Date: Fri, 05 Feb 1999 23:53:53 +0000 From: Paul Kuntz Subject: COZY: Antennas in canard I'm about to install two antennas in my Cozy canard, per suggestions in the RST antenna handbook. I plan to put a glide slope antenna on one side of the fuselage and a VOR nav antenna on the other. Each antenna will be under the top skin of the canard, V-shaped with the center of the V near the canard trailing edge and the tips near the leading edge. The legs of the V will angle forward about 15 to 20 degrees, which agrees with RST guidelines. I was originally planning to put the foil strips on the bottom of the canard, but quickly realized that routing the coax down the trailing edge to exit inside the fuselage was going to be tricky while trying to avoid future installation of the high desity foam inserts for the canard hinges, not to mention the hinge pieces themselves. I decided that it would be much easier to put the antennas on the top of the canard before the top skin goes on, and after the high density foam inserts are in place. Then I'll be able to avoid any interference with the hinges. Anyhow, I was wondering how these antennas will perform, since the tips will end up about eight inches away from the elevator torque tubes and hinge pins. The RST rule of thumb for antenna installation is, "no pieces of conductive material longer than one-eighth wave length within one-quarter wave length of the tips of the antenna". My contemplated canard antenna installation will violate this rule most blatantly. I figure these foil antennas are so easy and cheap to install that I'm going to go ahead and try them, but will also install other duplicate antennas in the wings where I am confident of getting decent separation from metal objects. Then I'll see which antennas work best. Has anyone out there tried canard antenna installations? If so, where did you put them and how do they work? Paul Kuntz Cozy MKIV Serial 003 England Date: Fri, 5 Feb 1999 18:22:39 -0600 From: Tom Brusehaver Subject: Re: COZY: Antennas in canard >Anyhow, I was wondering how these antennas will perform, since the tips >will end up about eight inches away from the elevator torque tubes and >hinge pins. The RST rule of thumb for antenna installation is, "no >pieces of conductive material longer than one-eighth wave length within >one-quarter wave length of the tips of the antenna". My contemplated >canard antenna installation will violate this rule most blatantly. I >figure these foil antennas are so easy and cheap to install that I'm >going to go ahead and try them, but will also install other duplicate >antennas in the wings where I am confident of getting decent separation >from metal objects. Then I'll see which antennas work best. My take on this, and this is theory so far, It'll be a couple years before I can tell you for sure, but I have had some experience building antenna, is the nav antenna will perform poorly when the VOR is behind the airplane, and very well when the VOR is ahead of the airplane. The GS antenna will behave the same, but it won't matter, since you only care about GS information when flying towards the signal. I put my antenna (GS and NAV, per RST plans), in the canard also. I put both of them in the leading edge, figuring I didn't want to interrupt the spar cap bond (is that important?), making a really shallow V, but the V only affects the directional abilities of the antenna, so I figured that didn't matter too much. I plan on putting a second NAV antenna in the wing. I have to agree with you. My plan so far is a single VOR/GS/COMM radio, and second IFR capable GPS/COMM radio, leaving the need for two NAV antenna almost non existant. The are so cheap, and easy to hide, it makes sense to put 'em in now, rather than tearing up a finished airplane to put 'em in later (or worse, having all them extra pokey sticks dragging in the breeze). Good Luck. From: Jim Hocut Subject: RE: COZY: Antennas in canard Date: Fri, 5 Feb 1999 21:06:20 -0500 I did some work with antenna simulation software a while ago regarding the glideslope antenna. Turns out a good place to put it is on the leading edge of the canard, on the centerline where it'll be easy to get the coax to your radio. With the torque tube behind the antenna you get a 1 to 2 dB gain in the forward direction. Jim Hocut jhocut@mindspring.com From: cdenk@ix.netcom.com Date: Fri, 5 Feb 1999 20:22:00 -0600 (CST) Subject: Re: COZY: Antennas in canard With near 700 hours on my antennas, I am very happy, I regulary fly IFR everywhere, many times at minimum reception altitudes: 1: All of my antennas are Antenna Dynamics, mylar plated like a printed circuit board. The Vor antennas have a Balun at their centers in a 1" cube box with a BNC coax connector. The glideslope is fed from a splitter box mounted near the radios. 2 VOR antennas in the canard are in the bottom about midway forward of the sparcap and the leading edge. The coax is in a routed groove on the top side microed in and emerge the top near the center, and then in the filler foam on to the canard, exiting the aft face of the filler just above the elevator tube, and clear of the bellcrank. 3: Don't put a special antenna in for glideslope, it works fine with a splitter (at least with my antennas), instead put 2 VOR antennas in. Then if one fails, just get another splitter with 2 VOR's and glideslope. 4: The marker beacon is bottom fuselage on one side 5: the ADF is under my thigh support, fully above the floor bottom. 6: The 2 Com antennas are in the fin outside surfaces. 