---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 03/30/12: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:40 AM - expanded horizons (Glen Matejcek) 2. 07:18 AM - Antennae materials (Eric M. Jones) 3. 08:39 AM - Re: Antennae materials (Robert L. Nuckolls, III) 4. 09:11 AM - Re: Uneven dipole elements (Robert L. Nuckolls, III) 5. 10:46 AM - Re: Uneven dipole elements (Mike Wynn) 6. 11:14 AM - Re: Uneven dipole elements (Dave Saylor) 7. 11:17 AM - Re: Uneven dipole elements (Robert L. Nuckolls, III) 8. 11:42 AM - Re: Uneven dipole elements (Robert L. Nuckolls, III) 9. 02:30 PM - Re: HID lighting observations (Brantel) 10. 03:58 PM - Re: Re SWR Meter? (Noel Loveys) 11. 04:19 PM - LED WigWag with B&C SSF-1 (Michael Ashura) 12. 04:48 PM - Re: Uneven dipole elements (Noel Loveys) 13. 06:48 PM - Correction (Michael Ashura) 14. 09:37 PM - Re: Uneven dipole elements (Robert L. Nuckolls, III) 15. 11:35 PM - Re: Uneven dipole elements (Dave Saylor) ________________________________ Message 1 _____________________________________ Time: 02:40:29 AM PST US From: Glen Matejcek Subject: AeroElectric-List: expanded horizons Hi Bob- Just in case you're not familiar, the EAA has a series of shorts available online called Hints for Homebuilders. It is quite a collection of how-to's. I don't know what the implications for intellectual property or aero politics would be if one participated there, but they certainly have the venue aspect nailed. FYI- Glen Matejcek ________________________________ Message 2 _____________________________________ Time: 07:18:22 AM PST US Subject: AeroElectric-List: Antennae materials From: "Eric M. Jones" First a word on the performance of electronic materials: We all know that materials have a DC bulk resistivity that is a measure of how they transfer electrons through the material. But for high frequency applications another characteristic is critical: Most dielectric materials are made of molecules with polar configurations that is, their constituent molecules have shapes where their atoms tend to be non-symmetrically attached. Thus these molecules will twist to try to align with electromagnetic fields imposed on them. A microwave oven is a good example. Water is somewhat bipolar, and an imposed electromagnetic wave causes the water molecule to change its orientation every cycle, thus producing mechanical heating--and cooking your food. If you were trying to build a PCB for 2.45 GHz, the common household microwave-oven frequency, water, or anything that absorbed water, or anything that was somewhat molecularly-similar to water would be a poor choice. The materials needed for antennas and PCBs have many structural and environmental constraints (strong enough, reasonably high temperature, no asbestos, waterproof, flame retardant, machinable, etc.) but are critically restrained by the requirement that the molecules making up the material not oscillate much at the frequencies to be used. The molecular shape (to over-simplify), and how well they are locked into the material is the key. This usually limits the commercial material selection to thermosetting materials like phenolic and Bakelite or high-pressure thermosetting resins like epoxies. When faced with building PCB or antenna supports or other high-frequency electronic parts, many people rely on some very old and august information. Much of this was compiled over half-a-century ago, and while one can appreciate its particular no-nonsense clarity, it misses all the recent advances. This has many negative affects: Poor material selections drive production prices up and structural dependability down. Time is wasted pursuing arcane magic materials invented decades ago and now largely unobtainablewhile simple to use, cheap and easily-sourced materials are available. See: Good History! Tables of Dielectric Materials. Wright Laboratories, Feb 1944 http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA288986 Here is a good and much more recent description of the choice of materials. http://www.speedingedge.com/PDF-Files/tutorial.pdf The recent discussion of searches for micarta, paper phenolic and Bakelite is a case in point. While these materials had their day, modern designs are almost entirely PCB materials like FR-4, (which almost universally replaced G10 and most other G- and FR- materials). So thats the story: Abandon your search for half-century old materials and use FR-4 glass epoxy. MSC Hardware is a great source for machining stock, but if you have a PCB fabricating house nearby, ask to grab some from their dumpster (thats how I do it). -------- 