KR> Antenna Questions/Carbon Fibre/Graphite
Regarding applying copper tape antenna to a carbon fiber shaft or backing. This string made me curious and I spent about an hour trying to educate myself. http://www.antenna-theory.com/ I learned that I am not that curious, but if anone else is, this appears to be a very good resource. Respectfully, Edward Spyker
KR> Antenna Questions/Carbon Fibre/Graphite
I am doing a war replica using my KR plans and need drawings, plans etc to make the landing gear as WAR and/or Loehl do. Does anyone have any plans, sketches and ideas on this? Pat - Original Message - From: "Dana Overall" <bo12...@hotmail.com> To: <kr...@mylist.net> Sent: Wednesday, February 10, 2010 10:11 AM Subject: RE: KR> Antenna Questions/Carbon Fibre/Graphite > > I know there are a lot of roll your own people on the KRNet and all the > best to all you:-), however I used a simple store bought whip antenna and > it worked great. For my VOR I used a wingtip mounted Bob Archer antenna, > see: > http://www.aircraftspruce.com/catalog/avpages/archer_antennas.php It > worked great as I rode many an ILS down using this antenna. Look at Model > 6 on the above page if you want a plug and play version for the com in a > KR. > > Dana Overall > > 1999 & 2000 National KR Gathering host > Richmond, KY i39 > > http://rvflying.tripod.com/blackmagic.jpg > http://www.youtube.com/watch?v=MMi05-WU2D0#GU5U2spHI_4 > http://rvflying.tripod.com > > do not archive > > > > > > _ > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. > http://clk.atdmt.com/GBL/go/201469229/direct/01/ > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html >
KR> Antenna Questions/Carbon Fibre/Graphite
I know there are a lot of roll your own people on the KRNet and all the best to all you:-), however I used a simple store bought whip antenna and it worked great. For my VOR I used a wingtip mounted Bob Archer antenna, see: http://www.aircraftspruce.com/catalog/avpages/archer_antennas.php It worked great as I rode many an ILS down using this antenna. Look at Model 6 on the above page if you want a plug and play version for the com in a KR. Dana Overall 1999 & 2000 National KR Gathering host Richmond, KY i39 http://rvflying.tripod.com/blackmagic.jpg http://www.youtube.com/watch?v=MMi05-WU2D0#GU5U2spHI_4 http://rvflying.tripod.com do not archive _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/201469229/direct/01/
KR> Antenna Questions/Carbon Fibre/Graphite
I'm certainly no antenna expert but I would have a concern about building an antenna in to any part of the aircraft structure. You are betting that you will never have an antenna or connection problem for the life of the aircraft. Fortunately, I was made a gift of the antenna I'm using (http://www.advancedaircraft.com/ and it works GREAT. I'm guessing a builder could build one of similar design and get similar results. My antenna is tie-wrapped to the second cross member behind my baggage bay. It's length is greater than the vertical height available so the top and bottom elements are simply bent in a forward direction when they contact the floor and turtle deck. It passes within 6 inches of my elevator cables. Using this antenna and a cheap hand held radio, I often hear radio chatter 75 miles out, have talked to approach control and tower 35 miles out, and always get a "loud and clear" response. I've communicated with Langford at 50+ miles on several occasions. If I ever have an antenna problem I simply remove the access panel to my turtle deck area, clip two tie wraps, and I have my antenna in hand. Keep it simple and keep on building. Flying is MUCH MORE FUN. :-) Larry Flesner
KR> Antenna Questions/Carbon Fibre/Graphite
After this thrread, I'm tempted to just use smoke signals...LOL -- Glenn Martin
KR> Antenna Questions/Carbon Fibre/Graphite
Well I think the current will be carried on the outside of the tube or copper spiral (faraday effect) just as I seem to remember reading vaguely it is in solid wire???.if so then the conductivity of the internal structure would seem largely irrelevant unless groundedhmmm John Martindale 29 Jane Circuit Toormina NSW 2452 AUSTRALIA ph: 61 2 6658 4767 (H) mob: 0403 432179 email: john_martind...@bigpond.com -Original Message- From: krnet-bounces+john_martindale=bigpond@mylist.net [mailto:krnet-bounces+john_martindale=bigpond@mylist.net] On Behalf Of Glenn Martin Sent: Wednesday, 10 February 2010 3:32 PM To: KRnet Subject: Re: KR> Antenna Questions/Carbon Fibre/Graphite Mark Langford wrote: > just use something else to > stick your copper tape to and get in the air that much quicker... > < I second that motion -- Glenn Martin ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.435 / Virus Database: 271.1.1/2678 - Release Date: 02/09/10 19:35:00
