and it's shape. You often see radials "drooped" downward. This has two beneficial effects. It raises the matching impedance of the antenna to more nearly equal 50-ohm coax and lowers the radiation angle from approx 45 degrees to some pattern more nearly on the horizon. >Or do I misunderstand - is the 1/4 wave length the minimum, or the optimum? It's "optimum" . . . for a 1/4 wave radial is "tuned" to the frequency of interest. You can get similar performance with 3/4 or any other odd multiples of quarter wave . . and once you're out more than a wavelength or two, you have what's called an "infinite ground plane" wherein actual size variations have no measurable effect on antenna characteristics. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:21:17 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: The loss of a horseshoe nail --> AeroElectric-List message posted by: "Fergus Kyle" Bob, Off the topic - somewhat. I just couldn't stop sending this - your analogy of the lost horseshoe nail and designing a three-legged horse which could fight is a luxurious and creative one of the best. I don't think we'll ever forget the mental corridor we'll travel in future..................... A milestone. Ferg ________________________________ Message 4 _____________________________________ Time: 07:50:01 AM PST US Subject: AeroElectric-List: King GNS-80 From: "Chris Stone" --> AeroElectric-List message posted by: "Chris Stone" Hello all, This may be slightly off topic but there may be others with a similar nagging query... I am collecting instruments and avionics as I construct my RV-8 in an effort to spread the costs over time and to take advantage of "deals" as I come across them. Does anyone have experience with the King KNS-80? This is an all in one unit that incorporates VOR/LOC/GS/DME in one box. From a panel space and installation standpoint it has advantages. From a reliability standpoint it would seem to be a single point failure item. Narco has a similar unit (122 D) with VOR/LOC/GS. OBS/LOC/GS indicators: Is there a standard I/O from receiver to indicator or does each manufacturer have their own signal/data I/O? If they are manufacturer specific is each manufacturer consistent or does each manufacturer have variants within their own product lines? i.e. can I use a Sperry indicator with a King receiver? Antennas... I have followed the discussions on antennas and have decided to go with the Sportcraft VOR/COM wingtip antenna. Can this also be used for the Localizer? I have a Marker Beacon and Transponder antenna. Will I need a separate Glide Slope antenna? I would like to keep the airframe clean i.e. no antennas hanging everywhere. If a separate GS antenna is required can it be mounted inside the fiberglass wingtip? I realize I have posted questions that my require lengthy answers... This is my primary source for aircraft/avionics expertise, and a good one it is! Thanks! Chris Stone RV-8 - wings Slowly drying out in Oregon ________________________________ Message 5 _____________________________________ Time: 08:39:26 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: The loss of a horseshoe nail --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:22 AM 5/29/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Fergus Kyle" > >Bob, > Off the topic - somewhat. > I just couldn't stop sending this - your analogy of the lost >horseshoe nail and designing a three-legged horse which could fight is a >luxurious and creative one of the best. I don't think we'll ever forget the >mental corridor we'll travel in future..................... > A milestone. Thank you for your kind words sir . . . Bob . . . ________________________________ Message 6 _____________________________________ Time: 12:07:34 PM PST US From: "Eric M. Jones" Subject: AeroElectric-List: My Fuel Gauge Design and Linearizing --> AeroElectric-List message posted by: "Eric M. Jones" Here's the plan: I have every faith in fuel flow rate but realize the need for fuel gauges. I like the elegance of the capacitive sensors but not their complexity. So how about this-- Put ten tiny tiny tiny 0805 size PTC thermistors on a flex circuit with a Gortex sleeve over it. Arrange these logarithmically so that they can be read-out by a 10-led bar graph. Stuff it through a 1/4" rivnut installed in each tank. On the instrument panel, 10 leds100%, 9 leds70.7%, 8 leds50%, 7 leds35.4%, 6 leds+ 25%, 5 leds17.7%, 4 leds12.5%, 3 leds8.8%, 2 leds6.2%, 1 led4.4%. Use an LM3915 display driver. Greater precision as the fuel is depleted. This makes enormous sense, since no one cares how much they have when they are full of fuel. This also makes up for using the bar graph. Now where does the FAA required "Red radial line marking zero" go? I just don't know. PS- There is one Powerlink 1280 Amp solid state starter battery contactor flying (on a dual battery split system). Seems to be working perfectly. I am making a new run of an updated and improved design. This is still in a test phase, but versions of the new design will be for sale assuming all goes well in the testing. Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "Nothing is too wonderful to be true." - James Clerk Maxwell, discoverer of electromagnetism "Too much of a good thing can be wonderful." - Mae West, discoverer of personal magnetism ________________________________ Message 7 _____________________________________ Time: 03:36:49 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Alternator noise on Grumman --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:14 PM 5/28/2003 +0000, you wrote: >Below is the result of your inquiry. It was submitted by >Fred Hardy (frederick.a.hardy@boeing.com) on Wednesday, May 28, 2003 at >11:14:57 > >Wednesday, May 28, 2003 > >Fred Hardy > >, >Email: frederick.a.hardy@boeing.com >Comments/Questions: Hi Bob, My '78 Grumman Tiger has a loud whine coming >from the alternator through the headsets. I had the alternator checked at >annual (4/03)and the IA stated the brushes were about 50% worn. Also a new >filter was installed in 2002. The unit charges the battery without any >problems. The alternater is original equipment (25 years/1200 >hours). I've been reading up on this and it seems that I have a bad >diode(s). Should I have the unit totally rebuilt or just have the diodes >replaced? You need to load test the alternator. You can do this with a battery tester before you take it off the airplane. Put a voltmeter on the bus. With engine running at or near 2000 rpm, bring alternator on and increase load on battery up to the rating of the alternator. If you can get more than 1/2 or 2/3rds rating of alternator without drooping the bus to less than 13.0 volts, then your diodes are okay. Did this problem just crop up? Was it after the annual? I will invite you to join us on the AeroElectric List to continue this and similar discussions. It's useful to share the information with as many folks as possible. You can join at . . . http://www.matronics.com/subscribe/ Thanks! Bob . . . |---------------------------------------------------| | A lie can travel half way around the world while | | the truth is till putting on its shoes . . . | | -Mark Twain- | |---------------------------------------------------| ________________________________ Message 8 _____________________________________ Time: 07:52:20 PM PST US Subject: Re: AeroElectric-List: King GNS-80 From: James Freeman --> AeroElectric-List message posted by: James Freeman On Thursday, May 29, 2003, at 09:49 AM, Chris Stone wrote: > s anyone have experience with the King KNS-80? This is an all in one > unit that incorporates VOR/LOC/GS/DME in one box. From a panel space > and installation standpoint it has advantages. From a reliability > standpoint it would seem to be a single point failure item. > Narco has a similar unit (122 D) with VOR/LOC/GS. I've got over 700 hours behind one. Easy to use, dead reliable. Absolute state of the art...when Jimmy Carter was president. I recently talked to the new owner of my old Navion, and the unit still works flawlessly, but he'sthinking about upgrading. It is, however, an RNAV. Even a cheap GPS sort of makes the RNAV/DME redundant and has more utility. If it's the cheapest way you can get VOR/GS to shoot ILS approaches, and it's a smoking deal, I'd go for it. If you are VFR and just want to navigate, I think the biggest bang for the buck is a Northstar M-1 Loran. About a hundred bucks on e-bay and works great. JFF P.S. It occurs to me that my old Navion is near you, in Washington State. You might look up the registration for 2512T and see if he is ready to make the change. JFF ________________________________ Message 9 _____________________________________ Time: 09:12:25 PM PST US From: "Kevin and Marlys Cocozzoli" Subject: AeroElectric-List: RFI --> AeroElectric-List message posted by: "Kevin and Marlys Cocozzoli" Good Evening, I'm having trouble with radio interference in a Glasair III homebuilt I just finished and need some advice on what to look for. I'm not versed in avionics and there's no avionics shop at my airport. I have a UPSAT SL-30 Nav/Comm and SL-15 Audio Panel. The comm radio works fine in ground tests and with the engine running at low RPM I am both transmitting and receiving loud and clear. The problem surfaces when I increase the throttle to take off power. At approximately 2000 RPM my headset fills with static and I hear nothing but this static until I reduce RPM. Then everything's normal again. I was told by the kit maker that it may be the alternator. I pulled the alternator field circuit breaker but this had no effect. I would like to know what else I should look for as I have no idea why the radio would work fine until I advance the throttle. Tower states their not hearing the static so it's purely internal. Thank you very much for any help you can provide. Sincerely, Kevin