7: The transponder is a small exterior fin under passenger seat. THinking of replacing it with a foil antenna between the wing and strake. They weren't available when I built. I could scan photos of most of these, make *.JPG files and attach to mail on request. From: cdenk@ix.netcom.com Date: Fri, 5 Feb 1999 20:46:16 -0600 (CST) Subject: RE: COZY: Antennas in canard was wrote:<1 to 2 dB gain in the forward direction.> > What happens when you are perpendicular to the runway centerline, just flew through it, some distance out? or flying procedure turn outbound with the transmitter behind you? Date: Sat, 6 Feb 1999 13:00:01 -0600 From: Tom Brusehaver Subject: Re: COZY: Antennas in canard >was wrote:<1 to 2 dB gain in the forward direction.> >> >What happens when you are perpendicular to the runway centerline, >just flew through it, some distance out? or flying procedure turn >outbound with the transmitter behind you? The model he used was for GS, not VOR. Yup, the VOR antenna might not work very well in this situation, but 1-2db loss (big maybe, assuming symetry) would reduce your range maybe to half, so it should still work 5-20miles out, depending on altitude. You normally only care about the GS when flying towards the runway, they aren't at all accurate when perpendicular to the runway at all. Think of where the VOR antenna are on like a metal plane (top of the tail). How do they work on an approach, trying to read a signal through the metal wings? (I know they are more than 1/4wave away, but I'll bet there could be a >1db signal loss). From: cdenk@ix.netcom.com Date: Sat, 6 Feb 1999 13:22:23 -0600 (CST) Subject: Re: COZY: Antennas in canard Was said If you are at the marker outbound (for procedure turn)altitude at the same as inbound altitude, thats where you normally intercept the glideslope inbound, and its your first verification of altimeter and glideslope From: Jim Hocut Subject: RE: COZY: Antennas in canard Date: Sat, 6 Feb 1999 16:25:40 -0500 1 to 2 dB is not a lot of gain for a directional antenna. I would hesitate to even call it directional with that small amount of gain. If you feel strongly that you want to have glide slope reception when flying perpindicular to the runway extended centerline then you could make the glideslope antenna in an elongated V shape, with the center of the V on the canard leading edge at the centerline and the ends of the V on the upper surface of the canard maybe 3 or 4 inches back from the leading edge. Jim Hocut jhocut@mindspring.com Date: Sat, 06 Feb 1999 11:42:11 From: "Robert L. Nuckolls, III" Subject: RE: COZY: Antennas in canard At 08:46 PM 2/5/99 -0600, you wrote: >was wrote:<1 to 2 dB gain in the forward direction.> >> >What happens when you are perpendicular to the runway centerline, just flew through it, some >distance out? or flying procedure turn outbound with the transmitter behind you? The ideal dipole antenna (feedline runs at right angles to antenna for several wavelenghts - 10 feet or more, nothing conductive within 10 wavelengths) will show a sharp null when the received signal is right off the end of the antenna. I practice, this null is distorted and not very deep due to proximity of other conductive materials on the aircraft. Further, ILS signals off the end of the runway are huge . . . a wet string will work for an LOC/GS antenna for most modern receivers. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < A mind abhors a vacuum . . . > < When deprived of facts, > < our fantasies are generally > < much worse than reality. > ================================= From: Wayne Hicks Subject: COZY: Coax Splitters Date: Mon, 8 Feb 1999 08:32:20 -0500 Typical NAV VOR installations use a splitter to connect one NAV antenna to two NAV radios. But what about the glideslope (GS)? I've never seen the business end of radios, so I'm not familiar with how the antennas are connected back there. My FBO guy says to use splitters and feed all NAV radios, including GS, from a single antenna. Barring the redundancy issue (I will install redundant antennas), some questions: 1. Can a NAV antenna be split to provide signal for the GS? Pros and cons? 2. If so, what is the splitter arrangement (e.g., (a) split the antenna feed onto two lines, then split one of those into two more, or (B) split into three lines)? 3. If #1 is true and my FBO guy are correct, then why is the GS antenna shorter length (ref: RST booklet) than the NAV? 4. Is there anything to be gained (pun intended) by feeding the GS with its own GS antenna? Right now, I've got a NAV antenna in the belly. I'm leaning toward putting NAV #2 and a GS in the canard. Thoughts and comments? PS--> Thanks to the archives, I have a better understanding of the installation logistics in the canard. ____________________________________________________ L. Wayne Hicks SpaceTec Division, Zel Technologies, LLC Sr. Engineer 3221 North Armistead Ave 757-865-0900 phone Hampton, VA 23666 757-865-8960 fax http://www.spacetec-inc.com http://www.zeltech.com Date: Mon, 08 Feb 1999 13:57:24 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Coax Splitters At 08:32 AM 2/8/99 -0500, you wrote: > >Typical NAV VOR installations use a splitter to connect one NAV antenna to >two NAV radios. But what about the glideslope (GS)? I've never seen the >business end of radios, so I'm not familiar with how the antennas are >connected back there. My FBO guy says to use splitters and feed all NAV >radios, including GS, from a single antenna. Barring the redundancy issue >(I will install redundant antennas), some questions: > >1. Can a NAV antenna be split to provide signal for the GS? Pros and cons? > >2. If so, what is the splitter