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Antenna Musings....

Ironflight

VAF Moderator / Line Boy
Mentor
I am planning on doing some antenna upgrades, and thought maybe a little discussion here might smoke out some new ideas from folks, so here goes:

When I built the Valkyrie, I installed a good, solid RAMI comm antenna on the belly for the #1 Comm, a clone (there were plans floating around the web) of an Archer antenna in the right wing tip (installed in a horizontal plain) for the VOR/LOC/GS, and another Archer clone in the left wing tip, installed diagonally (upper to lower surface of the tip) to get some vertical polarization for the #2 Comm. Performance for the VHF Nav was initially good (not Outstanding), but has steadily degraded (I have gone through all connections for corrosion, and have found none.) to the unacceptable level. The Comm #2 performance has always made that a formation/ground control/ATIS inside of 30 miles radio. No change there, but annoying when I have a good radio working through a not-so-good antenna.

So...i am thinking of upgrading. I'd rather NOT add another external comm antenna, since it would end up being non-symmetrical on the belly (in order to get good distance to #1 Comm), but will if I have to. I'd really rather not add VOR whiskers, as I don't like them on the tips of a tail dragger, and putting them underneath the horizontal tail will take some significant work. I could be REAL Archer antennas - the cheapest option - if I can get good performance from them. There are also some Antennas from Advanced Aircraft Electronics that ACS sells, primarily for use in plastic airplanes - I wonder if anyone has tried them in their RV tips. I have even thought of a Rubber Ducky mounted by the mid-cabin brace for the #2 Comm, but wonder if I could get 50+ mile performance out of it.

Before any of the side-by-side folks say "put a Comm antenna on top of the Fuselage - you can't do that on an -8 - there is no room with the big sliding bubble.

So - anyone want to contribute experience/thoughts? If someone says "I've been using my Archers for Nav for 5 years and have 100 mile range!", I'd probably order today!

Paul
 
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I have an "actual" Archer nav in the right wing tip and its performance is marginal at best. I've been thinking about whiskers too. I can just barely stay legal with its reception at some IFR published MRAs.
I recently went back and replaced my aluminum tape ground strip to tie the antenna ground to the wing skin with some nice copper tape, scuffed up the skin surface some more, checked connections all the way back to the radio (GNS430W), and confirmed that my wingtip wiring was tied correctly up the leading edge of the antenna...
In best cases, with no airframe blanking, in flat terrain, I get about 35-40mi. at about 4500' agl.
 
Doesn't have to be on the fuselage.

You can add a com antenna to the bottom of the wing. Great ground plane.
 
Well...

I was going to type that I've been flying with an Archer nav antenna since 2004 and have never had any trouble picking up the next vor. So I went to SkyVector to see how far away I've been able to pick up a VOR. On my trips from Iowa to San Antonio, we usually stop at KRKR for fuel, then routed around DAL to the Cedar Creek (CQY) VOR, then KSAT. So the distance from KRKR to the CQY VOR is 187NM. I've had no problem navigating this distance. Then I realized, oh yeah, I'm using the GPS side of the Garmin 430.

So, I'll still tell you that I've been flying with the Archer nav antenna since 2004 and have never had any trouble picking up the next station, just don't know how far that station has actually been. :)

Seriously though, I do tend to play with the VOR on the GPS fairly regularly on long trips and I've never had a problem reaching the next VOR. Just don't know the true distance.

Doug
 
I was going to type that I've been flying with an Archer nav antenna since 2004 and have never had any trouble picking up the next vor. So I went to SkyVector to see how far away I've been able to pick up a VOR. On my trips from Iowa to San Antonio, we usually stop at KRKR for fuel, then routed around DAL to the Cedar Creek (CQY) VOR, then KSAT. So the distance from KRKR to the CQY VOR is 187NM. I've had no problem navigating this distance. Then I realized, oh yeah, I'm using the GPS side of the Garmin 430.

So, I'll still tell you that I've been flying with the Archer nav antenna since 2004 and have never had any trouble picking up the next station, just don't know how far that station has actually been. :)

Seriously though, I do tend to play with the VOR on the GPS fairly regularly on long trips and I've never had a problem reaching the next VOR. Just don't know the true distance.

