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Archer antenna

SMRacer

SMRacer

Well Known Member
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I have a recent panel modification to all glass AFS. No GPS Navigator. Thus I am depending on ILS for IFR approaches. I am getting marginal reception of localizer/glide slope and would not be comfortable flying IMC with this level of reception. I have an Archer antenna installed in the left wingtip. Purchased the airplane flying. Here is a pic of the Archer antenna. Is there anything obvious that might be causing the poor reception?
 
It needs to be flipped, left right!
The side which is shown right needs to be electrically attached to the metal wing and end rib. One way would be to remove the nutplates, slide the now right, soon left, arm under the nutplates and re-rivet. Or just rivet a few aluminum straps to the antenna and the metal nutplate backing strip. Make sure there's no paint under the attach screws between the wing and the nutplates.
The arm shown left, should be right, will be outboard. Use some epoxy or fiberglass to keep it from floping around.

PS Hard to tell in the photo, but the piece at the bottom should, in flight, be reasonably horizontal.
PPS Amazing it works at all, as it is!
 
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Do you have the installation instructions? If so, those would be a great place to start. In addition to everything Bob said above, I recall the instructions wanted wires to not be perpendicular to any portion of the antenna.
 
Yep. Agree with Bob. Needs to be flipped and grounded through the nut plates to the wing. I have the same antenna in my Rocket and reception is rock solid.
 
Soooo....

So I need to drill holes in the short arm on the right and sandwich this part under the nut plates? The point of the antenna will now face to the rear?
 
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Jim,

This is how my Archer NAV antenna installation looks -

DSCN1173.JPG
 
Careful with the com antenna in the wingtip, that signal is polarized vertically and you will have less-than-optimal performance with a wingtip com antenna. Nav is polarized horizontally and works just fine.

Do a search on the forums here, it's been discussed at length. Try searching on "polarization" and ignore the sunglass parts. :cool:
 
Installation instruction question

The instructions state - Remove the 3 flat head screws and clamps from the front antenna strip.

I don't see any screws or clamps on mine (new out of the package). What do these look like? Are these the three plastic Adel-like clams that I see in the picture of the first post?
 
Vansconvert said:
The instructions state - Remove the 3 flat head screws and clamps from the front antenna strip.

I don't see any screws or clamps on mine (new out of the package). What do these look like? Are these the three plastic Adel-like clams that I see in the picture of the first post?
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Yes. Since I didn't need to run any wires over my antenna I just removed and discarded those 'Adel-like' clamps. If you need them just use standard hardware, get some plastic clamps at Radio Shack.
 
SMRacer said:
So I need to drill holes in the short arm on the right and sandwich this part under the nut plates? The point of the antenna will now face to the rear?
Click to expand...

I see no one answered.
Yes, the short arm, now right, needs a good, short electrical connection to the metal end rib and wing skin. Best way is to sandwich it under the nut plates.
The piece of the antenna with the 3 clamps on it is responsible for most of the reception. Most builders place this end fairly far forward, to minimize any shadowing by the wing. I think you are asking if that end can go aft. To be honest I have not noticed, but seldom look, to see if there is any degradation in signal when flying the localizer outbound (flying a normal Archer outbound is similar to flying inbound with the 3 clamp-piece aft). You can try it.
Alternatively, put the 3 clamp piece forward and use some styrofoam blocks to protect the wingtip from the bolt ends (this is why Archer sells 'left' and 'right' models). Alternatively you could mount the whole thing to the top of the wingtip.
 
Success

It appears that there indeed is a "left" and "right" wingtip orientation. If you look at my original photo, I had to take the antenna apart and reassemble to use it on the lower surface of the left wingtip and still have the point facing forward.

I drilled out six nutplates and sandwiched the short side of the antenna underneath. The nylon clamps were used to guide the lighting harness.

A test on an ILS approach proved dramatic improvement of the localizer signal. The glideslope was a bit late to unflag, but steady once acquired.

Overall a huge success and another gripe removed from my list. Thanks for all the help I received from VAF.

PS: I have now purchased two flying RVs. I have come to realize that if a builder makes a mistake, and doesn't realize that mistake, AND does all the subsequent condition inspections, that the mistake will never be detected. Thus I would recommend that even if you do possess a repairman's certificate for your airplane, have some additional RV knowledgeable eyeballs observe an occasional annual inspection.
 
SMRacer said:
PS: I have now purchased two flying RVs. I have come to realize that if a builder makes a mistake, and doesn't realize that mistake, AND does all the subsequent condition inspections, that the mistake will never be detected. Thus I would recommend that even if you do possess a repairman's certificate for your airplane, have some additional RV knowledgeable eyeballs observe an occasional annual inspection.
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Always a good idea to have your work checked. And, if buying used, have a very knowledgeable A&P do a thourough pre-buy. But in this case it appears the antenna was just thrown into the wingtip, without ever trying to install it properly. Hard to mis-read the directions that badly. I would recommend you go thru all the avionics carefully. Perhaps your weak GS is related to an incorrect splitter??
 
Still not happy

So I've repositioned the antenna and rerouted wiring, but reception is still not great.

I noticed yesterday that flying OUTBOUND on the localizer I had very good reception on both localizer and glide slope out to about 8 miles. I then turned back INBOUND and got acceptable localizer reception and rather poor glide slope (glide slope flagged until almost the outer marker)

Installation shows the pointy end of the Archer antenna forward, but it almost seems like I'd be better off reversing that orientation.

