GTN GPS Antenna just aft of the canopy rail?

[inktomi]

Hello!

I'm (still) waiting on backordered parts, so I don't have the ability to actually roll my canopy frame on the mounts. I'm finishing up the last bit of wiring - antennas!

Would this location conflict with the frame at all as it moves? Or is it safe to place the antenna here?



I can't place it under the cowling due to plans on making a carbon fiber cowling down the road. As this needs to talk to satellites, it seems like this might be the next best place for it - but would it conflict at all with the movement of the canopy?

Thanks folks!

 

[Jonnyb]

Is that down by the tail?
Most people put it further up and to one side of the canopy rail, just behind the rear seat.
Down there it may well interfere with the canopy skirt, and the opening and closing of it. Also the canopy comes off by sliding off the rail at the rear. It might well interfere with that process.

 

[Majorpayne317641]

I put mine in front of the wind screen where the front baggage is and it works perfect.

 

[ATC_RV8OR]

RV8 Comm Antenna Locations

Now that Google searches no longer return VAF search results I'm having a hard time finding what I'm looking for. I'm sure this has been discussed, but I am trying to find the best location for dual comm antennas on the -8. Both will be Garmin comms with CI-122 antennas. All I see in the G3X and...

vansairforce.net

See post above, someone did it.
Consider putting it behind the rear passenger under the canopy. It’s in full view when the canopy is closed and the connector will be easier to access than all the way back in the tail

 

[ATC_RV8OR]

RV8 Comm Antenna Locations

Now that Google searches no longer return VAF search results I'm having a hard time finding what I'm looking for. I'm sure this has been discussed, but I am trying to find the best location for dual comm antennas on the -8. Both will be Garmin comms with CI-122 antennas. All I see in the G3X and...

vansairforce.net

See post above, someone did it.
Consider putting it behind the rear passenger under. It in full view when the canopy is closed and the connector will be easier to access than all the way back in the tail

Not mine but this is common

 

[RV7 To Go]

That's where I put mine. Clears fine. You could also put it farther forward offset from the rail like many do, as above.

 

[RV8Squaz]

I would not place it in the location you indicated. There is a possibility of it interfering with the canopy. But it’s unknown until you’ve finished the canopy, skirt and all. The aft end of the skirt gets within a few inches of the forward part of the empennage fairing. So vertical clearance between the bottom of the skirt and the antenna will be the issue.

 

[Carl Froehlich]

Here. Simple, works well, does not interfere with the canopy and meets the Garmin “at least this long but no longer than that” rules for the coax run.

Carl

 

[inktomi]

Awesome! Thank you thank you!

For the folks who have put it alongside the rail - that seems like a great location - what clearance is required between it and the rail to allow the rollers and such? It looks like it can get pretty close based on @Carl Froehlich's photo? Half an inch?

 

[Carl Froehlich]

Awesome! Thank you thank you!

For the folks who have put it alongside the rail - that seems like a great location - what clearance is required between it and the rail to allow the rollers and such? It looks like it can get pretty close based on @Carl Froehlich's photo? Half an inch?

Easy way, take the nylon canopy frame slide that rides the rail, measure the distance the slide extends beyond the rail (as in left/right), double that distance as a gravy factor and that will be the edge of your GPS antenna.

Note - the antenna is set back a little from the forward rail end that goes into the slide pocket. Going into the pocket the frame gets much closer to the top of the fuselage.

This is all easy to do once you have the rail and frame in place. No need to do this ahead of that.

Carl

 

[RV-9erA]

That's where I put mine, too!

 

[inktomi]

Vans did not ship me the bag of parts that includes all the rollers, slides, etc - everything you need to actually put the frame on the plane. Sorry, it's been backordered since October, with not a peep of information from Vans in the meantime. I'm trying to get stuff done in the meantime.

 

[Scott Chastain]

Matt,

Please be patient on this one and wait for your canopy slide to arrive. Drilling those holes on your turtledeck is a one-shot attempt unless you don't mind having to create patches if you mess it up. Also, I see you plan on painting the slide rail because it is already primed. Don't paint or prime that rail! Polish it instead using the same compounds that bare metal builders use to polish their aluminum skins. That rail needs to be super slick, and paint is only going to interfere with the slickness of the slider block, especially when the surface starts to chip and peel---which it most certainly will under the friction of the canopy slide.

