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RV-10 antenna placement?

Mike D

Well Known Member
It is time for me to start installing the antennas. So, where do I place them?

For comm, I have two CI122 bent whip antennas for the rv-10. I strongly prefer the bottom for looks, but I'm ever so slightly worried about performance. On my -6a, I have two placed under the seats as far apart as possible. This works okay but may not be the best. They seem to have an issue with transmit/receive exactly forward. 2-3-degrees off forward and they are fine.

For GPS, I plan on either overhead between the doors (mounted inside the cabin) or just in front of the firewall and just below the top cowling. Under the cowling works okay in my -6a. But slightly concerned with heat. I have had a few unexplained loss of signal in the -6a, but I doubt this was due to heat as it is random. Sometimes just after startup. But this may be due to the 2-GPS and 1 XM antenna all being mounted very close to each other.

Transponder and ADS-B??? Transponder is most likely under the tunnel just in front of the spar. Easy to route the cable and still a short run of cable. How close can the ADS-B be?

VOR/GS will most likely be the Bob Archer type in the wing tips. Other option is cat whiskers on the top of the vertical stab.

So, what say everyone? Any reports of performance issue would be great.
 
what I did.

I have dual bent whips on the fuse bottom--------no issues. They are in trail, not side-by-side.

VOR below the tail-------I would have put it on the top of the stab, but that was too much work on a finished plane, thus below.

Xpnder---bottom by the spar like you said, ADSB says minimum 5' separation as I recall.

I have all satellite antennas on the glare shield.

ELT is horizontal on the baggage bulkhead, pointed forward, up against the fiberglass top.
 
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Mike,
One thing you did not state is weather this is to be an IFR certified system, or strictly VFR. Let me assume it is IFR.

If you are using an Audio Panel that allows split com use. That is... Pilot and Co-pilot can use separate radios at the same time. You will want to mount one comm antenna on the top and one on the bottom to max out the isolation. BTW, this is specified in the PS engineering IM. In addition to the benefit of antenna isolation, an antenna on top will work far better for ground communication than one hidden in the shadow of the aircraft.

I personally have the Bob Archer wingtip antennas, one in each wing tip. He recently passed away, so I am not sure of the availability of his products at this point. They work great for me for the Nav and ILS. I also have a home made marker beacon antenna in the wing tip.

The Garmin IM will suggest where you will want to locate your IFR GPS antenna. I don't feel that putting it inside the cabin with fiberglass in between it and and sky would be as good as mounting per the Garmin IM for the 430W or GTN650, which is on top of the fuselage. Last time I looked the antenna puck has a note on it stating not to apply paint to it's surface, much less paint and glass. I have mine mounted between the doors in the most flat location possible. I also have the G3X GPS antenna puck located on the top of the fuselage about 18 inches aft of the 430W antenna.

My transponder antenna is under the pilot seat and my ADS-B antenna is two bulkheads rear of the baggage bulkhead on the right side of the fuse.

For me, everything plays well in these locations.

Something to be cautious about, sometimes when GPS antennas fail they can take out an adjacent antenna. The reason.... most all GPS antennas have a built in LNA (Low Noise Amplifier), sometimes when amplifiers fail they turn into oscillators (transmitters), and can cause havoc with the reception of the very weak signal from the GPS satellites by interfering with a co-located secondary GPS puck. Putting them right next to each other should be avoided for this reason.
 
It is time for me to start installing the antennas. So, where do I place them?

For comm, I have two CI122 bent whip antennas for the rv-10. I strongly prefer the bottom for looks, but I'm ever so slightly worried about performance. On my -6a, I have two placed under the seats as far apart as possible. This works okay but may not be the best. They seem to have an issue with transmit/receive exactly forward. 2-3-degrees off forward and they are fine..

That's where mine are and work just fine. I've not experienced any issues on the ground.

For GPS, I plan on either overhead between the doors (mounted inside the cabin) or just in front of the firewall and just below the top cowling. Under the cowling works okay in my -6a. But slightly concerned with heat. I have had a few unexplained loss of signal in the -6a, but I doubt this was due to heat as it is random. Sometimes just after startup. But this may be due to the 2-GPS and 1 XM antenna all being mounted very close to each other..

