WAAS Antenna GPS Location

carl nank · #1 07-18-2009, 07:17 AM

I am installing the GPS antenna for my GNS430W. (I HAVE THE TIP UP CANOPY ON A RV7-A). The install manual says the the #1 item regarding the WAAS antenna is to place it level (in flight) for proper operation. It aso states that behind the canopy is the best place for location.

I have a RV7A and I have an 8 degree up slope behind my tip up canopy. The only level place I can find on the airplane is on the bottom fuselage and that will not work.

I have seen some GPS antenna's mounted behind the tip up canopies. My question is, do you have any problems with the WASS in that position or are you using some kind of structure to make the antenna level?

I appreciate your help.

Rick_A · #2 07-18-2009, 07:48 AM

I've got my GNS480 WAAS antenna mounted behind my slider canopy. It works just fine. I never even thought to measure the slope of fuselage. I think 8 deg off level is a non-issue.

breister · #3 07-20-2009, 07:25 AM

Aim it up - that's where the satellites are...

mburch · #4 07-20-2009, 07:27 AM

Quote:

Originally Posted by breister

Aim it up - that's where the satellites are...

...but depending on where you are, the WAAS satellites might be closer to the horizon!

mcb

Capflyer · #5 07-20-2009, 08:33 AM

I fabricated a small shelf and mounted it to the firewall under the cowling. Many others have also done this and it works perfectly. The only time I loose my GPS signal on the GNS480 is when I'm upside down.

carl nank · #6 07-23-2009, 01:45 PM

...but depending on where you are, the WAAS satellites might be closer to the horizon!

That is the problem that I am considering. Has anyone mounted the GPS behind the canopy and had any problem with WAAS?

fstringham7a · #7 07-23-2009, 02:07 PM

Quote:

Originally Posted by carl nank

...but depending on where you are, the WAAS satellites might be closer to the horizon!

That is the problem that I am considering. Has anyone mounted the GPS behind the canopy and had any problem with WAAS?

I have the tip up with the WAAS antenna on the turtle deck just aft of the
plexie over the bagage area....WORKS FINE

You will note it in this moving day picture. I placed it on the triangular gussett.

Frank @ 1L8 ...RV7A... Phase 1

Martin Sutter · #8 07-23-2009, 02:15 PM

The GNS430 WAAS antenna in my 7A with tip-up is mounted under the rear window. I made a bracket that holds it right under the glass next to the roll bar for and aft brace, about 1" forward of the window's aft edge. It has worked flawlessly there for the last two years including GPS approaches.

My friend with a 7A had his mounted under the cowl, ahead of the fire wall. It worked fine there until the airplane got painted and he started seeing RAIM warnings while shooting approaches. Moving it aft under the back window cured the problem. Evidently there was something in the paint that blocked the signal.

Martin Sutter
building and flying RV's since 1988
EAA tech counselor

McFly · #9 07-23-2009, 03:37 PM

I mounted the antenna of my Lowrance 2000 on top of the glare shield, which is a relatively flat area.

I don?t have any experience with the Garmin units but my unit does not seem to be very particular about antenna placement. If I am in the air, I get a WAAS signal. Good luck.

Hugh