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QB Wing Wing Tip Antenna Wiring

ERushing

ERushing

Well Known Member
I'm planning to put a Nav Antenna in my right QB wing tip. I'd like to route it out to the tip in a quiet 2nd conduit (primary conduit is for landing and nav lights.)

Having some difficulty figuring out how to secure the conduit in the Wing walk area that already has the bottom skin riveted on. A thought occurred to me - Could I run the coax inside the curved portion of the J-Stiffeners that run the length of the wing? Perhaps secure it to the stiffener with some Permatex or something like that.

Anybody tried that? If not, has anybody found a clever way to run a 2nd conduit in a QB wing?

Am I overthinking this? Do I really need to run the coax away from the higher power lines?

Thanks for any input!
 
You don't really need a conduit just for a coax. I'm planning to just use a separate hole with snap bushings.

You should be able to reach in through the lightening holes in the wing walk area until you mount the wings.
 
Something to consider. I installed an Archer antenna in each wing tip, one for each NAV radio. The VOR reception with both radios was great, but I noticed two issues with the LOC/GS with both radios. (430W and SL30)

The first is the antenna is offset from the center-line of the aircraft. While you would not think ~ 16 feet would be much, it was very noticeable when shooting an ILS approach that you were not centered.

The second issue I had was that I was also using the Nav wingtip antenna for GS reception. I found in certain banked attitudes, especially when getting vectored to final in a banked turn with the antenna on the outside wing of the turn, I would loose the GS signal. This would cause the autopilot to disconnect vertical guidance at a critical juncture in the approach.

I ended up installing a Nav antenna on the belly under the horiz. stab., which eliminated all the issues. I could have just as easily installed a separate GS antenna, but I wanted to eliminate the 16 ft. offset. I only use the belly antenna for the 430W and I still use the other wingtip antenna for the SL30 since it is really just a backup radio.

There is a separate thread on the discussion of the merits of the wingtip antennas.

IRT running wires. I choose not to use conduit. I ran the strobes in a separate grommet and the DC wires along side the coax.

IMG_1555.jpg
 
Weak reception

I have replaced a number of the wingtip antennas with belly mounted nav antennas due to the reasons mentioned in the previous post. Keep in mind that these wing tip antennas work much better in the fiberglass aircraft for which they were originally designed. The metal aircraft will block the signals, and it is especially noticeable when trying to capture ILS signals from the opposite side of the intercept.

Vic
 
vic syracuse said:
I have replaced a number of the wingtip antennas with belly mounted nav antennas due to the reasons mentioned in the previous post. Keep in mind that these wing tip antennas work much better in the fiberglass aircraft for which they were originally designed. The metal aircraft will block the signals, and it is especially noticeable when trying to capture ILS signals from the opposite side of the intercept.

Vic
Click to expand...

Has anyone here tried the stripped coax method for a glideslope antenna run down the main gear leg fairing on a 10? I have that setup on my RV-8 and it has worked well (and no external antenna with the drag added).
 
Thanks for the replies!

Bill - Did you use cat whiskers under the HS? How did you secure the lines running along the J-stiffener in your wing pic?

Vic - Any suggestion as to where to located it on the belly? At this point, I was planning on both Comm radios under the rear seats. I now wish I had installed cat whiskers when I built the VS! The only things I've planned on top of the airplane are the GPS pucks.

Thanks!
 
Eric-

You have a build log online somewhere? My QB kits will be here next week and I'm extremely interested in seeing the progress.
 
Procrastination

Hi Justin,

No Blog... At least not yet. I started one but didn't keep up with it so never posted it. I found that I liked building a lot more than blogging!! I use Vans plans as my log, marking off and dating every step. And inserting any description of anything done off plans or area of difficulty that I ran into.

I should just take a weekend and catch up on the posts and publish it... But that would be a weekend of not building 😀😀

I'm happy to post pics of anything you want to see.
 
I think it's fair to say that the Archer antennas are sensitive to installation details. Some have had issues. Myself, I've never had any problems with an ILS, whether vectored from right side or left, full procedure turn, etc. The vor is not as sensitive as an external antenna, especially when the antenna 'looks' thru the airframe. But I'm keeping mine.
Some of the issues I've seen include not mounting the grounded leg as close as possible to the outboard rib, or not having a good short electrical connection to the rib. With this antenna, the outboard rib is part of the design.
 
vic syracuse said:
I have replaced a number of the wingtip antennas with belly mounted nav antennas due to the reasons mentioned in the previous post. Keep in mind that these wing tip antennas work much better in the fiberglass aircraft for which they were originally designed. The metal aircraft will block the signals, and it is especially noticeable when trying to capture ILS signals from the opposite side of the intercept.