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=369609#369609 ________________________________ Message 3 _____________________________________ Time: 08:39:38 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Antennae materials > >So thats the story: Abandon your search for >half-century old materials and use FR-4 glass >epoxy. MSC Hardware is a great source for >machining stock, but if you have a PCB >fabricating house nearby, ask to grab some from >their dumpster (thats how I do it). Well stated but with one caveat. The dielectric constant for FR-4 versus the filled phenolic may be different. Probably is . . . but haven't had time to research/test it. This was the driving thought for getting my hands on a production example of the subject antenna. Direct measurement of the gamma-match capacitor fabricated from production parts yielded a value of 34 pF. This becomes the benchmark for substitution of materials. The choices are many but in this instance, they are not an apples-for-apples substitution. I'm considering the use of 1/32" copper clad for fabrication of a similar antenna. The copper lends itself to soldered joints (gas tight for centuries). The double-sided cladding offers an opportunity to craft the gamma-match strut from a single piece of FR-4 with copper bonded to both sides. Just another interesting project for the future . . . perhaps we can get to it before VOR goes the way of A-N Range stations. Bob . . . ________________________________ Message 4 _____________________________________ Time: 09:11:09 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Uneven dipole elements At 12:39 AM 3/30/2012, you wrote: >>Can't you splice it back on?<< Short answer--no. We had to lop the tip off a vertical stab to make room for more rudder horn on a Lancair ES. I didn't stop to think about an internal antenna. I shoulda. If the structure needed to be shortened . . . and the antenna is embedded in structure, would it have made any difference? On further inspection, the antenna seems to have three elements. Two run up each side of the Vstab trailing edge, aft of the stern post. They're embedded in the fiberglass and are nearly equal in length. Do you have any documentation on how this antenna was installed? I'm having trouble putting my gray-matter around your description. The element that was cut off is 8" forward of the Vstab trailing edge. I can't tell exactly how the three segments are connected. The aft-most two elements are visible through the fiberglass when the rudder is removed. I can see a lot of the cut element using a boroscope inside the Vstab. Would I hurt the radio to try transmitting and receiving? If this isn't easy to fix, we have the option of installing a belly-mounted replacement antenna using a spray-on ground plane. Get an SWR meter and see how bad the crippled antenna really is. Spray-on ground planes are like using Kleenex for wing fabric. Metallic radials on inside of skin is both the best and least we know how to do. Bob . . . ________________________________ Message 5 _____________________________________ Time: 10:46:09 AM PST US From: "Mike Wynn" Subject: Re: AeroElectric-List: Uneven dipole elements Bob, This ant design sounds like the one I spoke about. BTW: I found the diagrams and factory instructions, finally. Will scan and send today. Maybe it will help Dave S. with decision. GL! Mike Wynn Moab, UT ********** ----- Original Message ----- From: Dave Saylor To: aeroelectric-list@matronics.com Sent: Thursday, March 29, 2012 11:39 PM Subject: Re: AeroElectric-List: Uneven dipole elements >>Can't you splice it back on?<< Short answer--no. We had to lop the tip off a vertical stab to make room for more rudder horn on a Lancair ES.=C2 I didn't stop to think about an internal antenna.=C2 I shoulda. On further inspection, the antenna seems to have three elements.=C2 Two run up each side of the Vstab trailing edge, aft of the stern post.=C2 They're embedded in the fiberglass and are nearly equal in length. The element that was cut off is 8" forward of the Vstab trailing edge.=C2 I can't tell exactly how the three segments are connected.=C2 The aft-most two elements are visible through the fiberglass when the rudder is removed.=C2 I can see a lot of the cut element using a boroscope inside the Vstab. Would I hurt the radio to try transmitting and receiving?