Doug
Man, I would love to see a picture of your magic VOR antenna installation :). Oh, yeah, it is that round thing on top that says Garmin on it :). I still feel like I'm doing something wrong with mine to get such marginal performance, but now Paul is making me feel much better.
 
I have a Bob Archer VOR wingtip antenna and pick up VOR's from a long way out. I have flown circles to see if I could see any real directional difference, and didn't see any. All this was done quite some time ago - I'll do some more testing this weekend if I can remember how to dial up a VOR...
 
Symmetry

Paul,

If you want symmetry under the wing (and relatively easy installation to boot), think about moving your existing comm antenna to one of the most-inboard access cover plates under the wing, then add the second antenna on the same cover plate on the other wing. That will give you the requisite distance apart. I'd think you could run the coax without removing the wing, although you might have to be creative with anti-chafe measures.

I've seen one RV-8 with a cat's-whisker VOR antenna mounted in the horizontal plane under the cockpit area. Other than looking a tad odd, it seemed to work OK. But knowing your sense of order, I think you'll probably be happier with a hidden wingtip nav antenna of some kind. :)
 
So - anyone want to contribute experience/thoughts? If someone says "I've been using my Archers for Nav for 5 years and have 100 mile range!", I'd probably order today!

Paul

I can't quite reach those parameters, but I've had a genuine Archer antenna installed in the right wingtip of my -7A for the past 3 years. The Garmin MD200-306 CDI connected to my SL-30 perks right up and reliably shows a good solid signal between 85 & 90 nm from the station at cruise altitudes between 6000 & 10,000 ft.

ILS localizer and glide slope reception is also unwavering during an approach. I've used it down to actual minimums of 200 and 1/2 with complete confidence.

I tried to install it per Bob's instructions and don't want to even touch, adjust or fix what quite apparently isn't broken. I'm very pleased.
 
az_gila;306085PS ...the "plans floating around on the web" are right here on VAF....:) [url said:
http://www.vansairforce.net/articles/vorwingtipantenna/wingtip_vor_antenna.htm[/url]

I never knew that was there Gil....and it is actually different than what I had when I built mine - so there are TWO sets of plans floating around out there....
 
I presume your antenna is...

I never knew that was there Gil....and it is actually different than what I had when I built mine - so there are TWO sets of plans floating around out there....

...a similar shape though....:)

Did you use stainless stock?
 
Oh yes - the actual antenna looks and is built the same - I had a drawing that came off someone's web site that was more clearly drawn. And it's not stainless - just alclad.

Paul
 
Guys, I have an original Archer comm antenna purchased directly from Bob and it is made out of 2024.
 
Thanks Bob...

Guys, I have an original Archer comm antenna purchased directly from Bob and it is made out of 2024.

...must be a fading memory....:)

Perhaps a cleaning of the co-ax wiring attachement screws and the addition of star lock washers might help the long term performance....
 
So, I'll still tell you that I've been flying with the Archer nav antenna since 2004 and have never had any trouble picking up the next station, just don't know how far that station has actually been. :)

Seriously though, I do tend to play with the VOR on the GPS fairly regularly on long trips and I've never had a problem reaching the next VOR. Just don't know the true distance.....Doug
I frequently switch the GI-106A to receive either a GPS signal or VOR station via an Archer antenna hidden in a wingtip. By changing the date to 2005 (pulled from the above quote), I have to report the exact same experience. I have never had a problem acquiring a VOR station I happen to choose to tune in. In fairness though, I cannot claim to know the precise distance or altitude I happened to be at relative to the VOR station at any given time.
 
I think we need DATA

For the Archer style gamma match antennas that are not performing up to expectations, it would be very nice to know the SWR of the poorly performing installation.

If I understand the tools needed to diagnose a nav antenna, it would include an SWR meter (I have one) and a signal generator to push the right frequency out the coax feed line to the antenna (don't have one but think I can obtain from a HAM aquantence).
 
