Antenna placement

[Area 51%]

Have decided to place the comm antenna on the belly just ahead of the spar box. Just no good flat spot to attach it on the turtledeck.

Is there any reason it can't be offset to one side or the other to keep it out of the exhaust stream?

[GordonTurner]

Two ideas:

It should be well clear of the landing gear, but also have good ground clearance.

Two, I wouldn’t be happy about putting a radiating element next to my nuts.

Gordon

[Area 51%]

It's hard to keep it out of the landing gear's shadow because of the angle of the legs. I've got a bent-wire antenna, and unless the gear fail to extend, there is plenty of clearance.

I'm OK with the radiation. In fact, had I thought of this 35 years ago, I probably could have saved enough in child support to build an RV.

If I stick a hot dog on the antenna, do you think it will be done by the time I land?

[inventor]

Two ideas:

It should be well clear of the landing gear, but also have good ground clearance.

Two, I wouldn’t be happy about putting a radiating element next to my nuts.

Gordon

My chemistry professor in college had a radioactive rock that he wrapped in aluminum foil and kept it on a shelf about head level next to his desk. One day we checked it with a geiger counter and found the foil did nothing to stop the radiation. Maybe that accounts for his unusual teaching style.

Richard

[Area 51%]

Well that settles that. I can no longer afford to lose any of my remaining brain tissue, so the antenna is definitely going down by my feet, closer to the parts I don't use very much anymore.

[N190YX]

I have had a belly mounted com antenna on my Debonair for 37 years. It is about 3-4' behind a tailpipe. This antenna has a 90 degree bend and extends aft. It is blocked by large main gear doors and wheels/tires when the gear is down in flight and of course during ground operations. I have never had any problem communicating with that antenna while on the ground or in the air. Never. I do not think the landing gear on a Sonex/Waiex would interfere with communications through a belly mounted antenna mounted anywhere on the belly. I never thought about RF penetrating a human body either from the belly or from a roof mounted com antenna (two coms in the Debonair, one com antenna on the top, one on the bottom). But how many seconds do we actually transmit during a flight? I would imagine not many. The other thing is, the top of the fuselage is the worst place to install any antenna, aerodynamics wise, as that is where the air is moving by at the highest velocity, so this location gives the most drag. I intend to mount a belly com antenna on the Waiex, now thinking about forward or aft of directly below the seats, considering the RF issue with seats mounted so close to the belly. Related to mounting anything on top of the fuselage, planning to mount GPS antenna(s) somewhere inside, on the glare shield, to the bottom of the aft end of the windshield, or ? I'll be seeking advice when that time comes. The transponder and ADS-B out antennas need to be mounted on the belly. There are ADS-B installations which require two antennas, one on the belly and one on top. I do not have that kind of installation in my Deb (Garmin GDL88) and am not planning one for the Waiex. In writing this, thinking about that the transponder and ADS-B out transmit continuously, those antennas really need to not be under the seats! It may be necessary to mount antennas towards the sides of the belly to obtain required distance between them. Mounting them in the exhaust stream has not been a problem in my experience with a com antenna mounted in the exhaust stream behind a tail pipe. That com antenna tends to get white with lead deposits, I only clean it with Stoddard Solvent.

[racaldwell]

For GPS antenae location, I made a mount under the glareshield. I have a large access panel I made for access behind the panel from above. The cover is made of S-glass/epoxy and the two GPS antenae are mounted just under that cover.

The ELT antenae is located in the cockpit next to the passenger's elbow.

I'll mount the comm and transponder antenae on the bottom of the fuselage like I did on my RV-6.

Rick Caldwell
Xenos 0057