=C2 If this isn't easy to fix, we have the option of installing a belly-mounted replacement antenna using a spray-on ground plane. --Dave Saylor On Thu, Mar 29, 2012 at 7:45 PM, Robert L. Nuckolls, III wrote: At 05:30 PM 3/29/2012, you wrote: Bob, We managed to chop about 3 inches off the end of a dipole comm antenna. =C2 Would that have any appreciable effect on performance? =C2 Sure, but if I were to give you a 'number' . . . it wouldn't =C2 have much practical meaning. Is this an internal antenna? =C2 Can't you splice it back on? =C2 Bob . . . - ric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List MS - k">http://forums.matronics.com e - =C2 =C2 =C2 =C2 =C2 -Matt Dralle, List Admin. t="_blank">http://www.matronics.com/contribution ________________________________ Message 6 _____________________________________ Time: 11:14:23 AM PST US From: Dave Saylor Subject: Re: AeroElectric-List: Uneven dipole elements Thanks! I'd like to know what this antenna looks like. Off topic: It's on an as-yet unfinished Lancair ES with a 15-year old panel. It had a huge FMS-type display (that won't boot up) called a Avro-Tec FMP 300. The antenna in question is switched by a Comant gizmo between two comms. We stumbled back-asswards into an antenna engineer who works for L3 across the street from us. His hobby is helping ham operators build antennas, and he should be here Saturday to do a "sweep"...whatever that is. --Dave Saylor On Fri, Mar 30, 2012 at 10:45 AM, Mike Wynn wrote: > ** > Bob, > This ant design sounds like the one I spoke about. BTW: I found the > diagrams and factory instructions, finally. Will scan and send today. May be > it will help Dave S. with decision. GL! > Mike Wynn > Moab, UT > ********** > > ----- Original Message ----- > *From:* Dave Saylor > *To:* aeroelectric-list@matronics.com > *Sent:* Thursday, March 29, 2012 11:39 PM > *Subject:* Re: AeroElectric-List: Uneven dipole elements > > >>Can't you splice it back on?<< > > Short answer--no. > > We had to lop the tip off a vertical stab to make room for more rudder > horn on a Lancair ES.=C3=82 I didn't stop to think about an internal ant enna.=C3=82 > I shoulda. > > On further inspection, the antenna seems to have three elements.=C3=82 T wo run > up each side of the Vstab trailing edge, aft of the stern post.=C3=82 Th ey're > embedded in the fiberglass and are nearly equal in length. > > The element that was cut off is 8" forward of the Vstab trailing edge.=C3 =82 I > can't tell exactly how the three segments are connected.=C3=82 The aft-m ost two > elements are visible through the fiberglass when the rudder is removed. =C3=82 I > can see a lot of the cut element using a boroscope inside the Vstab. > > Would I hurt the radio to try transmitting and receiving?=C3=82 If this isn't > easy to fix, we have the option of installing a belly-mounted replacement > antenna using a spray-on ground plane. > > --Dave Saylor > > > On Thu, Mar 29, 2012 at 7:45 PM, Robert L. Nuckolls, III < > nuckolls.bob@aeroelectric.com> wrote: > >> nuckolls.bob@aeroelectric.com**> >> >> >> At 05:30 PM 3/29/2012, you wrote: >> >>> dave.saylor.aircrafters@**gmail.com > >>> >>> Bob, >>> >>> We managed to chop about 3 inches off the end of a dipole comm >>> antenna. =C3=82 Would that have any appreciable effect on performance? >>> >> >> =C3=82 Sure, but if I were to give you a 'number' . . . it wouldn't >> =C3=82 have much practical meaning. Is this an internal antenna? >> =C3=82 Can't you splice it back on? >> >> >> =C3=82 Bob . . . >> >> ====**=================== ===========**= >> - >> ric-List" target="_blank">http://www.matronics.com/** >> Navigator?AeroElectric-List >> ====**=================== ===========**= >> MS - >> k">http://forums.matronics.com >> ====**=====**= >> e - >> =C3=82 =C3=82 =C3=82 =C3=82 =C3=82 -Matt Dralle, List Admin. >> t="_blank">http://www.matronics.com/**contribution >> ====**=================== ===========**= >> >> >> >> > * > > href="http://www.matronics.com/Navigator?AeroElectric-List">http://www. matronics.com/Navigator?AeroElectric-List > href="http://forums.matronics.com">http://forums.matronics.com > href="http://www.matronics.com/contribution">http://www.matronics.com/c * > > * > =========== =========== =========== =========== > * > > ________________________________ Message 7 _____________________________________ Time: 11:17:56 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Uneven dipole elements At 12:45 PM 3/30/2012, you wrote: >Bob, >This ant design sounds like the one I spoke about. BTW: I found the >diagrams and factory instructions, finally. Will scan and send >today. Maybe it will help Dave S. with decision. GL! >Mike Wynn >Moab, UT Thank you! I'll post it to the reference documents folder on the website too. Bob . . . ________________________________ Message 8 _____________________________________ Time: 11:42:19 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Uneven dipole elements At 01:12 PM 3/30/2012, you wrote: >Thanks!