Archer VOR antenna data points

Here is a bit of real world data. My receiver is a Garmin 430, antenna genuine Archer 2000 vintage.

At 5200' agl, I dialed in BRD, which was 68 n.m. away. I did a 360 turn, maybe 20 degree bank. There were two short (3 or 4 seconds) periods where the signal was lost, and the flag came up, otherwise good. Another VOR RPD, 58 n.m., 5200' agl, full circle ok, dropped out for about 20 degrees of turn. FGT, 46n.m., 5200' agl, full circle no problem. DWN, 58 n.m., 6400' agl, full circle no problem. FGT, 45 n.m., started at 6400' agl, circled down until first los (flag), first los at 3700' agl.

I saw no pattern to the drop outs, but it was always to the side somewhat. I suspect there is a pattern, I just didn't have time to really work on it. I should have dialed up a more distant VOR and put the nose and tail on it.
 
Excellent data Alex - thanks for contributing! it sounds like for Nav, the authentic Archers perform farily well. I traded emails wth Bob Archer, and have learned that the clones are probably missing the mark on several key parameters - according to him, the capacitance is very critical on the feed - I can tell you htat on the one I built, I have no idea what that was.

Anyway, hopefully this thread will help folks out in future searches....

Paul
 
Toy

The MFJ antenna analyzer is a handy tool for roll your own antennas. You can fine tune your antenna project to your planes installation. I can make 1-1 antennas all day long in the work shop, but stick it on the plane and things change:confused: It also can check coax and a host of other related stuff.
I have the MJF-259B, another fun toy for the tool box.:cool:
 
Antennas in the the gear legs

I had two antennas in the gear legs in my 6A. I used one for FM radio and the other for my handheld com. I never tested them for performance, but they seemed to work OK. All I did was strip off the shielding from a length of coax and glass it inside the leading edge of the fairing. I used a bulkhead coax connector where it entered the fuse, so that I could unhook them to remove the fairings. If memory serves, I think 21 inches is the correct length for a COM (or FM) antenna.
 
Updates and Progress!

Well, this has been a fun few days as I wander in and out of the hangar....

Several VAF'ers have responded to me off-line, and offered spare Archer Antennas that they had in their "unused parts boxes" for me to try. I received a Nav antenna the other day, and went in to my wingtip to replace the home-made one I had there. (One thing I noticed is that my Nav light wiring was not secured according to Bob Archer's instructions, and that might very well have caused a large part of the problem.) Someone else is sending me an unused Comm Antenna, and another is shipping me a spare AAE Comm antenna - I intend to try both of those and report back!

In addition, I Pete Howell is building a custom "J-Pole" antenna that should work for VOR, and I am definitely fascinated by the idea of giving that a try. Anything that sounds that cool must be tried! (I have no idea what a "J-Pole" is...:rolleyes:)

I also have exchanged emails with Bob Archer himself, as well as the Jerry Chambers at Advance Aircraft electronics, learning interesting things from both. Jerry didn?t hold much hope for the AAE Comm antenna in the RV, but if I am in the tip, I will probably try it. Bob told me that lots of folks who build the copies miss essential trimming that makes it work.

After putting in the new Archer Nav antenna, and dressing the cabling properly, I launched for a test flight. I brought up the list of ?nearest? VOR?s on my 396 screen, and started tuning them in, starting with the closest one. Climbing to 5,000?, I could tell that I had gotten better results already ? but the farthest one I could pull in reliably was at about 60 miles. I then tuned in the ILS at our nearest field, and line dup on final about ten miles out. Localizer was strong (as before), but the glide slope still didn?t come in until right at the FAF. Hmmm?.that got me thinking ? why split the signal? The Garmin 430 has a separate antenna feed for VOR/LOC and GS. I had been feeding them from a single antenna through a splitter, essentially giving away signal strength to each.