arrangement (e.g., (a) split the antenna >feed onto two lines, then split one of those into two more, or (B) split >into three lines)? >3. If #1 is true and my FBO guy are correct, then why is the GS antenna >shorter length (ref: RST booklet) than the NAV? You can hook 2 navs and a GS to a single nav antenna but it's not a free lunch. GS frequencies are approx 3x LOC/VOR frequencies. There are ramifications in the physics that mak nav antennas good performers for GS use. Splitters are available for 2 VOR/LOC receivers to share an antenna and others for 1 VOR/LOC and 1 GS to share the antenna . . . they may be very different inside and not interchangeable. The splitters are not perfect devices and therefore degrade receiver performance a tiny amount. LOC/GS signals are very strong (only 10 miles max from end of runway) so a single antenna feeding two VOR receivers may expect some degredation . . . probably too small to be significant. Given the very strong signals in the ILS mode and the fact that your airplane is plastic, consider attaching a 10" piece of wire to a connector that mates with the coax fitting on your GS receiver and just plugging it in. Dress the end of the wire away from other wires (perhaps tape it to structure?). This would reduce your parts count in the nav antenna line (increase reliablilty) and reduce losses to one of the VOR receivers for having inserted a second coupler. >4. Is there anything to be gained (pun intended) by feeding the GS with its >own GS antenna? Lost you here . . . >Right now, I've got a NAV antenna in the belly. I'm leaning toward putting >NAV #2 and a GS in the canard. Great . . . now plug the wire into the GS receiver and you have eliminated a single point of failure for all three receivers. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Go ahead, make my day . . . > < show me where I'm wrong. > ================================= From: cdenk@ix.netcom.com Date: Mon, 8 Feb 1999 16:46:00 -0600 (CST) Subject: Re: COZY: Coax Splitters feed all NAV >radios, including GS, from a single antenna? Yes they can all be fed from 1 antenna, the splitter is about $60. The same situation as feeding several TV sets from one antenna. Each time you split the signal, the signal gets slightly weaker. The issue is can you live with the weaker signal. Probably, depends on how good the antenna is at collecting the signal. GS antenna shorter length? Can't tell you why, but it works. Just not as efficient. feeding the GS with its own GS antenna? Stronger signal, maybe not needed. >NAV #2 and a GS in the canard. Put both Nav in the canard, short cables to the radios, probably the shorter wire offsets the loss of the splitter for the glideslope. I can't say I notice any difference between my VOR's as far as receiving distant stations, one with one without the splitter. Date: Mon, 8 Feb 1999 17:57:49 -0600 From: Tom Brusehaver Subject: Re: COZY: Coax Splitters >GS antenna shorter length? >Can't tell you why, but it works. Just not as efficient. The glideslope antenna is shorter than a nav antenna because the GS is at a higher frequency. (more HZ, less wiggle, shorter ANT) Date: Tue, 09 Feb 1999 16:03:52 From: "Robert L. Nuckolls, III" Subject: Re: COZY: Re: Coax Splitters At 10:03 AM 2/9/99 -0800, you wrote: >What kind of marker antenna would work in a Cozy? >Marc > Another good instance where the plastic airplane makes life easier. I'd hook a 40" piece of wire to the receiver's connector and just string it out in as straight a line as possible away from the receiver and other conductive things. MB signals are from a 5 watt transmitter a few hundred feed beneath you with a directional antenna pointing straight up . . . the signal is HUGE . . . a wet string antenna would work. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Go ahead, make my day . . . > < show me where I'm wrong. > ================================= From: cdenk@ix.netcom.com Date: Tue, 23 Mar 1999 20:50:11 -0600 (CST) Subject: Re: COZY: GPS Antenna Placement On 03/23/99 19:32:41 you wrote: > >What is the collective wisdom on GPS antenna placement? I have a KLX 135A >(shared with my Cessna 120!). > >Any advice is welcome. > >Will > > > GPs's aren't fussy, except they do not want to be shadowed from the satelites by anything metallic. This means a high point of the airframe. Mine on a Cosy is recessed about 1/4" on the top of the canopy about 6" aft of the plexiglass bubble. I have a conductive fiberglass ground plane 6" diameter, but thats probably not required, remember that installation was 7 years ago, when there wasn't much experience. Many have had fiberglass structure above the antenna without any problems. From: "Will Chorley" Subject: COZY: More ELT Antenna Mounting questions Date: Tue, 20 Apr 1999 20:57:49 -0500 On reading the installation instructions for the AK-450 ELT, they say the antenna needs a 36" diam. ground plane. This seems to be a bit tricky to provide anywhere in the plane unless you mount the antenna in the middle of the passenger compartment. I would like to follow some others and mount the antenna behind the front seat bulkhead, but what about this ground plane business? Suggestions would be welcome and maybe some of the radio gurus out there could let us know what degradation in performance we could expect without a significant ground plane. Will a satellite still pick up the signal for instance? Thanks in anticipation of any useful hints, tips, and information, Will From: cdenk@ix.netcom.com Date: Wed, 21 Apr 1999 17:10:38 -0500 (CDT) Subject: Re: COZY: More ELT Antenna Mounting questions I don't have a