=C2 I'd like to know what this antenna looks like. > >Off topic:=C2 It's on an as-yet unfinished >Lancair ES with a 15-year old panel.=C2 It had a >huge FMS-type display (that won't boot up) called a Avro-Tec FMP 300. > >The antenna in question is switched by a Comant gizmo between two comms. > >We stumbled back-asswards into an antenna >engineer who works for L3 across the street from >us.=C2 His hobby is helping ham operators build >antennas, and he should be here Saturday to do a "sweep"...whatever that is. A 'sweep' is done with a supper-whizzy network analyzer usually fitted the a sweep generator and graphical display for the output of the analyzer. You get pictures like this in seconds Emacs! Us poor guys use an SWR meter and variable frequency energy source to step through the frequencies of interest and record data. That data is then massaged like our algebra teachers taught us. After you've done it a few dozen times, any notions of it being a 'sweep' are replace the realization that it's really a 'plod'. It will be interesting to see what he finds. Take pictures of his test setup and data to share with us if you can. Bob . . . ________________________________ Message 9 _____________________________________ Time: 02:30:07 PM PST US Subject: AeroElectric-List: Re: HID lighting observations From: "Brantel" The newer HID ballast have circuitry to limit the inrush current. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=369637#369637 ________________________________ Message 10 ____________________________________ Time: 03:58:00 PM PST US From: "Noel Loveys" Subject: RE: AeroElectric-List: Re SWR Meter? I've used MFJ for years with no problems... HF and VHF. Noel From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Harley Sent: March 29, 2012 11:39 AM Subject: Re: AeroElectric-List: Re SWR Meter? Paul... Yep, still available...(a little more than you probably paid for it): www.mfjenterprises.com/Product.php?productid=MFJ-862 Harley I use my meter to check from time to time to verify all is well. This link has info on the meters http://www.eham.net/reviews/products/40?ehamsid=a9efc7e8e58a376ce24c0118effd 4579 The one I use is an MFJ-862 It has 2 needles for Forward and Reflected and will read watts for both. This is a low price unit, definately not a high, but had OK reviews. I have no idea if one can still buy it? PaulW ________________________________ Message 11 ____________________________________ Time: 04:19:52 PM PST US From: Michael Ashura Subject: AeroElectric-List: LED WigWag with B&C SSF-1 Bob, can I wire two LED landing and taxi lights per Page 3.0 (Ref DE 12/15/11) but using a single switch (already installed and labeled in unflown RV-6) as shown on Page 3.0 from 2003? Thank you ________________________________ Message 12 ____________________________________ Time: 04:48:46 PM PST US From: "Noel Loveys" Subject: RE: AeroElectric-List: Uneven dipole elements I'm wondering if it is now operating like a modified Windom antenna (not straight at centre and different length elements). I also would like to know if it is vertical or horizontal Noel -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: March 30, 2012 12:16 AM Subject: Re: AeroElectric-List: Uneven dipole elements --> At 05:30 PM 3/29/2012, you wrote: > > >Bob, > >We managed to chop about 3 inches off the end of a dipole comm antenna. >Would that have any appreciable effect on performance? Sure, but if I were to give you a 'number' . . . it wouldn't have much practical meaning. Is this an internal antenna? Can't you splice it back on? Bob . . . ________________________________ Message 13 ____________________________________ Time: 06:48:02 PM PST US From: Michael Ashura Subject: AeroElectric-List: Correction Previous post should read: (Revision -D- 12/15/11) ________________________________ Message 14 ____________________________________ Time: 09:37:48 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Uneven dipole elements At 06:46 PM 3/30/2012, you wrote: > >I'm wondering if it is now operating like a modified Windom antenna (not >straight at centre and different length elements). I also would like to >know if it is vertical or horizontal This would be a vertically polarized antenna and appears to be 1/2 wavelength. Is there enough 'bulk' at the coax end to house a small toroid transformer? There's another 1/2-wave kid on the block which is actually a center-fed dipole with the feedline running up the middle of the lower half of the dipole. It's marketed as the Air Whip at http://miracleantenna.com/shop-products/aviation/42 