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Pilot135pd
01-30-2020, 07:24 PM
Since this thread went in the direction of antennas I edited it and made another thread asking about the autopilot. I'm adding the VAL INS-429 to my panel and wanted to know if anyone has installed the LOC/ILS antennas in their wingtips? I was thinking about separating them or just plain building 2 new dipoles and installing them in the fiberglass wingtips instead of installing this ugly draggy antenna on the fuse. If there's no other choice I'd install it under the fuse under the pilot seat so it can't easily be seen from outside. I'm also trying to avoid the extra drag.

https://i.imgur.com/7aquSZx.png



*** If a Mod needs to move it to another section, I'm fine with that too, thanks.

BobTurner
01-30-2020, 07:42 PM
I have the Archer nav antenna (which, technically, is a quarter wave over a ground plane) in my -10?s wingtip. Works fine. Of course, I always land 15? right of the center line -:).

Mconner7
01-30-2020, 07:49 PM
I made an Archer knock off using scrap aluminum and it works great for both VOR and LOC. It is in my right wingtip. My com two uses a second ELT antenna in my baggage compartment. RV-10

Pilot135pd
01-30-2020, 07:57 PM
I have the Archer nav antenna (which, technically, is a quarter wave over a ground plane) in my -10?s wingtip. Works fine. Of course, I always land 15? right of the center line -:).

I never land too close to the centerline anyway so if I install one of those antennas at least I'll have an excuse :D

Seriously though, you don't have any issues with the fuselage blocking the signal when you're turning or anything like that? Those are comments from other websites I've read.

Pilot135pd
01-30-2020, 08:01 PM
I made an Archer knock off using scrap aluminum and it works great for both VOR and LOC. It is in my right wingtip. My com two uses a second ELT antenna in my baggage compartment. RV-10

I was going to make a dipole with coax but I've got some aluminum strips I can cut too. Thanks.

BobTurner
01-30-2020, 08:24 PM
I was going to make a dipole with coax but I've got some aluminum strips I can cut too. Thanks.

A dipole won?t fit, won?t work well in the tip, will be oriented incorrectly.
To copy the Archer, make sure you copy the built-in capacitor exactly (area, spacing, and dielectric material). It?s better if you can borrow some ham radio equipment, like an antenna tuner.
I?ve never had an issue with an ils signal, localizer or GS. I have tuned in a distant vor (over 40 nm) and done a 360, and seen it flag when the vor was at 90 deg to the airplane axis, so the signal had to go thru the fuselage. Closer (stronger) signals, no problems noted.
I?ll also say that I?ve seen photos of Archer installations that were unbelievably bad (2 cases). It?s amazing they worked at all. So sometimes negative comments are due to installation errors.

Pilot135pd
01-30-2020, 08:28 PM
Are you using it with one coax and a diplexor to the Localizer and the ILS or just to the Localizer?

GalinHdz
01-30-2020, 08:36 PM
I was thinking about separating them or just plain building 2 new dipoles and installing them in the fiberglass wingtips instead of installing this ugly draggy antenna on the fuse.
Your RV may be fast, but not so fast that parasitic drag from this antenna will noticeably affect your speed. I don't think you are doing +300Ktas. :D

If there's no other choice I'd install it under the pilot seat so it can't easily be seen from outside.
I am assuming you mean on the outside of the airplane under the pilots seat.

:cool:

Pilot135pd
01-30-2020, 08:52 PM
I was going to make a dipole with coax but I've got some aluminum strips I can cut too. Thanks.

If I decide to go with the wingtip installation instead of just mounting it under the plane, I just saw them on Aircraft Spruce for $120 so I might just buy it to make sure it's correct.

Pilot135pd
01-30-2020, 08:53 PM
I am assuming you mean on the outside of the airplane under the pilots seat.

:cool:

Correct, under the pilot seat OUTSIDE of the plane. Seriously ? :D:D:D

Pilot135pd
01-30-2020, 08:55 PM
Your RV may be fast, but not so fast that parasitic drag from this antenna will noticeably affect your speed. I don't think you are doing +300Ktas. :D

Pretty darn close ;)

BobTurner
01-30-2020, 09:07 PM
Are you using it with one coax and a diplexor to the Localizer and the ILS or just to the Localizer?

One coax to an SL30. The SL30 has an internal splitter for the GS receiver.

Pilot135pd
01-30-2020, 09:09 PM
One coax to an SL30. The SL30 has an internal splitter for the GS receiver.

Cool. The VAL has 3 antenna connectors for LOC, ILS, and Marker Beacons.

BobTurner
01-30-2020, 10:05 PM
Cool. The VAL has 3 antenna connectors for LOC, ILS, and Marker Beacons.

If that?s really what it says, VAL needs a new tech writer. It should be something like VOR-LOC, GS, MB.
Of course MB are at 75 MHz, should have its own antenna.

Pilot135pd
01-30-2020, 11:28 PM
If that?s really what it says, VAL needs a new tech writer. It should be something like VOR-LOC, GS, MB.
Of course MB are at 75 MHz, should have its own antenna.

That?s not what it says on the instrument, that?s what I said.

