Garmin 430W Antenna recommendations...?

[Jon Clements]

I am installing a GNS430w in my RV-7.

I have a Comant VHF underbelly Antenna for the COM 1 so that is simple. Com 2 (SL40) will be connected to a top mounted Comant VHF Antenna

I have already installed a Bob Archer wingtip Antenna so I plan to use it.

Can anyone advise if I will suffer any noticeable performance reduction if I run the Archer Antenna through a splitter/diplexer to deal with my NAV and GS signal inputs for the GNS 430W?

Has anyone put Bob Archer antennas in both wingtips and connected one to the NAV input connector and the other to the GS input connector - would this result in better performance (the cost is about the same as installing a splitter).

Any other suggestions (I want to avoid installing cats whiskers if possible).

Would be interested in knowing what some of you (with 430's) have done for Antennas and how they perform?

Thanks in advance.

Cheers,

JON.

 

[Kahuna]

I assume you are asking if the archer VOR antenna can be run through a diplexer that splits the vor nav input into a vor and gs output to the 430.
The answer is yes.

As for performance reduction, I could not say since I have only had it this one way as described above. Ive never experienced any performance problems with this setup and I use both the nav and gs often.
Best,

 

[Ironflight]

Jon,

I struggled with a degrading Bob Archer (style) antenna for awhile, and after replacing it with a REAL Bob Archer, things got better, but due to the arrangement and quantity of wiring in my wing tip, I never got the kind of GS reception I wanted having it split through a diplexer. I finally ran the Bob Archer to the VOR receiver, and made my own 16" GS antenna (strip 16" of shield off the core of a piece of coax, mount it in your cowl or up to the windshield bow or roll bar, and run the other end to a BNC connector to plug in to your GS antenna input on the 430). Now I have great VOR/LOC and GS reception. I wish I'd gone that route a lot earlier!

The diplexer might work just great for you, but if it doesn't, the separate GS antenna is extremely easy to build.

Paul

 

[apatti]

Paul,
You just saved me over a $100 and some lost db's! When mounting the GS antenna in the cowling, what is the best orientation and location. I don't know if GS transmissions are horizontally or vertically polarized.

Also, is the GS antenna center-fed (dipole)? Or, end fed?

Thanks,

 

[RVG8tor]

Also interested

I will plan the Bob Archer in the wing, but am very interested in GS antenna idea. Please pass along any other specifics, I and I am sure others would appreciate the help.

Cheers

 

[ddurakovich]

I am installing a GNS430w in my RV-7.

I have an Comant VHF underbelly Antenna for the COM so that is simple. Com 2 (SL40) will be connected to a top mounted Comant VHF Antenna


JON.

I ralize that you didn't ask, however.......

You might consider running COMM 1 off of the top mounted antenna, and the SL-40 to the belly. There have been instances where the belly mounted antennas have been problematic, especially on the ground talking to the tower.

I know that many people never have a problem with this arrangement, but some do, so it becomes a matter of which COMM do you want to be the MOST reliable, 1 or 2?

 

[dhall_polo]

diplexer

I have single Archer antenna for vor/loc/gs, run to 430W through the diplexer that Kahuna mentions. No issues.

In same wingtip, there's also marker beacon antenna, which is just a coax with the 40" of braiding stripped.

Com is vertically polarized. VOR/LOC/GS is horizontally polarized.

 

[sjjonesnz]

I have two CI-122 antenna for SL30 (Com1) and GNS430W (Com2) mounted under the fuselage just forward of the rudder pedals, the CI-105 transponder antenna is under the fuselage behind the baggage area, the Garmin 013-00235-00 GPS 'puck' is on top of the fuselage just aft of the cockpit, and the Comant CI-215 VOR/GS/LOC antenna is on the tail connected to a CI-5120 splitter which has 1 tail going to SL30 (Nav1), the other going to a CI-507 diplexor with 1 tail each going to P4005 and P4007 on the GNS430W (Nav2).

Not flying yet so don't know if it actually works....

 

[Ironflight]

Tony and Mike,

Since you're both buildings -8's, you might like my extremely simple solution to GS antenna placement. Drill a Coax-sized hole in the glare shield next to (and inside) the windshield. Take a piece of Coax about 3' long, put a BNC connector on one end, and strip the shield braid off the other end leaving 16" of the core insulation exposed. Use some black heat shrink to cover the exposed core, just for appearances sake. Now run it through the hole in the glare shield, leaving enough inside to connect to the back of your radio. Run the "antenna" end back along the edge of the windshield (drill your hole as far aft as you can), and then up the front of the roll-bar. Tuck it back in the crevice between the windshield and the roll bar - it will go up and about to the center of the windshield - but you'll never see it because it will be under the fiberglass.

That's the magic formula. I've gotten G/S reception at close to 30 miles with that rig.

Of course, you may never have a problem with the Archer antenna, but if you do, this is a great way to buy back a dB or so....

Paul

 

[Jon Clements]

Thanks all - just the answers i needed.....

I ralize that you didn't ask, however.......

You might consider running COMM 1 off of the top mounted antenna, and the SL-40 to the belly. There have been instances where the belly mounted antennas have been problematic, especially on the ground talking to the tower.

I know that many people never have a problem with this arrangement, but some do, so it becomes a matter of which COMM do you want to be the MOST reliable, 1 or 2?

Dave / Paul etc....

Thanks - figure I'll give the Diplexer a shot and see how that performs....I've got a tip up canopy so the GS antenna would have to lie flat under the front of the plexi on top of the glareshield (not sure how that would perform compared to your set-up Paul?).

In regards to Com 1 to underbelly aerial - I figured that when I am in the air i would get the best range/performance from the belly aerial rather than the top mounted aerial. Com 2 was going to Top for this purpose. The comment is valid. I have a private airfield which is approx 7nM from a control tower and we are inside CTA. When on the ground we can generally get the tower on top mounted aerials (just) but underbelly aerials don't cut it.

Thanks for your feedback (so promptly).

Cheers

JON.