Emacs! The black box houses the common-mode choke which de-couples the feed line from the high-voltage end of the dipole thusly. http://tinyurl.com/78ph8nz http://tinyurl.com/6ul4o6f Waaayyy back when, there was a brief brush with tiny toroids to match coax feedlines to center fed dipoles the cores they used were very low power handling . . . hence good for receive only. The Antenna Dynamics product has the look and 'smell' of a similar product. By the way, the reason it's not 44" (half wave in free space) long is because the lower 1/4 wave is in coax which is shortened to about 14" by the coax velocity factor. Miracle Antenna is a newer kid on the block and gets very good reviews from their whole customer base which includes amateur radio and SWL applications. Dave, is there any chance you can get the remnants of the old antenna out? Putting one of these in it's place would be a prudent move. If that's not practical/possible, then splicing an extension on the upper end to replace the cut off length would be helpful . . . even if it lays off at right angles to the antenna. This would serve as an extension moving back toward 1/4 wave for the upper element and/or 'capacity' hat to load the shortened antenna thus making it look electrically like a quarter wave. Your antenna guy will know all about this and will be able to help you with the patch. Bob . . . ________________________________ Message 15 ____________________________________ Time: 11:35:57 PM PST US From: Dave Saylor Subject: Re: AeroElectric-List: Uneven dipole elements We found a diagram of what we think the antenna looks like. I'll post of a picture of it next week at the latest. It's a slanted-N shape similar to an Archer. Earlier I described equal-length parallel elements. Turns out they're carbon reinforcements that aren't part of the antenna. I'll show them in the picture when I post it. I mistook them as part of the antenna because I was using a "wire sniffer" to find the elements. I had the transmitter attached to the end we'd cut off, and it was making the carbon strips, which aren't connected to the antenna in any way I can see, display to the receiver wand as conductors. Thanks to everyone for all the input. We'll get this figured out. I think if I have to I can add a few perpendicular inches to the shortened end. --Dave Saylor On Fri, Mar 30, 2012 at 9:36 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 06:46 PM 3/30/2012, you wrote: > > noelloveys@yahoo.ca> > > I'm wondering if it is now operating like a modified Windom antenna (not > straight at centre and different length elements). I also would like to > know if it is vertical or horizontal > > > This would be a vertically polarized antenna and > appears to be 1/2 wavelength. Is there enough > 'bulk' at the coax end to house a small toroid > transformer? > > There's another 1/2-wave kid on the block which > is actually a center-fed dipole with the feedline > running up the middle of the lower half of the > dipole. It's marketed as the Air Whip at > > http://miracleantenna.com/shop-products/aviation/42 > > [image: Emacs!] > > The black box houses the common-mode choke which > de-couples the feed line from the high-voltage > end of the dipole thusly. > > http://tinyurl.com/78ph8nz > > http://tinyurl.com/6ul4o6f > > Waaayyy back when, there was a brief brush with > tiny toroids to match coax feedlines to center fed > dipoles the cores they used were very low > power handling . . . hence good for receive only. > > The Antenna Dynamics product has the look and 'smell' > of a similar product. By the way, the reason it's > not 44" (half wave in free space) long is because > the lower 1/4 wave is in coax which is shortened > to about 14" by the coax velocity factor. > > Miracle Antenna is a newer kid on the block > and gets very good reviews from their whole > customer base which includes amateur radio and > SWL applications. > > Dave, is there any chance you can get the remnants > of the old antenna out? Putting one of these > in it's place would be a prudent move. > > If that's not practical/possible, then splicing an > extension on the upper end to replace the cut off > length would be helpful . . . even if it lays off at > right angles to the antenna. This would serve as > an extension moving back toward 1/4 wave for the > upper element and/or 'capacity' hat to load the > shortened antenna thus making it look electrically > like a quarter wave. > > Your antenna guy will know all about this and > will be able to help you with the patch. > > ** > > ** Bob . . . > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.