GalinHdz
01-31-2020, 11:17 AM
Correct, under the pilot seat OUTSIDE of the plane. Seriously ? :D:D:D

You never know. :D :D :D

BobTurner
01-31-2020, 01:12 PM
You never know. :D :D :D

Since this thread started with wingtip antennas: I have seen a photo of an Archer antenna that was installed with the radiating element (the actual antenna) riveted to the end rib, with the ground leg hanging free. The owner complained of poor performance.

lr172
01-31-2020, 01:32 PM
Cool. The VAL has 3 antenna connectors for LOC, ILS, and Marker Beacons.

On my two 430 installations (separate loc and gs), i made a homemade gs antenna installed in the cowl. I followed bob turners guidance on this forum, and it works very well. Much cheaper and lower loss than a diplexer

Pilot135pd
01-31-2020, 01:53 PM
Since this thread started with wingtip antennas: I have seen a photo of an Archer antenna that was installed with the radiating element (the actual antenna) riveted to the end rib, with the ground leg hanging free. The owner complained of poor performance.

Wow those antennas are better than they claim then !!

Pilot135pd
01-31-2020, 01:54 PM
On my two 430 installations (separate loc and gs), i made a homemade gs antenna installed in the cowl. I followed bob turners guidance on this forum, and it works very well. Much cheaper and lower loss than a diplexer

Do you have a link to that thread?

GalinHdz
01-31-2020, 05:58 PM
Since this thread started with wingtip antennas: I have seen a photo of an Archer antenna that was installed with the radiating element (the actual antenna) riveted to the end rib, with the ground leg hanging free. The owner complained of poor performance.
I believe you.

How about an owner complaining that his radio didn't have much range. He had a BNC to F adapter on the radio, 30ft of RG59 coax to another BNC to F adapter on the antenna. He told me he got the 2 adapters and 30ft of "Coax" at 1/2 the price of what 30ft of RG400 cable would have cost him. :eek:

lr172
01-31-2020, 10:44 PM
Do you have a link to that thread?

I do not. I found it via search. Search for "DIY glideslope." It's pretty simple, just strip the coax (58, not 59 like Galins buddy) to a specific dimension (found in search - somewhere around 10") and slide the plastic insulated core out through the base of the exposed shielding. Then fold the shielding back over the full coax and run a long piece of shrink tubing over the exposed shield and core to protect it. Mount horizontal to the inside of the fwd cowl area and hold in place with 2" f/g tape and resin. Put a male BNC connector of the end of the coax at the firewall.

Lots of approaches on this and never had a problem picking up the GS signal. I am told the GS is a strong signal and a coat hanger would likely work at 5 miles out.

Larry

BobTurner
02-01-2020, 01:00 AM
I think the dimension is more like 9?.
Another option: just copy the GS antenna high up on the windscreen in a lot of 1970?s era Cessnas.

Pilot135pd
02-01-2020, 11:41 AM
More stuff to research !! Thanks.

Pilot135pd
02-02-2020, 02:16 PM
So I have a few options if I want to use the NAV cat whiskers. The Archer antenna has the ground side of the dipole flat against the rib and the other one pointing out. I could take this one and bend the ground element parallel to the rib and the radiating element keep it as close to the outside contour of the wing tip. I would move the radiating element closer to the side plus I'd bring it further back to get as much angle as I could. I just placed it there so you'd get an idea of what I'm trying to say.

http://i.imgur.com/p37KL3Vl.jpg (https://imgur.com/p37KL3V)

Pilot135pd
02-02-2020, 02:25 PM
Another option below the pedals area but I have a COM antenna and the transponder ant in that area. I also plan to install the ADS-B Out antenna on the other side of the fuse opposite the current transponder antenna. This position is ok because you can't see it with the plane parked unless you bend over. I believe this also would be the easiest way to install it.

http://i.imgur.com/2NojMZtl.jpg (https://imgur.com/2NojMZt)

http://i.imgur.com/L3YDViTl.jpg (https://imgur.com/L3YDViT)

Pilot135pd
02-02-2020, 02:31 PM
The last position I looked at would be to install it on the lower cowling right behind the air filter. I'd have to drill two holes and squeeze the elements together a little bit to get them out the back and squeezing them together changing the pattern too much up to now is my main concern. Any other concerns I'm not seeing?

http://i.imgur.com/RibHjUbl.jpg (https://imgur.com/RibHjUb)

http://i.imgur.com/wYvIFvJl.jpg (https://imgur.com/wYvIFvJ)

http://i.imgur.com/XU3SaCil.jpg (https://imgur.com/XU3SaCi)

GalinHdz
02-02-2020, 02:49 PM
IMHO as long as the comm antenna isn't too close to the VOR/NAV antenna any of those options will work, just one will work slightly better than another. The problem is you may not figure out which works "best" without instaling and flight testing. :cool:

BobTurner
02-02-2020, 03:29 PM
I can’t see the photo in post #25.
You need some care here. The Archer is not a dipole, but a quarter wave over a ground plane. In theory its impedance is half that of a dipole, so if you throw in an existing dipole as you describe and clamp one side to the end rib the impedance will change. Note the Archer has a fancy network to provide a 50 ohm impedance load to the coax.
Likewise, placing the dipole under the airframe so close the large conducting belly is far from optimum.