KR> Antenna Questions/Carbon Fibre/Graphite
Mark Langford wrote: > just use something else to > stick your copper tape to and get in the air that much quicker... > < I second that motion -- Glenn Martin
KR> Antenna Questions/Carbon Fibre/Graphite
My thoughts were that the carbon tube would be the exact same length as the copper tape required according to RST. I just thought since everyone says that pretty much only carbon arrows are now available, besides aluminum arrows that if they would work then OK. As I originally thought, on a KR the wooden spar as Mark mentioned would be a safe place for the copper tape antenna. Many composite airplanes copper antennas were laid into a slightly routed, dug, or scraped out trough into the foam of the winglet, tail etc before the initial glass covering was applied. I am now wondering what a guy with an all graphite covered structure would do? besides an external antenna of course. Would he glue the copper tape onto the surface of the graphite frame, then lay-up a layer of light fiberglass cloth? If that will work then the graphite arrow shaft should work. Mark I am in favor of you conducting (no pun intended LOL) the test you mentioned when time permits. Larry Howell From: Mark Langford <n5...@hiwaay.net> To: KRnet <kr...@mylist.net> Sent: Tue, February 9, 2010 8:57:21 PM Subject: Re: KR> Antenna Questions/Carbon Fibre/Graphite I said it was pointless to debate this, but I'm going to debate AGAINST myself. An analogy that makes carbon fiber less than attractive as something to wrap an antenna around is this: If you had a 3' aluminum tube from an old FM antenna and put a layer of shrink tubing around it to insulate, and then stuck the 21.3" copper tape to it for one leg of the dipole, you'd have a reflector that's longer than the element, and that would be Glenn's "extraneous loss". You'd have to cut the aluminum antenna (or carbon fiber shaft as the case may be) to the same length as the copper tape, and even then there MIGHT be problems, so I'm back to what's been mentioned several times already (including me), just use something else to stick your copper tape to and get in the air that much quicker... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Antenna Questions/Carbon Fibre/Graphite
I said it was pointless to debate this, but I'm going to debate AGAINST myself. An analogy that makes carbon fiber less than attractive as something to wrap an antenna around is this: If you had a 3' aluminum tube from an old FM antenna and put a layer of shrink tubing around it to insulate, and then stuck the 21.3" copper tape to it for one leg of the dipole, you'd have a reflector that's longer than the element, and that would be Glenn's "extraneous loss". You'd have to cut the aluminum antenna (or carbon fiber shaft as the case may be) to the same length as the copper tape, and even then there MIGHT be problems, so I'm back to what's been mentioned several times already (including me), just use something else to stick your copper tape to and get in the air that much quicker... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com
KR> Antenna Questions/Carbon Fibre/Graphite
Glenn Martin wrote: >I believe the carbon fiber would do more harm than good,as it ADDS >extraneous loss. < Given the experiment we conducted at work where the conductivity didn't affect EMF, I can't see why Larry's idea of wrapping the copper foil around the arrow shaft lengthwise (down the length of the shaft, not around it) wouldn't be any different from putting it inside a fiberglass shaft. The big difference would be that one has air inside the copper "tube" and the other has a non-conductive but somewhat reflective thing inside. I'll be the first to admit that it's simply a matter of using something else (plastic tubing, a wooden dowel, anything non-conductive) and get on with your life, but it's an interesting test that I'll have to do when things warm up enough to do some outside testing using the same radio but both versions of a dipole antenna. I don't think the copper will care what it's wrapped around the outside of, as long as it's not conductive. But why debate it...I'll test it and we'll know for sure... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com
KR> Antenna Questions/Carbon Fibre/Graphite