The reason I advise you to simply wait for your parts is because of the process involved. The curvature of the turtledeck requires that you match it to the flat bottom of the antenna with a slurry shim. Because of that process, being absolutely certain of your placement is a must. Here's what I'm referring to:

 

[inktomi]

I appreciate the info, and I can certainly wait.

I didn't prime the rail for any reason other than I prime everything unless the directions tell me not to.

I can certainly try to strip it off. The Azko primer is though as nails, but a maroon pad on a grinding wheel should work.

 

[Scott Chastain]

A citrus-based paint stripper will make easy work of it. Paint it on and let it sit overnight. You will wake up to a strip of aluminum with a green skin bubbled cleanly off the rail. Then polish it as recommended above with Nuvite or similar compound.

All the best!

 

[chrispratt]

Hello!

I'm (still) waiting on backordered parts, so I don't have the ability to actually roll my canopy frame on the mounts. I'm finishing up the last bit of wiring - antennas!

Would this location conflict with the frame at all as it moves? Or is it safe to place the antenna here?

View attachment 109071View attachment 109072

I can't place it under the cowling due to plans on making a carbon fiber cowling down the road. As this needs to talk to satellites, it seems like this might be the next best place for it - but would it conflict at all with the movement of the canopy?

Thanks folks!

All good replies above. Here are some additional pics of where mine is mounted including also a pic of the canopy at full rear extension. Like the others, I don't think placing the antenna behind the rail will work. Just behind the rear passenger area seems to work and be readily accessible. If there is room on top of the instrument panel that could make for a shorter cable run.

 

[inktomi]

I think there is a minimum cable length, and it would be nice to not have it in the view always, but centered above the panel would otherwise work.

I will goop the track up with citrus stripper today and once I get the canopy on I'll probably put it right where everyone has been suggesting.

 

[rcharris]

A slurry is one way to do it. I have been experimenting with a 3D scanner and scanned the curvature of the back deck and 3D printed an ASA shim. Fits great. Clearance is less than 1/2 inch but that’s ok. The STEP file for the antennas can be found in the Garmin website.

 

[inktomi]

I was also thinking about 3d printing it... It would be an excuse to buy a 3d scanner, which would be fun in general to get the proper curve for the fuselage.

 

[Carl Froehlich]

A slurry is one way to do it. I have been experimenting with a 3D scanner and scanned the curvature of the back deck and 3D printed an ASA shim. Fits great. Clearance is less than 1/2 inch but that’s ok. The STEP file for the antennas can be found in the Garmin website.




View attachment 109540

Nice work, but I suggest:
- I’d be more concerned with the reduce clearance than making the Garmin GPS antenna level. I can report that the location I used and just mounted the antenna on the skin (post #8) works well.
- Note that Garmin requires at least a 9” spacing to another GPS antenna.
- I mount the Dynon GPS antenna on the glare shield. This antenna/receiver puck is less touchy on placement than the Garmin. I put the Dynon puck on the glare shield on all four builds - always works and locks up faster than the Garmin GTN-650. Cover it with a dark cloth to eliminate glare on the windshield.
- Do not mount the Garmin GPS antenna on the glare shield as it is susceptible to RFI if mounted there (as in all the satellites go away when you transmit on the GTN-650 radio).

Carl

 

[Steve Watkins]

Mine is mounted right where you have your finger in the original post. Just behind the end of the canopy rail. It doesn't interfere with the canopy skirt. The skirt goes right over the top of it with plenty of clearance. Not saying it is the best place to mount it, only that it works fine.

 

[rcharris]

Nice work, but I suggest:
- I’d be more concerned with the reduce clearance than making the Garmin GPS antenna level. I can report that the location I used and just mounted the antenna on the skin (post #8) works well.
- Note that Garmin requires at least a 9” spacing to another GPS antenna.
- I mount the Dynon GPS antenna on the glare shield. This antenna/receiver puck is less touchy on placement than the Garmin. I put the Dynon puck on the glare shield on all four builds - always works and locks up faster than the Garmin GTN-650. Cover it with a dark cloth to eliminate glare on the windshield.
- Do not mount the Garmin GPS antenna on the glare shield as it is susceptible to RFI if mounted there (as in all the satellites go away when you transmit on the GTN-650 radio).

Carl

The mounting instructions for the Garmin GA series call out minimum clearance for VHF GPS, and also for other antenna which may emit harmonic interference at the L1 frequency of 1575.42 MHz. I checked with Dynon and, as expected, though it is a powered GPS antenna, there should not be any concerns as it's inherently not an emitter.