Any suggestions?
 
IMHO 8 miles out is not up to par. You should easily get loc and GS at twice that distance. Given the poor work done by the original builder I would go thru the entire system. Look at the coax, connectors, signal splitter (if needed), as well as antenna ground (make sure the wing tip to wing screws are not insulated by paint under them.), etc.
 
Details

BobTurner said:
IMHO 8 miles out is not up to par. You should easily get loc and GS at twice that distance. Given the poor work done by the original builder I would go thru the entire system. Look at the coax, connectors, signal splitter (if needed), as well as antenna ground (make sure the wing tip to wing screws are not insulated by paint under them.), etc.
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I only flew out 8 miles. I'm sure the reception would have continued beyond that distance. What I'm wondering about is that reversing direction diminished the reception considerably.
 
SMRacer said:
So I've repositioned the antenna and rerouted wiring, but reception is still not great.

I noticed yesterday that flying OUTBOUND on the localizer I had very good reception on both localizer and glide slope out to about 8 miles. I then turned back INBOUND and got acceptable localizer reception and rather poor glide slope (glide slope flagged until almost the outer marker)

Installation shows the pointy end of the Archer antenna forward, but it almost seems like I'd be better off reversing that orientation.

Any suggestions?
Click to expand...

The "pointy end" orientation makes no difference, other than the base leg being closer/further away from the leading edge. I note that for most people, the Archer antenna base leg could be longer, going further out from the wing rib. I enjoy very good reception on my homebrew antenna.

You need to find a local Amateur Radio operator to come tune your antenna. The gamma match (that thing with the Bakelite strip) needs to be adjusted to make the appropriate impedance match. A ham radio guy can do this for you in a few minutes if he/she has a basic antenna analyzer.

I have several posts on wingtip antennas if you want more details.

Carl
 
Ignorant here. :confused: Do you use two of these, one nav and one com, in each wingtip if you have two nav and two com radios? One on top and one on the bottom of each wingtip?
 
By the pointy end I assume you mean the end close to where the coax attaches?
Is that end fairly far forward? It almost sounds like it's being shadowed by the wing.
Fairly easy test: build a half wave dipole for the GS (you can find it in a search). Tape it to the windscreen, run the coax directly to your GS receiver. Go fly. If that doesn't work inbound then the problem is in the receiver.

I have seen some installations with okay LOC but poor GS where the ground leg was not up against or very close to the wing rib. You cannot attach it with 8" of wire.
 
MED said:
Ignorant here. :confused: Do you use two of these, one nav and one com, in each wingtip if you have two nav and two com radios? One on top and one on the bottom of each wingtip?
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No.

One wingtip antenna for VOR/ILS. If you have more than one VOR/ILS you can either use one antenna and a splitter, or one antenna in each wing.

Use a couple of bent whip antennas on the belly for Comm #1 and Comm #2.

Carl
 
One more thing. You said you took it apart. Are you sure you put the parallel plate capacitor back together correctly? As Carl said, if you have a ham radio friend he may have test equipment to easily check this.
 
Thanks, Carl. I noticed the Aircraft Spruce links specified different antennas for nav and for com, even though they appear similar. I assumed using those you could hide both nav and com antennas in the wingtips, instead of having any external whips. Lots of questions to resolve later.
 
SMRacer said:
It appears that there indeed is a "left" and "right" wingtip orientation. If you look at my original photo, I had to take the antenna apart and reassemble to use it on the lower surface of the left wingtip and still have the point facing forward.

I drilled out six nutplates and sandwiched the short side of the antenna underneath. The nylon clamps were used to guide the lighting harness.

A test on an ILS approach proved dramatic improvement of the localizer signal. The glideslope was a bit late to unflag, but steady once acquired.

Overall a huge success and another gripe removed from my list. Thanks for all the help I received from VAF.

PS: I have now purchased two flying RVs. I have come to realize that if a builder makes a mistake, and doesn't realize that mistake, AND does all the subsequent condition inspections, that the mistake will never be detected. Thus I would recommend that even if you do possess a repairman's certificate for your airplane, have some additional RV knowledgeable eyeballs observe an occasional annual inspection.
Click to expand...

In your case, it would appear that the builder really struggled with following directions. I would probably be looking for other areas where this may have occurred.

I bought a partially completed kit and had to "undo" a fair amount of work.

Larry
 
MED said:
Thanks, Carl. I noticed the Aircraft Spruce links specified different antennas for nav and for com, even though they appear similar. I assumed using those you could hide both nav and com antennas in the wingtips, instead of having any external whips. Lots of questions to resolve later.
Click to expand...

Most find that even though the Nav antenna work great the Comm ant. don't.
Most use the bent whip on the belly.
 
For a comparison data point once you change your antenna installation... I have the archer antenna installed in my wingtip, with a splitter to connect to both a SL30 and a 430W. Even with 1/2 the power (from the splitter) going to both radios, I get very good GS and LOC signal 15 miles out on the KSNS ILS RWY 31. This approach is very long by design and has opportunities for reflections (if there is poor signal) due to 3000 MSL terrain on both sides of the approach course. The approach actually works better in my RV8 than the Cessna 172 I was flying on the same approach- the 172 VOR signal would wander over parts of the course.
 
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