I landed and dugout my copy of bob Knuckoll?s book, turning to chapter 13 ? the mystical antenna chapter. He has some interesting designs for home-built VOR and Glide slope antennas (including a copy of an Archer antenna), but he stops just short of explaining how you hook up the Glide slope. Take a look for yourself ? tell me how you hook the Coax up at the antenna end! But then I re-read his text (and several old posts) about how tolerant the Glide slope is to antenna characteristics. OK, I had read about stripping a Coax back 16? and hooking it up ? so I found a chunk of coax, stripped it appropriately, pulled a few avionics, and rerouted my antenna lines. I took out the splitter and ran the wingtip antenna directly to the VOR/LOC portion of the 430. I then took the makeshift antenna I built, velcroed it to the roll-bar of the -8 (that mirror Velcro is good for something!), and hooked it into the GS portion of the 430. Time for a flight check!

IMG_7013.JPG


Results were great! I now could pull in VOR?s at the 80 mile range from 5,000?. Tuning in the ILS, I had the Glide slope at 10 miles, and proceeded outbound, reaching 18 miles before I had to turn around due to airspace limitations (the glide slope still locked on), and shot the approach ? strong all the way in! So?.splitting the signal gave a noticeable degradation in signal strength, and the wingtip antenna really wasn?t doing a very good job for the glide slope. Here?s a picture of my ?test? GS antenna ? next task will be making it permanent ? I might even put it in the lower cowl.

Next up will be playing with the Comm antennas (I might even try the stripped Coax down the gear leg like Jon Baker suggested) ? and testing that magical J-pole. I?ll update everyone when I have some results!

When it comes to antennas, I remember what an old time engineer taught me ? it?s all ?FM? ? and the EE?s out there will know what I mean?..;)

Paul
 
Hmmm.... Similar situation with the GNS430 / splitter, and all. I'm drooling over an 80 mi. vor. Keep writing so I don't have to reproduce your testing :). I just spent the whole day under the panel trying to get GRT "GNAV" working to no avail.
 
RF engineer viewpoint

An ideal splitter will cause 3dB of loss... which is half the power. Sounds worse than it is though, but it's pretty noticable at the outer edge of the VOR coverage. Worth 10's of miles for sure.

This is an enjoyable thread... it's got me thinking that I don't have a NAV antenna solution. I may go with the whiskers and sacrifice a bit of speed for good performance.
 
Could you have had a poor splitter?

An ideal splitter will cause 3dB of loss... which is half the power. Sounds worse than it is though, but it's pretty noticable at the outer edge of the VOR coverage. Worth 10's of miles for sure.

This is an enjoyable thread... it's got me thinking that I don't have a NAV antenna solution. I may go with the whiskers and sacrifice a bit of speed for good performance.

I'm sure you can find someone nearby at work to test it for you...:)

As Dave said, whiskers will work for the glide slope.

Did I remember someone on VAF putting a copper tape whiskers equivalent antenna for GS on the inside of the cowling??
 
I'm sure you can find someone nearby at work to test it for you...:)

As Dave said, whiskers will work for the glide slope.

Did I remember someone on VAF putting a copper tape whiskers equivalent antenna for GS on the inside of the cowling??

Good question Gil - I actually replaced the splitter with a known good one (that we had taken out of Mikey) a few months back. Now I have TWO surplus, expensive splitters.....;)

I thought I remember the same thing about a copper foil GS antenna in the cowl - searched and couldn't find it. The stripped Coax helped me confirm that I want the separate antenna - now I'll do a little more research before making my final version - anyone know if there is a better length than 16" (I got that from Knuckoll's dipole design in his book)?

Paul
 
It's all FM

When it comes to antennas, I remember what an old time engineer taught me ? it?s all ?FM? ? and the EE?s out there will know what I mean?..

Ah yes, FM. EE's may understand it, but back in my Air Force days, we technicians actually harnessed FM to resolve our most difficult avionics problems -- like those related to a loose nut in the cockpit. The resolution field of those trouble tickets often read "FM adjusted". ;)
 
Antenna facts

A few facts come to mind in this discussion.

Internal wingtip antennas will always have an asymmetrical pattern, whether for transceive or receive. Specifically, they will exhibit multiple deep performance nulls towards the rest of the airplane. Unless the tips are RF transparent, i.e. scraps won't heat in a microwave is a good test, they will also attenuate both the receive and transmit signals.