Vic
Click to expand...

Vic,

Not to start a war, but my home brew wingtip VOR antenna performs as well, if not better than planes I compared with using whisker type antennas. I offer that wingtip antennas do require some level of expertise to make sure they work.

I caution builders I talk to about the hazards of whisker VOR antennas, especially mounted on the bottom of the airplane. If someone installs one of these antenna, I hope they carry with them the required eye protectors. These belly or bottom of the HS mounted antennas present a significant eye hazard to kids, dogs, and pilots. This also applies to bottom mounted bent whip antennas. I have two and carry pieces of tubing with a red ribbon to cover them when not flying.

To the original question, there is perhaps marginal gain to physically separate the RG-400 nav antenna cable from the rest of the wing wireing. If you are running LED nav and strobe lights you can have significant RFI problems - but the RFI path is via the power and ground leads, not the radio or nav antenna cables. You can also get RFI in the nav radio if you mount the wingtip VOR antenna near the nav/strobe. Mount the wingtip VOR antenna as far aft into the wingtip as you can to minimize this issue. There are also specific installation instructions for LED nav/strobe lights so that you do not have an RFI problem.

Carl
 
Not flying the setup yet, but I'm putting Archer in the wing to feed a 430W and an SL-30.

16 foot offset doesn't seem problematic, unless you've discovered the unicorn of ILS/LOC approaches to a runway 50' wide with a MAP at 200' AGL. Usually if you're in the safe area 16' right or left should be a non-issue when you go visual.

GS "unreliability" while not on the ILS inbound track is a strange observation. If you're not on the approach course why are you looking at the GS? Complete your turn, confirm your GS reception and then decide if you're going to ILS or LOC minimums. You wouldn't descend on the GS when you weren't on the approach course, would you? The Altimeter is much more important at this phase of the approach.

Anyway, whiskers vs hidden antennae is an aesthetic choice and there isn't a wrong answer.
 
VOR/LOC vs GS antenna

Can someone clarify...Bill Payton mentioned possibility of a separate GS antenna. I notice the GNS 650 that I have only has a single nav antenna connector. Is there some kind of coax splitter that permits separate antennas? Is is needed?
 
bob888 said:
Can someone clarify...Bill Payton mentioned possibility of a separate GS antenna. I notice the GNS 650 that I have only has a single nav antenna connector. Is there some kind of coax splitter that permits separate antennas? Is is needed?
Click to expand...

No.

The GTN-650 connects only to the VOR antenna. The VOR antenna provides VOR reception and GS. The GTN-650 is not like the earlier generation of NAV/COMMs that required either separate VOR and GS antennas or an external splitter to use just a VOR antenna for both inputs.

GS frequencies are three times higher than VOR frequencies. Half wave or quarter wave antenna are resonate at the base frequency (in this case VOR frequencies) and at odd multiples of the base frequency.

Carl
 
'earlier generation'?

The SL-30 is probably 20 years old or more. It has only one nav antenna input, and has an internal splitter, just like the 650.
(And imho it's still the best nav receiver ever built.)
 
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Eric,
The lines you see in my photo are the Pitot and AOA. I just ran caterpillar flex grommet material on the rib side. The two lines hold themselves in.


I do agree, if you install the cat whisker nav antenna on the belly, make sure you have round balls on the end and they are painted orange. The more proper place to install this would be the top of the Vert Stab. I couldn't because it was already painted and flying.

IRT the separate GS antenna, some radios have individual antenna inputs for VOR/LOC and GS such as the GNS 430W and require a diplexer, The GTN650 does not.
 
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VOR/LOC vs GS antenna

Can someone clarify...Bill Payton mentioned possibility of a separate GS antenna. I notice the GNS 650 that I have only has a single nav antenna connector. Is there some kind of coax splitter that permits separate antennas? Is is needed?
 
A gtn 650 does not require a diplexer. You would only need a splitter if you were to use a single antenna with two radios.
 
Bill,

Do you have any closer pics of the cat grommet install? I looked at a couple sites and it looks interesting. I'm just not sure how it works! Do you size the grommet for the wire/ pitot diameter? In my case, coax? I might also run the aoa line down the same run.

Thanks!
 
Eric,
You purchase it by the foot. It's just an edge trim that you cut to length. I bought it locally, but I would guess that you could find it online. I use it anywhere I need rub protection on an edge. It protects a wire from rubbing on an edge. You could install it on any size hole such as a large lightening hole. Ill look for a closer photo http://www.skygeek.com/brown-aircra...aign=froogle&gclid=CIPut9aj9csCFUdrfgodOBkPeQ
 
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