Carbon fiber is resistive, thus it would absorb energy and dissipate it in the form of heat. It would likely be a negligible loss, but thats what it would do. In the ARRL Antenna handbook (considered a BIBLE on the subject of antennas) there is NO discussion of making an antenna in this manner, which speaks volumes to me. If you wish to know why VHF and UHF antennas are made of tubing rather than a solid conductor (and you should); learn about "SKIN EFFECT" at UHF and VHF frequencies. In my days at KCRW-FM, the coaxial cable used from the transmitter to the antenna had an inner conductor of 3/4 inch copper tubing, rather than solid wire. The tubing itself needed no further rigidity. The coaxial cable was filled with pressurized nitrogen to keep it dry and non-conductive inside the cable and between the conductors. This also applied to the antenna elements, they too were sealed and pressurized in order to keep extraneous losses to a minimum. I believe the carbon fiber would do more harm than good,as it ADDS extraneous loss. Try a plastic or fiberglass rod instead. Better yet, just use some aluminum parts from an old thrown out TV antenna. If you want a good antenna, MATCH IT to the Transmitter/Feed Line for the best radiation on a field strength meter, or lowest SWR (Standing Wave Ratio) on an inline SWR meter. And as I mentioned before, use a good LOW LOSS Transmission line (see my previous post). Keep it SIMPLE. Glenn Martin N5PQ GROL KR2 N1333A 13238 Hudson-Krohn Rd Biloxi, MS, 39532 rep...@martekmississippi.com
KR> Antenna Questions/Carbon Fibre/Graphite - comment
General comment on the thread: Aren't radio suppressed ignition wires carbon fiber? Conductivity of pure carbon isn't bad, it just needs to be really loaded up to do the deed. The material is used extensively in resistors and varistors. I have used carbon inks and related carbon based materials in the electronics industry for years... they have their place, but maybe not with radios or antennas. Years ago, during a seminar series on Taguchi's methods of design of experiments (that I think he derived from Deming's work), the MSOE instructor running the class opened each one with the statement, "in God we trust, everyone else brings data": does anyone on this forum have data, I'd be interested because I'll be where you are eventually. Thanks! JMHO Mark Wegmet N952MW -Original Message- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Mark Langford Sent: Tuesday, February 09, 2010 5:07 PM To: KRnet Subject: Re: KR> Antenna Questions/Carbon Fibre/Graphite Larry Howell wrote: > If one were to take a graphite arrow rod for example, place copper tape > lengthwise on the arrow shaft, wrap the tape completely around it, attach > appropriate toroids, soldering and wiring to radio of course. Would the > graphite tube in the center, (which we all know is conductive and > reflective) reflect the radio signal in a 360 degree radius, (which is > what we would want) away from the arrow shaft or would it (the shaft) just > screw up the ability of the copper tape to be an antenna?< My guess is that would work fine. We kicked this around at work the other day. I can't say exactly what we were working on, but question of carbon fiber conductivity came up, especially with relation to EMF. We did a lab test where a piece of aluminum was heavily influenced, but a two-layer scrap of carbon fiber layup left over from my KR wings exhibited no such behavior. And resistance was infinite on the surface between any two given points. Sliding the copper foil down into the tube like I did would be problematic though... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Antenna Questions/Carbon Fibre/Graphite
Larry Howell wrote: > If one were to take a graphite arrow rod for example, place copper tape > lengthwise on the arrow shaft, wrap the tape completely around it, attach > appropriate toroids, soldering and wiring to radio of course. Would the > graphite tube in the center, (which we all know is conductive and > reflective) reflect the radio signal in a 360 degree radius, (which is > what we would want) away from the arrow shaft or would it (the shaft) just > screw up the ability of the copper tape to be an antenna?< My guess is that would work fine. We kicked this around at work the other day. I can't say exactly what we were working on, but question of carbon fiber conductivity came up, especially with relation to EMF. We did a lab test where a piece of aluminum was heavily influenced, but a two-layer scrap of carbon fiber layup left over from my KR wings exhibited no such behavior. And resistance was infinite on the surface between any two given points. Sliding the copper foil down into the tube like I did would be problematic though... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com