GPS antenna can cause interference. You should separate them per the manufacturer specs. I seem to recall that Garmin recommends three feet, but check the installation manual and don't trust my memory.

The concern I would have in mounting them on the cabin is two fold. The first is to ensure that you have an appropriate ground plane. It's possible, but it's a lot of work. The second is to hide all the connections. You would have to have an overhead console to hide the wiring. I mounted my GA-25 and RAMI (for ADSB) just behind the baggage bulkhead.

Transponder and ADS-B??? Transponder is most likely under the tunnel just in front of the spar. Easy to route the cable and still a short run of cable. How close can the ADS-B be?.

Following the distance recommended by both your transponder and ADS-B vendor. I seem to recall for Navworx and GTX-327 was ten feet, but my memory could be wrong.

VOR/GS will most likely be the Bob Archer type in the wing tips. Other option is cat whiskers on the top of the vertical stab.

So, what say everyone? Any reports of performance issue would be great.

I mounted mine underneath the tail pointed aft. The ends are protected by the horizontal. I personally prefer the cat whiskers over the Bob Archer type. I believe that the cat whiskers gives me better range.
 
To reinforce Bill's comments on comm antenna location. With a pair of belly mounted bent whips, there are some airports where you won't be able to be heard when transmitting on the ground. I used to be based at one of these and heard of a couple others. Yes, you can always pull out your cell phone... I opted to put one top and the other this time (second RV-10).

Bob
 
My antenna placement: 1 bent whip comm on bottom, 1 angled fiberglass comm on top, 1 Garmin GTN 650 GPS antenna on top, 1 ELT on top, 1 VOR cat whisker's on top of VS, 1 ADS-B blade antenna on bottom, 1 blade transponder on bottom, 3 small GPS antenna's on shelf on the forward side of the firewall under the top cowling. I originally had a MB antenna in the wing tip but removed it as I decided not to install a MB. Read up and follow the manufactures recommendations and directions for mounting, isolation distances, and ground plane requirements and you'll be OK. I installed several of my antenna's after I obtained my avionics because of this.
 
My two cents.
Com: one on top, one on bottom is best. Placing both on bottom is a compromise between the antennas being too close to each other, and not having an adequate ground plane out to one side. That being said, many have placed 2 on bottom. I have one on bottom, under the right rear seat but close to the center line, and only once in a while do I have to turn the airplane when on the ground to talk to the tower. I have been in a 10 with two com's on bottom, he seemed to have a harder time when on the ground. I have an Archer clone for #2 com in a wingtip. It is not as good as the whip but not too bad either. But many have reported dissatisfaction. I suspect it is extremely sensitive to installation.
Nav: I have the Archer in a wing tip, may not be quite as good as cat whiskers for VORs a long ways away, but it has never failed on an ILS (LOC and GS).
GPS: mine is just behind the baggage wall, on top. Trouble with cabin top between the doors is this is an area of high speed air, might cost an extra 1/4 knot!
Transponder: blade, under the pilot's seat.
ADSB-in: antennas glued to the front door posts (Skyradar). no ADSB-out yet.
 
The GPS works great in a console between the doors. So does a copper tape VOR on the inside of the ceiling.
 
Locations

This is what I did and why:

Coms: I put both coms on the bottom and they are under the rear passengers seats as far apart as I could get them. I have only had one or maybe two airports that had a hard time hearing me on the ground (only one had me taxi to a different location before calling), where the antenna on top would have been better. I think my next RV-10 will have the fiberglass antenna on the top.

Transponder: The transponder has a minimun distance from the coms because of the power it puts out. I also wanted to keep it away from the occupants due its high power/radiation. Therefore, it is located behind the baggage compartment, about where the battery is located.

ADS-B: To keep this one away from everything I put it just in front of the rear tie down. I can reach down, through the lightning holes by the vertical stab to install and maintain it.

VOR/ILS: I have the Bob Archer wing tip antenna. I plan on putting an antenna on top of the vertical stab someday. I have flown with other RV-10's with a more traditional antenna and they have can receive VOR's farther away than I can. The Bob Archer antenna works great knowing that most of the time GPS is used and ILS/VOR approaches work great with Bob Archer.
By making to slits in the vertical stab, the VOR antenna sits perfect up there.