Obviously then, antennas on the bottom of the fuselage work better with ground stations, on top, with air to air. On the day job big airplane, we sometimes have to switch radios based on bottom/top antenna just to talk to ramp/ground/clearance/etc., not very often, but it happens.

It is difficult to get a completely symmetrical antenna pattern even with fuselage mounted antennas, much more difficult with wing antennas, even when externally mounted.

Comm needs vertical polarity and VHF Nav horizontal. The penalty for cross polarization re to another station is a 20db path loss.

Antenna length in feet is 234/freq(mhz) or 468/freq(mhz), for 1/4 WL whip or 1/2 WL dipole respectively. The length of the coax normally does not present a matching problem, but db loss as a function of coax length does matter. RG-58 is very lossy. Buy the good stuff, including good connectors. We hams usually wrap all connections with Coax Seal but poor connections will still get degraded by moisture over time.

A dipole's impedance is 72 ohms. Bending it to roughly a 120 degree included angle gets it closer to 50 ohms, i.e. closer to 1:1 SWR, what the connected device wants to see, whether xmt or rcv. If you have to change the length of an antenna already cut to the proper length and bend to achieve a lower SWR at a given resonant freq, then something is detuning the antenna, and will degrade its performance. Where a whip antenna (1/4 WL) is concerned, a min SWR not near 1:1 at resonance is indicative of a poor RF ground plane, which is different from a DC ground.

If you want to play with antennas, consider the MFJ-259B antenna analyzer. It generates a low level signal which is used to determine resonant freq of antenna, also resistance and reactance, from 1.8-170 mhz. This unit can also be used as a signal generator and freq counter, easily accurate enough to check Comm or Nav radios, including handhelds.

I know there are some strong opinions out there about where/how to mount antennas, especially from some vendors of wing tip antenna kits, but the facts are what they are.
 
REAL Bob Archer VOR antenna's

A few facts come to mind in this discussion.

Internal wingtip antennas will always have an asymmetrical pattern, whether for transceive or receive. Specifically, they will exhibit multiple deep performance nulls towards the rest of the airplane. Unless the tips are RF transparent, i.e. scraps won't heat in a microwave is a good test, they will also attenuate both the receive and transmit signals.

Obviously then, antennas on the bottom of the fuselage work better with ground stations, on top, with air to air. On the day job big airplane, we sometimes have to switch radios based on bottom/top antenna just to talk to ramp/ground/clearance/etc., not very often, but it happens.

It is difficult to get a completely symmetrical antenna pattern even with fuselage mounted antennas, much more difficult with wing antennas, even when externally mounted.

Comm needs vertical polarity and VHF Nav horizontal. The penalty for cross polarization re to another station is a 20db path loss.

Antenna length in feet is 234/freq(mhz) or 468/freq(mhz), for 1/4 WL whip or 1/2 WL dipole respectively. The length of the coax normally does not present a matching problem, but db loss as a function of coax length does matter. RG-58 is very lossy. Buy the good stuff, including good connectors. We hams usually wrap all connections with Coax Seal but poor connections will still get degraded by moisture over time.

A dipole's impedance is 72 ohms. Bending it to roughly a 120 degree included angle gets it closer to 50 ohms, i.e. closer to 1:1 SWR, what the connected device wants to see, whether xmt or rcv. If you have to change the length of an antenna already cut to the proper length and bend to achieve a lower SWR at a given resonant freq, then something is detuning the antenna, and will degrade its performance. Where a whip antenna (1/4 WL) is concerned, a min SWR not near 1:1 at resonance is indicative of a poor RF ground plane, which is different from a DC ground.

If you want to play with antennas, consider the MFJ-259B antenna analyzer. It generates a low level signal which is used to determine resonant freq of antenna, also resistance and reactance, from 1.8-170 mhz. This unit can also be used as a signal generator and freq counter, easily accurate enough to check Comm or Nav radios, including handhelds.

I know there are some strong opinions out there about where/how to mount antennas, especially from some vendors of wing tip antenna kits, but the facts are what they are.