ground plane, the antenna projects into the pilot's headrest. I can assure you my installation has been notorious several times, when the ELT has went off while the plane was on the ground. This with an ACK ELT. It convienient to get the D batteries at Walmart or small town hardware store. From: "John Slade" Subject: COZY: Marker Beacon Antenna Date: Sat, 24 Apr 1999 17:21:40 -0400 Hello all, >From all mentions I can find in the archives I see that a MB antenna should be "about" 78 inches tip to tip. In the RST manual (drawing 802-8905) they say the length of each strip should be 34.3inches. In the text they refer to 78inches. Which is correct, where does the 10 inch difference go, or doesn't it matter? Thanks for any input. John Slade #757 (glassing my bottom tomorrow!) PS I just bury the soldered contacts and donuts in the foam and fill the hole with micro, right? Date: Sun, 25 Apr 1999 00:38:17 -0400 From: "Marc J. Zeitlin" Subject: Fwd: COZY: Marker Beacon Antenna John Slade wrote; >>From all mentions I can find in the archives I see that a MB antenna should >be "about" 78 inches tip to tip. In the RST manual (drawing 802-8905) they >say the length of each strip should be 34.3inches. In the text they refer to >78inches. >Which is correct, where does the 10 inch difference go, or doesn't it >matter? I have all the RST literature, and I could find 4 references to 34.3 inches, and none to 78 inches. I also found one reference to the MB antenna being just UNDER 6 feet long. I'm guessing that if it says 78 inches somewhere, it's a typo. Use the formula Jim Weir gives and calculate the length yourself. 2578 L = ----- f Where L is the arm length, and "f" is the frequency in MHz. MB use 75 MHz, so we get 34.37" arm length. Voila. >PS I just bury the soldered contacts and donuts in the foam and fill the >hole with micro, right? Yep. Baluns though, not donuts. Donuts (at least the ones from Dunkin) don't have the right electrical characteristics :-). -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ From: "John Slade" Subject: Re: COZY: Marker Beacon Antenna Date: Sun, 25 Apr 1999 09:45:40 -0400 >I have all the RST literature, and I could find 4 references to 34.3 >inches, and none to 78 inches. I also found one reference to the MB >antenna being just UNDER 6 feet long. I'm guessing that if it says 78 >inches somewhere, it's a typo. Use the formula Jim Weir gives and >calculate the length yourself. > > 2578 > L = ----- > f > >Where L is the arm length, and "f" is the frequency in MHz. MB use 75 MHz, >so we get 34.37" arm length. Voila. Now I'm even more confused. Page 7 of my RST-802 reference text gives the formula for wavelength as 11800/f, then divide by 4, or 2950/f. Both give me a len of 39.33. Where did you get the 2578 figure? >Donuts (at least the ones from Dunkin) >don't have the right electrical characteristics :-). some of them are close! :> John Slade Date: Sun, 25 Apr 1999 11:08:14 -0400 From: "Marc J. Zeitlin" Subject: Fwd: Re: COZY: Marker Beacon Antenna John Slade forces me to actually understand what I wrote: >Now I'm even more confused. Page 7 of my RST-802 reference >text gives the formula for wavelength as 11800/f, then divide by 4, or >2950/f. Both give me a len of 39.33. Where did you get the 2578 figure? OK, here's what I can figure out (I'm not an electrical engineer, nor do I play one on TV). The 2578 L = ---- f Is for the length of each leg of a DIPOLE antenna - i.e. the kind we make with the copper tape and baluns. The 2953 L = ----- f is for a QUARTER WAVE antenna, such as the transponder antenna RST describes. So, for the copper tape NAV, COM, MB, and GS antenna, use the first formula. For a DME or transponder antenna, use the second. That's as much as I can figure out. I haven't a clue as to the derivation of these numbers :-(. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ From: "John Slade" Subject: Re: Re: COZY: Marker Beacon Antenna Date: Sun, 25 Apr 1999 13:05:31 -0400 >John Slade forces me to actually understand what I wrote: :) No, Marc. I don't think that's right. We divide 11800 by four because were making a 1/4 wave antenna. IN his example he refers to a com antenna and uses the 2950 figure. I think the diverence is something to do with the width of the copper tape. Jim says that the correct length "will always be at least 5% less" than the calculated length using 2950. He also says there's no rule of thumb for this. Where did you see 2578? I sent email to Jim Weir for clarification. If I get some I'll post the info. >From the archives I suspect that there are a lot of 78inch MB antenna out there, probably all working just fine. Thanks for the input. John Date: Sun, 25 Apr 1999 18:51:33 -0400 From: "Marc J. Zeitlin" Subject: Re: Re: COZY: Marker Beacon Antenna John Slade wrote; >Where did you see 2578? Page 58 and 60, January 1981 Sport Aviation article reprint - I think it's available on RST's web page. This is the formula he uses for the COM and NAV antennae also. I don't know WHY the formula for a dipole antenna is different than for a 1/4 wave "whip" antenna, but apparently it is (or at least it was 17 years ago according to Jim Weir). >I sent email to Jim Weir for clarification. If I get some I'll post the >info. Good - I'm sure he'll be able to explain what's up here. >>From the archives I suspect that there are a lot of 78inch MB antenna out >there, probably all working just fine. Could be..... -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ Date: Mon, 26 Apr 1999 13:00:51 From: "Robert L. Nuckolls, III" Subject: Re: Re: COZY: Marker Beacon Antenna At 06:51 PM 