I also have an transponder type antenna for my traffic scope. It is located in front of the COM antennas.

I have three GPS antennas on the top. One if for the Garmin 430, one for the Chelton and the ADS-B is under the vertical stab fairing.

Here are a couple of pictures. The first two do not have the ADS-B antenna.

IMG_6514-XL.jpg


oskosh%20day%204%20%28258%29-XL.jpg


This one shows the ADS-B antenna.
IMG_2743-XL.jpg
 
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Dynon's SkyView installation manual says: The SV-ADSB-470 antenna should not be installed within 2 feet (24 inches) of the transponder antenna.
 
Thanks for all the reply's!!! Thanks for the Photos.

I will install the comm antennas under the rear seats. So I now need to install some reinforcements and access panels for these.
The transponder will go just behind the fuel pump/filter in the tunnel. So I need a reinforcement here too.

This will be IFR, so I am leaning toward the cat whiskers on the vertical stabilizer. But I do like the hidden Bob Archer antennas.

ELT is already under the fiberglass tail fairing.

This leaves the GPS and ADS-B antennas. But good thing they can be installed later. I might install a reinforcement/nut plates in the tail cone for the ADS-B but not drill the hole for the connector yet.

This will get me through the interior paint and most of the wiring.

Input still welcome. But that is the plan for now.

Thanks all!!
 
The transponder will go just behind the fuel pump/filter in the tunnel. So I need a reinforcement here too.

I did not put a reinforcement in for the xpnder antenna------200+ hours and no problem. That area is pretty stiff already, with the tunnel sides there.
 
I will install the comm antennas under the rear seats. So I now need to install some reinforcements and access panels for these.
The transponder will go just behind the fuel pump/filter in the tunnel. So I need a reinforcement here too.

This will be IFR, so I am leaning toward the cat whiskers on the vertical stabilizer. But I do like the hidden Bob Archer antennas.

ELT is already under the fiberglass tail fairing.

This leaves the GPS and ADS-B antennas. But good thing they can be installed later. I might install a reinforcement/nut plates in the tail cone for the ADS-B but not drill the hole for the connector yet.

Input still welcome. But that is the plan for now.
!
Lot's of good advice all around.

I would not recommend a Bob Archer Comm antenna - just not good enough even for a 'backup'.

I do recommend Bob Archer Nav antennas. They work but not as well as a normal external installation but so what? I've been flying a lot of IFR and practically speaking, VOR Nav is yesterday. Localizer works just fine.

Both of my Comms are underneath but staggered. On the very few occasions where there as some problem with ground comm, switching radios worked. Don't know if the the stagger helped or not.

I have been convinced that doing an exemplar, by the book placement and install of the WAAS antenna makes sense. That is, mount it externally on the top canopy, Don't shorten the cable, etc. That is and will be your primary navigation antenna for the foreseeable future, treat it accordingly. Which is not to say it won't work just fine hidden somewhere under some RF transparent material. I have 3 or 4 or 5 other GPS units and antennas scattered around the plane and they all work flawlessly as well.

Good luck
 
Good Timing?

I'm about to start my tail cone, is this a good time to consider antenna placement, or not worry about it till later.
 
Lot's of good advice all around.

I would not recommend a Bob Archer Comm antenna - just not good enough even for a 'backup'.

I do recommend Bob Archer Nav antennas. They work but not as well as a normal external installation but so what? I've been flying a lot of IFR and practically speaking, VOR Nav is yesterday. Localizer works just fine.
I agree completely on the Bob Archer COM. The NAV works great. I put the Coms under the pilot and copilot seats. Transponder in the forward tunnel. Gps antennas on a shelf under the cowl.
 
2023 RV10 antenna placement IFR

Okay everyone so I am debating my placement for my antennas and I think I wll be going with this setup:

My Garmin GPS antennas next to each other of FF shelf 6" separated side by side
Com1 just aft of canopy top enough for 18" ground place
Com 2 on belly under pax seat centered
ELT- bellow just aft of firewall
Xponder-belly mounted tailcone rear of airplane

Thoughts everyone

I was also thining of adding the GHA15 but if I add that under the tunnel I will have to relocate the ELT?????