Bio - Bob Archer designed antenna's for TRW. He has lived the facts for the design of the "GAMA" wingtip antenna design. No guesswork, no opinion's. Just cold hard test data taken on an aircraft signal range.

My Opinion - If you want a solid wingtip VOR antenna installation, buy the Sportcraft Antenna (Bob Archer's) AND READ THE INSTALLATION INSTRUCTIONS.
A "real" Bob Archer antenna mounted in accordance with the instructions is the best possible installation for a VOR antenna. Any other mounting location will have poorer overall performance.

Information from Bob Archer - The "GAMA" antenna receives the VOR signal from the ground plane. The airframe itself. There will be two very sharp null points in the signal. One directly across from the antenna location. And one at a 45 degree angle behind the aircraft on the side the antenna is mounted. These null points are supposed to be so sharp that they can not be held to loose the signal.
The capacitance between the GAMA antenna element and the GAMA antenna ground plane is CRITICAL. A physical copy of Bob Archer's antenna design probably won't even be close on this.
(My interpretation of Bob's comments.)
A friend of mine tried to copy Bob Archer's VOR antenna with very limited success. I finally gave him a real Bob Archer wingtip VOR antenna.

I've had a Bob Archer wingtip antenna in my RV-3 for the last 20 years. It has at least 10 miles more range than a stock external VOR antenna on a Cessna 210.

Regards,
Jim Ayers
 
My Opinion - If you want a solid wingtip VOR antenna installation, buy the Sportcraft Antenna (Bob Archer's) AND READ THE INSTALLATION INSTRUCTIONS.
A "real" Bob Archer antenna mounted in accordance with the instructions is the best possible installation for a VOR antenna. Any other mounting location will have poorer overall performance.

Regards,
Jim Ayers

I agree with Jim. In the right wingtip of my -7A, an 80nm reception range with the "real" Archer antenna is the norm.

Mike
 
I wonder how Comant Towel Bars

I wonder how Comant Towel Bars are going to work in the wingtips. I used two Comant whip antennas on the belly, but my mentor Rich Janoski is using homemade com antenna inside his gear legs & says they're about 98%. I have a feeling I'm going to be selling two comant C122's pretty soon and plugging some holes.
 
Update on the Trials...

It's been a couple of weeks since I could concentrate on this little project due to work obligations, but I was able to find a little time to install the REAL Archer Comm antenna the other day. I paid very careful attention to the routing of lighting wires and cables, instructed by Bob Archer, and the results were markedly better than what i had with the home-made version. I am picking up ATIS's at 50 miles, whereas I used to get them at 20. I still have a completely unreadability problem if the HID light is turned on in that wing, but that is the price I will have to pay if I want to have a hidden antenna there.

I did not get get a chance to try the AAE yet, or Pete Howell's J-Pole - hopefully after a week's vacation I can come back and temp up both in the wingtips for some testing. The AAE fellow was not hopeful, but it's only fifty screws to get the tip off...and back on...and back off...and ....

I am really interested in the J-Pole though, and that will definitely be worth the time! I have a very good baseline of the distance I can get stations now, so a true comparison should be pretty easy.

Interestingly enough, while the Comm is blown away when the HID's are on, the NAV doesn't react at all.
 
I am really interested in the J-Pole though, and that will definitely be worth the time! I have a very good baseline of the distance I can get stations now, so a true comparison should be pretty easy.

Paul, if the J-Pole isn't the final nav solution, you have a good start on an APRS rig. :)

APRS would be just the ticket for watching Louise as she commutes. Go ahead, you know you want to try APRS........ ;)
 
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Related Question...Archer/J-Pole + APRS antennas in a wingtip

Sam, Pete, Paul and others:

Been watching this with interest, as I'm doing some planning musings as well.

I'm considering a trade-up from an SL-40 to an SL-30 to add ILS/VOR capability. I like the idea of an Archer or J-pole in the wingtip, but am also contemplating an APRS rig (have a SPOT now, but I like the more frequent APRS hits, so will likely drop the SPOT tracking feature, keeping it as a PLB, and join the APRS throng).