4/25/99 -0400, you wrote: >John Slade wrote; > >>Where did you see 2578? > >Page 58 and 60, January 1981 Sport Aviation article reprint - I think it's >available on RST's web page. This is the formula he uses for the COM and >NAV antennae also. I don't know WHY the formula for a dipole antenna is >different than for a 1/4 wave "whip" antenna, but apparently it is (or at >least it was 17 years ago according to Jim Weir). > The "whip" antenna is 1/4 wavelength and has to work against a ground plane (metal skin or spider of conductors on a plastic airplane). The dipole is 1/2 wavelength and requires no ground but is 2 times as long. For composite airplanes, the marker beacon signal is so strong (it's just a few hundred feet below you) that you can stick a 40" piece of 22AWG wire into a BNC connector and plug it into the receiver. Route the wire away from the receiver in as much "clear" area as you can manage keeping the wire as straight as possible (which generally isn't very possible). Tape or otherwise secure it to non conducting structure of the airplane. I think you'll find that it works well. The 75 MHz marker beacon transmitters are about 5 watts output into a directional antenna that points straight up from the site . . . the cone of the signal is pretty small for obvious reasons but it's quite strong inside the cone . . . a wet string will pick it up. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Wed, 07 Jul 1999 10:18:15 -0400 From: bil kleb Subject: COZY: denk's antenna installations carl threw some photos of his antenna installation at me in february. we put them online, but we never made an announcement or a link to the page. so this is a note to say, have at yet another collection of photos: http://www.geocities.com/~kleb/homebuilt/other.html -- bil Date: Sun, 22 Aug 1999 10:47:05 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Antenna Groundplane >With all the recent discussion about antenna efficency and interference from other sources I have a question on my groundplane for the transponder antenna. It is .016 alum x 18" dia and is located under the LH seat pan and trapped by the cage/shell bolts. Should it be insulated from the cage or does it not matter? Presently the bolts make it elect bonded to the cage. I'm curious about the 18" diameter . . . it's not optimum for a dedicated ground plane. On plastic aircraft, the ground plane should have a RADIUS equal to the seated height of the antenna. In the case of transponder antennas, this would be 2.6" which translates to 5.2" in diameter. The rational for an optomized ground plane is that it takes place of what might otherwise be a relatively large expanse of aluminum skin found on the heavy-iron. By making it physically matched to the operating frequency of the antenna, performance is optomized. Having said that, would I recommend any changes to the system you've described? . . . . No. If one were to set off at a distance with a signal strength measuring device and compare your installation with an optomized installation and an identical installation on an all metal airplane, the differences would be very hard to measure. The concept of an optomized ground plane provides a minimum size for a system not yet installed. It's not worth your trouble to tear out and replace what you already have. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurasic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Fri, 03 Sep 1999 20:14:13 -0400 From: Gregg Perry Subject: COZY: Re: [c-a] Com/Vor Antena Dave Black wrote: > Here's the problem: > The COMM antenna must be vertical, while the NAV antenna must be > horizontal. Interesting! So what do we do if we want to connect one of the new handheld navcomms to an external antenna to use as an emergency backup for BOTH navigating and communicating? The new Yaesu has only one antenna connection. Gregg Perry Date: Sat, 04 Sep 1999 05:22:21 -0400 From: Dave Black Subject: COZY: Re: [c-a] Com/Vor Antena Gregg, >> The COMM antenna must be vertical, while the NAV antenna must be >> horizontal. > Interesting! So what do we do if we want to connect one of the new handheld > navcomms to an external antenna to use as an emergency backup for BOTH navigating > and communicating? The new Yaesu has only one antenna connection. The proper solution is two antennas and a switch. However, if you're determined to do it with one antenna and are willing to settle for some loss of signal strength on both NAV and COMM, you could mount a single antenna on a 45° angle. This is effectively what you get if you mount one element of the antenna on a vertical surface and one element on a horizontal surface as John Rippengal suggests. With this setup, you'd probably pick up NAV signals fore and aft, but have increasing difficulty as they approached 3 o'clock and 9 o'clock. I'd recommend separate antennas if at all possible. Dave Black Velocity RG Date: Sat, 04 Sep 1999 11:37:02 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: [c-a] Com/Vor Antena >>> The COMM antenna must be vertical, while the NAV antenna must be >>> horizontal. > >> Interesting! So what do we do if we want to connect one of the new handheld >> navcomms to an external antenna to use as an emergency backup for BOTH navigating >> and communicating? The new Yaesu has only one antenna connection. > > >The proper solution is two antennas and a switch. > >However, if you're determined to do it with one antenna and are willing to >settle for some loss of signal strength on both NAV and COMM, you could mount >a single antenna on a 45° angle. This is effectively what you get if you mount >one element of the antenna on a vertical surface and one element on a >horizontal surface as John Rippengal suggests. With this setup, you'd probably >pick up NAV signals fore and aft, but have increasing difficulty as they >approached 3 o'clock and 9 o'clock. > >I'd recommend separate antennas if at all possible. While it is true that a vertical comm and horizontal VOR antenna represent optimum performance, you would he hard pressed to "see" it without test equipment. The hand-held VOR/Comm transceivers will work quite satisfactorily on the Comm antenna. Given the limited power output of your hand held comm transmitter and the VERY HEALTHY vor signal strength at cruise altitudes, I'd give weight to the communications performance and use the Comm antenna on your hand held. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sun, 05 Sep 1999 11:54:53 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Antennas At 05:03 PM 9/4/99 -0200, you wrote: > >Bob, > >Fred Hulen here, off the net. I have purchased one of your manuals, so >maybe you wouldn't mine answering a quick question for me. My plesure sir . . . >I am ready to mount a Comant CI-292-2 (BOTTOM MOUNT type, steeply swept >back Com antenna) on my Zenith 601. I see in the archives that most 601 >builders mount their transponder antenna immediately behind the rear "Z" of >the center wing section (I must assume you are not familiar with the 601, >so the rear Z is the last structural member going from left to right at the >very rear of the center wing section where it attaches to the rear >fuselage.) Anyway... my questions is this: Due to limitations in ground >clearance there is a limit as to how far I can mount the Com antenna toward >the rear away from the transponder antenna, and, in trying to stiffen the >mounting area for the com antenna near on of the "L" crossmembers, the >forward base of the com antenna will be about 23" away from the transponder >antenna. Is this OK? Otherwise I'll have to find a different location for >the transponder antenna. The risk for mounting them closer together is that the transponder transmitter will put little buzzes into the comm receiver every time it replies to a radar interrogation. I would suggest this: Go ahead and mount the comm antenna further forward and see how well it works. If the transponder's interferrence with the comm receiver is small (meaning tollerable) or non-existant, then you're off and running. The worst thing that happens is that you have to find a new, more remote location for the transponder antenna later which is no worse than you are considering right now. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Sat, 11 Sep 1999 12:54:27 -0500 From: "Robert L. Nuckolls, III" Subject: COZY: Re: Coax Cable At 02:39 PM 9/10/99 +0000, you wrote: >Can you tell me the difference between RG142 and RG400 >cable except that one has solid center conductor and the >other stranded. Their electrical performance seems to >be the same, and their physical dimensions also seem >equivalent but I was wondering if the RG400 might be >more flexible and have a smaller bend radius. That >might be an advantage when threading through the >airframe, but it might have other disadvatages! Since >both cables are fairly pricy, I don't want to buy the >wrong cable! > >Thanks again for you helpful advice, > >Will Chorley > >PS. Do you sell the fiberglass isulation material for >fuseable link construction, it doesn't seem to be listed >on your Web pages? Why use either of these cables? The good ol' RG-58 has been used with great success for about a half century. The reason the BIG guys (al la 747, DC-10 etc) use this kind of cable is that their coax runs can be quite long . . sometimes. In a single engine a/c the longest run is generally to a VOR antenna on tail (perhaps 20'). Losses in RG-58 at 110 MHz are about 1.2 dB per 100' (3db is loss of 1/2 the power). A 10' chunk of RG-58 looses .12 dB and a 20' chunk is .24 dB . . . not worth worrying about. Transponders at 1000 mHz will loose 18-22 dB per 100 feet or 2.2 dB for 10' and 1.1 dB for 5 foot. Here, it's obviously more critical but even when you go to a twice diameter, lower loss coax like RG-8 or RG-214, the looses only go down by about half. The modern RG cables like 400 and 142 are still small diameter cables and have losses comparable to RG-58. They ARE made from Teflons, et. als. which increases their resistance to temperature effects but give the very long history of RG-58 and RG-8 in airplanes, I'd suggest that the time and effort to upgrade your small airplane's coax cables isn't going to produce any perceivable value in return. Another thing to consider for bigger cables are connectors. The larger (.35 to .4" diameter) cables take special connectors. I've seen a number of installations where a builder used straight coax connectors on his fat coax than added right angle adapters at each end for installation. The losses in the adapters may have increased his total system losses by as much as he saved by not using smaller RG-58 with the proper right angle connectors. Bottom line is that much is said and recommended with respect to "modernizing" one's anteanna feedlines in amateur built airplanes. My recommendation is to save the time and dollars for things that will make a difference. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com From: anneandwill@att.net Subject: COZY: More Antennae questions Date: Wed, 15 Sep 1999 19:13:17 +0000 I'm just about to glue the top onto the nose of my bird but before I do I thought I'd get some antennea sorted out. (It's much easier to work inside when the top's open!) My thoughts, on which I would like to hear your considered opinion: Mount an AAE Plastic NAV antenna up against the nose bulkhead and bent back against the sides (I DID put a foil NAV Antenna in the belly, carefuly avoiding the brake, but right in line for the landing light!). Stick a transponder antenna through the floor somewhere in front of the co-pilot's feet using a 6" dia ground plane, and make a bracket to mount a GPS antenna off center under the forward access hole so you can still reach into the front compartment to get at the landing gear, etc. What do the antennae gurus think about his arrangement - I like it 'cause it keeps the cables short. Thanks, as always, for your help, Will From: cdenk@ix.netcom.com Date: Wed, 15 Sep 1999 16:06:21 -0500 (CDT) Subject: Re: COZY: More Antennae questions I have 2 VOR/ILS with coupler for GS mounted straight on the bottom of the canard. From: "Nat Puffer" Subject: Re: COZY: More Antennae questions Date: Wed, 15 Sep 1999 13:39:04 -0500 Builders, The transponder antenna works well with the probe protruding through the floor of the nose forward of the rudder pedals. The GPS antenna works well mounted just under the access door in the nose. If the access door is a foam sandwich, remove all but the top skin over the antenna to get it up as high as possible. I don't know what an AAE plastic nav antenna is, but you can make your own for about 50 cents and mount it on the underside of the canard, with the tips of the v forward. This keeps the antennas apart as well as minimizing the length of the coax cables (and also keeps your bird light). The com antennas have to be oriented vertically, so the winglets is the best place for them. I have installed these antennas in a number of airplanes and they all have worked much better than factory antennas (I make them per Jim Weir). Best regards, Nat From ???@??? Mon Oct 11 09:04:21 1999 Return-Path: owner-cozy_builders@betaweb.com Received: from twc2.betaweb.com (majordomo@betaweb.com [206.43.209.18]) by acestes-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with ESMTP id CAA03534 for ; Mon, 11 Oct 1999 02:44:01 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id CAA04496 for cozy_builders-list; Mon, 11 Oct 1999 02:13:17 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from smtp.storkgroup.com ([212.1.18.99]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id CAA04478 for ; Mon, 11 Oct 1999 02:13:05 -0400 Received: from md63157.fae.storkgroup.com ([145.73.181.201]) by nlsr001ppnoc.fae.storkgroup.com (Lotus Domino Build v50.a_1) with SMTP id 1999101108113147:975 ; Mon, 11 Oct 1999 08:11:31 +0200 From: "wydo van de waerdt" To: Subject: COZY: Pre-build : What antanae to put in first. Date: Mon, 11 Oct 1999 08:11:51 +0200 MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2314.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-MIMETrack: Itemize by SMTP Server on nlsr001ppnoc/Server/StorkGroup(Release 5.0a (Intl)|4 May 1999) at 10/11/99 08:11:31 AM, Serialize by Router on smtp/Server/StorkGroupSMTP(Release 5.0a (Intl)|4 May 1999) at 10/11/99 08:07:23 AM, Serialize complete at 10/11/99 08:07:23 AM Message-ID: <011d01bf13af$82a63b40$c9b54991@fae.storkgroup.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="iso-8859-1" Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: "wydo van de waerdt" X-UIDL: f80e62b941d934a6e1401844fa841529 Hi builders, I am planning my material order. I need to know what antennae to order. I would like to make them myself or buy them cheap ( I am Dutch you know !!) Suppose the cozy will be fully IFR, with all the fancy stuff you can think off. I am not an expert an avionics you already guessed. So talk to my as in the book " avionics for dummy's" (Don't ask were to buy this book, I think it doesn't exists) What will I need to buy so I will have know surprises latter on in the project. Thanks in advance. Regards, Wydo van de Waerdt (NL) #???? Pre-build From: "John Slade" Subject: Re: COZY: Pre-build : What antanae to put in first. Date: Mon, 11 Oct 1999 09:14:03 -0400 Guten morgan Wydo, >I need to know what antennae to order. I'd recommend getting the antenna kit from RST. See my web page at http://www.kgarden.com/cozy/chap22.htm for more info. The kit includes all you need to build most antenna, plus detailed instructions. Cost about $30 or so. You might also find their intercom kit interesting. >So talk to my as in the book " avionics for dummy's" >(Don't ask were to buy this book, I think it doesn't exists) The RST booklet comes close with respect to antenna. You might also consider Bob Nuckolls's book on aviation electrical systems. (also linked to my Chap 22 page). Regards, John Slade Cozy MkIV #757 Date: Mon, 22 Nov 1999 09:09:42 -0600 From: "Robert L. Nuckolls, III" Subject: COZY: Re: antenna >> What is the latest thoughts on using the foil dipole antenna from S-H? >> I already have it and want to use it. Also what is the best choice for >> other antenna locations? Nav, transponder, marker beacon, elt? There >> are more 'Star's out there flying now so we should have some definitive >> answers from real world experiences. All help would be appreciated since >> I am bonding the fuselage and this is an integral part of the job if you >> want ot conceal the antenna. Real world perspectives on amateur built antenna installations run the gamut from (a) doesn't work worth a @#$@#! to (b) works really fine! Never have I seen engineering test data to compare a new antenna with an old one. Go ahead and install any and all antennas you might like to try. If they're inside, there's little harm done if you decide your experiment falls into the !