I am about to start the fuse section so any assistance will be greatly appreciated:_)
 
GPS antenna location

Okay everyone so I am debating my placement for my antennas and I think I wll be going with this setup:

My Garmin GPS antennas next to each other of FF shelf 6" separated side by side

I am about to start the fuse section so any assistance will be greatly appreciated:_)

I believe Garmin recommends for GPS antennas placement a min of 12" center to center and if necessary 9" CTC. Stein states 6" but does not specify CTC measurement. That said I did not follow Garmin's recommendations and they seem to perform well. (Easy to check in flight signal strengths various weather conditions)
 
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I'm a fan of the COMDAT CI 2580-200 antenna (Com/GPS combo) on top of the fuselage, kill 2 birds with one stone and no more antenna blocking or crosstalk from side-side belly mounted antennas. I hate FWF mounted antennas.
Keep xpdr antenna cable run as short as possible.
 
I'm a fan of the COMDAT CI 2580-200 antenna (Com/GPS combo) on top of the fuselage, kill 2 birds with one stone and no more antenna blocking or crosstalk from side-side belly mounted antennas. I hate FWF mounted antennas.
Keep xpdr antenna cable run as short as possible.

I did this as well. That COMDAT antenna is great.
I also bought a old non WAAS COMDAT blade antenna from somewhere here on VAF super cheap. They also crop up on eBay occasionally. Its on the belly and only used for Com2. Marginal gains and all that, but getting rid of stuff poking out of the airframe (especially odd shaped and rod antennas) can only help.
Split com works a treat. No issues getting coms on the ground anywhere either.
I had belly mounted dual antennas on my RV7 and that's a poor setup IMHO
 
I was looking at the COMANT COMDAT VHF / GPS WAAS ANTENNA CI 2580 and think I might go this route. This will replace the CI-122 and both GA35 and GA57?
 
Okay everyone so I am debating my placement for my antennas and I think I wll be going with this setup:

ELT- bellow just aft of firewall

I was also thining of adding the GHA15 but if I add that under the tunnel I will have to relocate the ELT?????

I am about to start the fuse section so any assistance will be greatly appreciated:_)

ELT on the belly is pretty unconventional, and won't be able to send to satellites in flight (think on your way down after an engine failure). It is also likely to get ripped off in an off field landing. If the regs make us carry them around, might as well give it the best chance to work.

The ELT should not be bothered by the GHA15, though at least one brand has been known to false alert in the presence of EMI. YMMV.
 
FWF antennas

I'm a fan of the COMDAT CI 2580-200 antenna (Com/GPS combo) on top of the fuselage, kill 2 birds with one stone and no more antenna blocking or crosstalk from side-side belly mounted antennas. I hate FWF mounted antennas.
Keep xpdr antenna cable run as short as possible.

I’m assuming it’s the temperature that you are concerned about. After doing some research I found these specs for Garmin antenna specs:

Garmin's GA 35 / 36 are manufactured and tested to meet TSO575-93G. The temperature operating limits are -67 F to 185 F ( -55 C to + 85 C) with no significant degradation of performance.

Garmin's GA 37 is manufactured and tested to meet TSO2300-126G. The temperature operating limits are -67 F to 185 F ( -55 C to + 85 C) with no significant degradation of performance.

Based on these I felt FWF in the upper rear section would probably be ok. Also discussed with a number of builders who had done this. To understand temps FWF I have 2 thermocouples connected to my GEA 24 that logs these temps. In flight the antenna tray does not exceed 30 F over ambient. After shutdown the tray does not exceed 45 F over ambient. (Worst case after a prolonged taxi to the ramp). I’ve checked signal strengths cowl on vs cowl off and no degradation and even rotated the plane every 90 degrees to insure no shadowing effect.

Given trade offs in different locations I believe I’m fine with FWF antenna trays.
 
So I just ordered the WAAS and com antenna which will be just aft of cabin top. XME belly just aft FW. I will now be installing ELT inside in baggage area. I am debating placing the GA57X in front windshield or outside in between windshield and FW. Thoughts on GA57X??
 
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