R

RV8R999

Well Known Member
where have builders decided to locate comm/xdpr/gps antenna?

I've seen the wingtip mounted NAV antenna but since i'm going 100% GPS I don't need that. Not sure about a comm ant in the wing tip since the polarization is opposite of the NAV requiring more vertical space vice horizontal as the NAV does?

thoughts,

Ken
 
Hi Ken, good to see another BD4 guy here, with a '8, no less.

Search the forums for all kinds of antenna location info.

On my 8, I put two bent whips for com on bottom located just aft of the main spar and outboard just inside of sides. I put the tpx on a removable panel just aft of the firewall on the pilot's side and put a small feedthru hole for the cable in the forward floorboard near the FI pump.

For the gps, I located it on a small shelf at the firewall (forward)...seems to work just fine thru the cowl.

All these locations seem to work fine and meet the manf's spacing requirements.

BTW, I sold my BD4 about 8 years ago (parted it out to get max $ and least liability). Unfortunately, the buyer managed to lose control on a landing, totaling the plane.
 
Hi Deene,
I've seen pics of your BD-4 on the BD4.org site and read some of your posts on that forum over the years. Interesting, I also sold my BD-4 as an airframe only with all the good stuff removed and lots of log book entries about how the plane is no longer airworthy and needs to be re-inspected and assembled blah, blah, blah..the new owner is almost ready to fly it again..we'll see.

Anyway...so you access your comm ant through the removable foot wells? Sounds like a good spot.

Thanks for the input!

Ken
 
Ken,

I concur with Deene on the shelf for the GPS antenna under the cowl - works great! A gotcha that some folks run into is mounting this beautiful shelf and then putting the cowl in place to realize that it interferes with getting the top cowl aft hinge pins in place (if you use them) - a typical "plan ahead" issue when doing stuff not in the plans. reception is great in that location, and no one knows its there.

For Comm - go with belly antennas - if you think you'll have two comms, put two down there now, or at least put a dingle one off-center enough to add a second one on the opposite side later. I put one down there, just slightly right of center, and my second Comm antenna in the wing tip. After a LOT of messing around, I have gotten the wingtip antenna to work at about 50 miles with a strong ATIS, but it gets blasted out if I turn on my HID landing lights. If I had put the belly Comm antenna off-center, it would be a piece of cake to just put another one on the other side, but at this point, I'd have to do some patching and painting, so I live with what I have.

As Deene said - lots of threads on antennas in the archives!

Paul
 
HI PAUL,

PLANNING MY ANTENNA PLACEMENT NOW TOO FOR MY 8 WITH TWO COM RADIOS. MY PLAN IS TO PLACE THE ANTENNAS JUST AFT OF THE AILERON TUBE BELOW PASSENGER FOOTWELLS ONE ON EACH SIDE IS IT OK TO HAVE TWO COM ANTENNAS THAT CLOSE TOGETHER? WOULD RATHER HAVE THEM ON THE BELLY THAN IN WING TIP.
 
For the gps, I located it on a small shelf at the firewall (forward)...seems to work just fine thru the cowl.

All these locations seem to work fine and meet the manf's spacing requirements.
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Are there any heat issues with the GPS antenna located fwd of the firewall, I had planned on mounting mine aft of the firewall on top of fuselage but would rather have it hidden.

I had a hidden wingtip com antenna and had to change to a conventional antenna on my RV-6A. The reception was too poor.

Jay Erickson, RV-7A finishing, RV-6A complete
 
Hi Jay...

...my buddy has a -4 with both the XM wx receiver and the GPS antenna side by side under the top cowl on a shelf. The heat from the case and cylinders is trapped by the baffling and only a little heat comes off the rear of the engine when you park. Guys often open the oil filler door to relieve some of the heat but he doesn't. Firewall mounts have worked well for a lot of guys with differing paints as well.

Regards,
 
I agree with the off center on the belly for Comm. Here is where I have mine mounted. All get great reception. The GPS antennas where painted black (painted over the do not paint markings) with flat black Krylon. No issues.
rvantennas.jpg
 
I'm going with my GPS and Xm ant on a shelf in the left wing tip. I'm not worried about heat issues under the cowl but my past maintenance experience with my other plane tells me to keep the firewall as clean as possible. Inevitably some bolt, nut, hose, something will need to be tightened, removed, replaced..etc... and that shelf on the firewall will be in the way..I just know it :)

Thanks for all the replies!

Mounting the Emp this weekend....first time she'll look like an airplane and not a canoe!

Regards,
Ken
 
RV8MW said:
IS IT OK TO HAVE TWO COM ANTENNAS THAT CLOSE TOGETHER? WOULD RATHER HAVE THEM ON THE BELLY THAN IN WING TIP.
Click to expand...

I think that minimum spacing is 18 inches for Comm, and you should be able to get that on the belly of the -8. I'm sure I'll get corrrected if I'm wrong!;)
 
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