@#$@#$! category. At the worst, you'll replace them with time honored whiskers sticking out everywhere. Odds are in your favor that they WILL perform adequately to you task. Bob . . . //// (o o) ===========o00o=(_)=o00o========= < Independence Kansas: the > < Jurassic Park of aviation. > < Your source for brand new > < 40 year old airplanes. > ================================= http://www.aeroelectric.com Date: Tue, 23 Nov 1999 11:34:53 -0600 From: David Domeier Subject: Re: COZY: Re: antenna Bob, re "Real world perspectives on amateur built antenna installations run the gamut from (a) doesn't work worth a @#$@#! to (b) works really fine!" Put me in both categories. With the RST antenna in the winglets things are just fine unless I am in a corridor NW and SE of our local tower. One spot is at the end of the east runway and the other is at an intersection on the other runway. Reception in those areas is very poor, like much static and barely readable. If I move several hundred feet, everything works fine. I've noticed it in the air also. What's causing that? dd From: "Nat Puffer" Subject: COZY: antennas Date: Wed, 1 Dec 1999 11:30:34 -0600 Builders, Jim Weir, at RST, is and expert on homemade antennas to save mucho $. We have used all of his antennas in 4 airplanes over 21 years, and can attest to the fact that there are no better antennas anywhere, regardless of how much you spend. He will tell you that the bandwidth of a com antenna is related to the diameter. It would follow, therefore, if you are in such a position that your homemade antenna is presenting only about .010" width to the tower, reception and transmission might not be 100%. the cure is simple however, just turn your airplane a bit. We have the transponder antenna in the nose, and if, as sometimes happens, the center tells us they have lost us on radar, I just tell them I will make a turn, and sure enough, they pick us up again. Regards, Nat From: "wydo van de waerdt" Subject: COZY: chap 20 question: Coax cable in winglet Date: Wed, 1 Dec 1999 08:06:51 +0100 Dear Cozy builders, I was planning the RST antennae kit. 1) What length of RG58 AU Coax cable do I need to order ?? 2)Can I make some kind of coupling in my wingtip near the strobe assy, routing it 1 ft in the wingtip so I can pull it out ? Or should I make the coupling in the fuselage ? 3) Why not installing the antennae's on both sides of each winglet? (this should be a ones in a live time installation) 4) Why not installing the antennae's on both sides of each wing? (this should be a ones in a live time installation) 5) Has somebody documented his antennae installation in detail (pictures & dimensions), or is the RST manual sufficient. Asking these stupid questions you know I am not a professional on this subject. Regards, Wydo van de Waerdt (NL) #827 From: "John Slade" Subject: Re: COZY: chap 20 question: Coax cable in winglet Date: Fri, 3 Dec 1999 19:25:29 -0500 Marc, >The transponder antenna is in the nose, as will be the GPS >antenna. All of those cost about $20 total. What did you use for a transponder antenna? I didnt see anything about these in the RST manual. Regards, John Slade Date: Fri, 03 Dec 1999 18:50:46 -0500 From: "Marc J. Zeitlin" Subject: COZY: chap 20 question: Coax cable in winglet Wydo Van De Waert wrote; >1) What length of RG58 AU Coax cable do I need to order ?? Get a 100 ft. roll. You'll use most of it, and it's cheaper that way. >2)Can I make some kind of coupling in my wingtip near the strobe assy, >routing it 1 ft in the wingtip so I can pull it out ? >Or should I make the coupling in the fuselage ? I put a coupling at the wing root near the end of the strake. >3) Why not installing the antennae's on both sides of each winglet? (this >should be a ones in a live time installation) You put a COMM antenna in each winglet - two COMM antennae are enough, I think. You could put in more, but that's a LOT of wire :-). >5) Has somebody documented his antennae installation in detail (pictures & >dimensions), or is the RST manual sufficient. The RST manual is completely sufficient. I've got a NAV antenna in the bottom of the fuselage, another one in one wing skin, two COMM antennae in the winglets, a marker beacon antenna in the canard, and a glideslope in the other wing. The transponder antenna is in the nose, as will be the GPS antenna. All of those cost about $20 total. I'm sure I'll never use more than one Comm, the transponder and the GPS. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ Date: Fri, 03 Dec 1999 21:45:56 -0500 From: "Marc J. Zeitlin" Subject: COZY: chap 20 question: Coax cable in winglet John Slade asks; >What did you use for a transponder antenna? I didnt see anything about these >in the RST manual. In one of Jim Weir's articles (available on the RST web pages, I think) there's a description of a transponder antenna. Basically, it's a 5.25" (about) diameter metal disc (I used 1/16" aluminum) with a stub mounted in the middle. Don't remember the length of the stub, OTTOMH (off the top of my head). Put a BNC connector on the end, and voila' - a transponder antenna. I bought the stub from ACS - maybe it was $12 or so and came with the BNC on it. You could make one in 1/2 hour out of "stuff" and a BNC connector, probably. >From our own web page archives (in one of the "antennae" files): http://www.rst-engr.com/ Also, check those archives - there have been innumerable (that's more than 7 for us engineers) discussions of antennae. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/