KR> Antenna Questions/Carbon Fibre/Graphite
Being a ham radio operator, and a practitioner of the dark arts of antenna design, I can't imagine why anyone would wish to bother with complicating something as simple, reliable and effective as a quarter-wave whip or half-wave dipole. Of all of the things you can spend time, energy, effort and money on to improve your experimental aircraft, I think the antenna would be about the last item on my list. While in theory, there are many antennas that will outperform the simple whip or dipole, but in practice the difference is so minimal that it doesn't justify the added complexity. Besides, how much gain does one need? With a simple quarter-wave whip and a hand-held radio, I already have a range of 150 miles or more. Just my 2¢ worth, Lee KN4VN - Original Message - From: "Larry H." <lah...@yahoo.com> To: "KRNET" <kr...@mylist.net> Sent: Tuesday, February 09, 2010 4:46 PM Subject: KR> Antenna Questions/Carbon Fibre/Graphite After the previous questions concerning carbon and fiberglass arrow rods for making com antennas and the mention of carbon fibre/graphite rods I began to think more about it. My first inclination was, of course I wouldn't use carbon but now I would like to have this one question answered. My thinking created only one question in my mind for those who know for sure. If one were to take a graphite arrow rod for example, place copper tape lengthwise on the arrow shaft, wrap the tape completely around it, attach appropriate toroids, soldering and wiring to radio of course. Would the graphite tube in the center, (which we all know is conductive and reflective) reflect the radio signal in a 360 degree radius, (which is what we would want) away from the arrow shaft or would it (the shaft) just screw up the ability of the copper tape to be an antenna? I do know the copper could not come in contact with the graphite, hopefully the resin which makes up the arrow shaft will keep the copper seperated from the graphite fabric. Just wondering? if anyone knows for sure I would like to read your thoughts. Below is the link to RSTs airplane antenna kits which include all the supplies you need to fabricate your own antenna. http://www.rst-engr.com/rst/catalog/airplane_antenna.html Here is a link to the type of antennas a lot of composite aircraft guys used 15 or 20 years ago. I glued one of these in the fiberglass wingtip of my neighbors RV6A many years ago and it worked really well. I think Aircraft Spruce sells these as well. A little pricey compared to making your own from a RST kit. http://www.advancedaircraft.com/ Larry Howell ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Antenna Questions/Carbon Fibre/Graphite
After the previous questions concerning carbon and fiberglass arrow rods for making com antennas and the mention of carbon fibre/graphite rods I began to think more about it. My first inclination was, of course I wouldn't use carbon but now I would like to have this one question answered. My thinking created only one question in my mind for those who know for sure. If one were to take a graphite arrow rod for example, place copper tape lengthwise on the arrow shaft, wrap the tape completely around it, attach appropriate toroids, soldering and wiring to radio of course. Would the graphite tube in the center, (which we all know is conductive and reflective) reflect the radio signal in a 360 degree radius, (which is what we would want) away from the arrow shaft or would it (the shaft) just screw up the ability of the copper tape to be an antenna? I do know the copper could not come in contact with the graphite, hopefully the resin which makes up the arrow shaft will keep the copper seperated from the graphite fabric. Just wondering? if anyone knows for sure I would like to read your thoughts. Below is the link to RSTs airplane antenna kits which include all the supplies you need to fabricate your own antenna. http://www.rst-engr.com/rst/catalog/airplane_antenna.html Here is a link to the type of antennas a lot of composite aircraft guys used 15 or 20 years ago. I glued one of these in the fiberglass wingtip of my neighbors RV6A many years ago and it worked really well. I think Aircraft Spruce sells these as well. A little pricey compared to making your own from a RST kit. http://www.advancedaircraft.com/ Larry Howell