Need to get more edu-macated on APRS rigs, and will do so before proceeding, but my planning question is, would I be able to place a Nav antenna (Archer or J-pole) in the same wingtip as the APRS set-up and antenna, or will I need to split them between wingtips?

Thanks much, and very interested in how your comparison tests play out Paul, as I will very likely follow your lead on the Nav antenna!

Cheers,
Bob
 
Sam, Pete, Paul and others:

Been watching this with interest, as I'm doing some planning musings as well.

I'm considering a trade-up from an SL-40 to an SL-30 to add ILS/VOR capability. I like the idea of an Archer or J-pole in the wingtip, but am also contemplating an APRS rig (have a SPOT now, but I like the more frequent APRS hits, so will likely drop the SPOT tracking feature, keeping it as a PLB, and join the APRS throng).

Need to get more edu-macated on APRS rigs, and will do so before proceeding, but my planning question is, would I be able to place a Nav antenna (Archer or J-pole) in the same wingtip as the APRS set-up and antenna, or will I need to split them between wingtips?

Thanks much, and very interested in how your comparison tests play out Paul, as I will very likely follow your lead on the Nav antenna!

Cheers,
Bob

Bob, I think Kahuna has a J-pole and Archer antenna in the same wingtip, maybe he will chime in with his experience. I know his APRS rig works nicely, but haven't heard him comment on any impact on the nav antenna. I would probably put them in different wingtips just to make sure there wasn't any crosstalk.

Then again, I would probably use a belly-mounted whip for APRS. :)

Happy tracking!
 
Thanks Sam,

Good info!

Digesting the APRS info on the forum now (sure is a lot!! :)), and will smarten up and dive in! Thanks much!

Cheers,
Bob
 
Going to try the Archer!

Well, I guess I'm going to try the Archer wing tip for my VOR. A can't seem to find his address, however, can anyone post it? Also it seems that it works better if you avoid a splitter and use separate a separate GS antenna, is this also true for the marker beacon?


Thanks

GEM
 
My Archer

Works just fine with a splitter.

For the marker bacon you just want a 37 inch length of bare wire...I just stripped the outer sheild off a lenght of RG58 and glasses it into my lower cowl.

I have a BNC connection I have to connect when putting th cowl back on.

Works just fine

Frank
 
HID installation issues?

It's been a couple of weeks since I could concentrate on this little project due to work obligations, but I was able to find a little time to install the REAL Archer Comm antenna the other day. I paid very careful attention to the routing of lighting wires and cables, instructed by Bob Archer, and the results were markedly better than what i had with the home-made version. I am picking up ATIS's at 50 miles, whereas I used to get them at 20. I still have a completely unreadability problem if the HID light is turned on in that wing, but that is the price I will have to pay if I want to have a hidden antenna there.

I did not get get a chance to try the AAE yet, or Pete Howell's J-Pole - hopefully after a week's vacation I can come back and temp up both in the wingtips for some testing. The AAE fellow was not hopeful, but it's only fifty screws to get the tip off...and back on...and back off...and ....

I am really interested in the J-Pole though, and that will definitely be worth the time! I have a very good baseline of the distance I can get stations now, so a true comparison should be pretty easy.

Interestingly enough, while the Comm is blown away when the HID's are on, the NAV doesn't react at all.

Paul, whose HID are you using?
-asks a guy who has a box of Xevision HID wigwag stuff already....
 
my Archer antenna no workie

I been following this thread with much interest. One of the squawks that I have to trouble shoot is very poor VOR antenna performance with my GNS480. I can hear a weak morse ID but I always get a "Flagged" indicator when switch the CDI from GPS to VOR.

I've have real Archer and the signal improved slightly when I used some aluminum tape to improve the ground. I bought some copper tape that I'm going to try next.

One place that I deviated from the instructions is wire routing. I placed the antenna towards the aft end of the wing tip. The front of the antenna is just about in the middle of the wing tip. I routed the wires so that they are well forward of the antenna - there's at least 12" between the antenna wires for the lights.

Any thoughts on whether the ground or the lighting wires are the major culprit?
 