Cocozzoli 210-666-6713 ________________________________ Message 10 ____________________________________ Time: 11:03:49 PM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: RFI --> AeroElectric-List message posted by: "James E. Clark" Are you very familiar with the **digital** setting of the squelch and other items on radio (I and friends have the SL-40). There are certain incantations spelled out in the manual that once done make a lot of sense but when you read the first time may seem a little strange. Suggestion: Take a pilot friend up for a flight and while one of you is flying the plane, the other take the manual and make adjustments with the headsets that you are normally going to use. Of course you could do this on the ground but the noise will be slightly differnt and you will be running your engine for some time at 2000 RPM+ without the benefit of cooling and scenery. Just a thought. James > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Kevin > and Marlys Cocozzoli > Sent: Friday, May 30, 2003 12:12 AM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: RFI > > > --> AeroElectric-List message posted by: "Kevin and Marlys > Cocozzoli" > > Good Evening, > > I'm having trouble with radio interference in a Glasair III > homebuilt I just > finished and need some advice on what to look for. I'm not versed in > avionics and there's no avionics shop at my airport. > > I have a UPSAT SL-30 Nav/Comm and SL-15 Audio Panel. The comm radio works > fine in ground tests and with the engine running at low RPM I am both > transmitting and receiving loud and clear. The problem surfaces when I > increase the throttle to take off power. At approximately 2000 RPM my > headset fills with static and I hear nothing but this static > until I reduce > RPM. Then everything's normal again. > > I was told by the kit maker that it may be the alternator. I pulled the > alternator field circuit breaker but this had no effect. I would like to > know what else I should look for as I have no idea why the radio > would work > fine until I advance the throttle. Tower states their not hearing the > static so it's purely internal. > > Thank you very much for any help you can provide. > > Sincerely, > > Kevin Cocozzoli > 210-666-6713 > > ________________________________ Message 11 ____________________________________ Time: 11:22:13 PM PST US From: "Kevin and Marlys Cocozzoli" Subject: Re: AeroElectric-List: RFI --> AeroElectric-List message posted by: "Kevin and Marlys Cocozzoli" Thanks James, I'll look into the manual. However, since this static starts at 2000 RPM, I obviously can't fly the plane until I get this worked out on the ground. I can't hear anything but static! But I'll check the manual...I should've thought of that. Thanks, Kevin ----- Original Message ----- From: "James E. Clark" Subject: RE: AeroElectric-List: RFI --> AeroElectric-List message posted by: "James E. Clark" Are you very familiar with the **digital** setting of the squelch and other items on radio (I and friends have the SL-40). There are certain incantations spelled out in the manual that once done make a lot of sense but when you read the first time may seem a little strange. Suggestion: Take a pilot friend up for a flight and while one of you is flying the plane, the other take the manual and make adjustments with the headsets that you are normally going to use. Of course you could do this on the ground but the noise will be slightly differnt and you will be running your engine for some time at 2000 RPM+ without the benefit of cooling and scenery. Just a thought. James > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Kevin > and Marlys Cocozzoli > Sent: Friday, May 30, 2003 12:12 AM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: RFI > > > --> AeroElectric-List message posted by: "Kevin and Marlys > Cocozzoli" > > Good Evening, > > I'm having trouble with radio interference in a Glasair III > homebuilt I just > finished and need some advice on what to look for. I'm not versed in > avionics and there's no avionics shop at my airport. > > I have a UPSAT SL-30 Nav/Comm and SL-15 Audio Panel. The comm radio works > fine in ground tests and with the engine running at low RPM I am both > transmitting and receiving loud and clear. The problem surfaces when I > increase the throttle to take off power. At approximately 2000 RPM my > headset fills with static and I hear nothing but this static > until I reduce > RPM. Then everything's normal again. > > I was told by the kit maker that it may be the alternator. I pulled the > alternator field circuit breaker but this had no effect. I would like to > know what else I should look for as I have no idea why the radio > would work > fine until I advance the throttle. Tower states their not hearing the > static so it's purely internal. > > Thank you very much for any help you can provide. > > Sincerely, > > Kevin Cocozzoli > 210-666-6713 > >