I been following this thread with much interest. One of the squawks that I have to trouble shoot is very poor VOR antenna performance with my GNS480. I can hear a weak morse ID but I always get a "Flagged" indicator when switch the CDI from GPS to VOR.

I've have real Archer and the signal improved slightly when I used some aluminum tape to improve the ground. I bought some copper tape that I'm going to try next.

One place that I deviated from the instructions is wire routing. I placed the antenna towards the aft end of the wing tip. The front of the antenna is just about in the middle of the wing tip. I routed the wires so that they are well forward of the antenna - there's at least 12" between the antenna wires for the lights.

Any thoughts on whether the ground or the lighting wires are the major culprit?


Rick,

I asked this exact question of Mr. Archer himself a few weeks ago, and his answer is that the wire routing is critical - the wiring essentially becomes part of the antenna, and if it is routed across the antenna elements (other than as shown on the drawing), it steals signal. I also thought I]'s solve the problem of light wiring by having the antenna farther aft, but this didn't work well - I remounted it forward, with the wiring as suggested, and got better performance. These antennas work, but do not lend themselves to intuitive answers!

Paul
 
antenna element needed

Realize this is not the classiifeds, but if anyone has gone to a tip mount nav antenna, and has a surplus CI-159 Comant V dipole (CI-158 will work also), I need a replacement element or will buy the whole antenna. The element needs to be 1/4" diameter at base and tapered outward, approx 23" long, with 1/8" threaded mounting. Painted white with anti static stuff is a plus. Thanks......pls use PM.
 
Archer wingtip COMM antenna Pictures?

Paul or anyone with an Archer COMM antenna installation,

Do you happen to have any pictures of the installation of your Archer COMM antenna? If not, is it oriented vertically or horizontally like the Archer NAV antenna?

Thanks!
 
Paul or anyone with an Archer COMM antenna installation,

Do you happen to have any pictures of the installation of your Archer COMM antenna? If not, is it oriented vertically or horizontally like the Archer NAV antenna?

Thanks!

No pictures handy, but it is oriented diagonally - lower edge of wing tip where it joins the tip rib, to upper surface about halfway out to the tip. I just made a bent bracket that holds it at the tip rib edge, and glassed in a piece of cloth on the top to hold it there. Gives the most vertical polarization available in the tip.

Paul
 
More Antennas

Hi All

I just happen to be at the point of making the tough antenna choices and of course been following this muses with interest. I'm building a 7a with a PS Engineering 7000 with marker beacon, 430w, IC200 and 327 transponder. I have a HID from Duckworks in the left wing, a halogen in the right and will be running Aero LED's new nav/strobes. I shall now expose myself to your scrutiny. My rough plan is to place an Archer Nav antenna and a separate GS stripped cable in the left wingtip. An Archer Com antenna for the 430w and a marker beacon wire or strip in the right wingtip. And finally a basic whip antenna on the bottom of the fuselage for the IC200. Oh sorry, a standard transponder antenna too. Thoughts and comments welcome.

Thanks

Peter Richmond
 
Your plan sounds fine to me with one exception - I'd definitely use the "good" comm antenna for the 430W Comm - That is most likely going to end up as your number 1 Comm (it is for most), and you might as well give it the best antenna.

Paul

Hi All

I just happen to be at the point of making the tough antenna choices and of course been following this muses with interest. I'm building a 7a with a PS Engineering 7000 with marker beacon, 430w, IC200 and 327 transponder. I have a HID from Duckworks in the left wing, a halogen in the right and will be running Aero LED's new nav/strobes. I shall now expose myself to your scrutiny. My rough plan is to place an Archer Nav antenna and a separate GS stripped cable in the left wingtip. An Archer Com antenna for the 430w and a marker beacon wire or strip in the right wingtip. And finally a basic whip antenna on the bottom of the fuselage for the IC200. Oh sorry, a standard transponder antenna too. Thoughts and comments welcome.

Thanks

Peter Richmond
 
Stay away from the wing-tip comm antennae. You will NOT be happy nor will the radio. Use two external mounted comm antennae one on the belly and one on the top if possible will give you the best isolation and coverage. the top antenna you will use mostly for ground communications. In the air either will work just great.
 
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