fabricflyer
Well Known Member
Where are most of you placing your Com and Transponder Antennas on the 7A with a slider canopy? Just wondering if I need to wait on riveting at seat floor and baggage floor.
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Com & Transponder antenna locations
- Thread starter fabricflyer
- Start date
tommylewis
Well Known Member
mine
On my RV7a I installed the transponder antenna on the belly in the front right corner. I installed the two comm antennas on the belly, in front of the spar, just inside the gear legs.
On my RV7a I installed the transponder antenna on the belly in the front right corner. I installed the two comm antennas on the belly, in front of the spar, just inside the gear legs.
lostpilot28
Well Known Member
My xpdr antenna (2 inch lollipop) is in the right front corner...just enough room to give it a 2-inch ground plane. Works great.
The comm antenna is under my seat. Again, wanted a ground plane in all directions the same length as the antenna (1/4 wave length). Works great! I was a little worried about a blind spot from the gear legs, but so far that doesn't seem to be a problem.
The comm antenna is under my seat. Again, wanted a ground plane in all directions the same length as the antenna (1/4 wave length). Works great! I was a little worried about a blind spot from the gear legs, but so far that doesn't seem to be a problem.
What kind of range are you getting? The Archer wingtip antennas are (by Bob Archer's words, and most people's experience) very marginal for Comm - maybe 30 miles range due to the wrong polarity. I'm curious if you've discovered better perfomrnace, since you don't have an exterior antenna.
On my -8, I have a belly Comm for #1, Archer tip Comm for #2.
704CH
Well Known Member
Question for those of you who put the Transponder antenna on the front belly near the firewall..
On a tail dragger, what do you think about dead center between the exhaust? This way you could hide the mount under the center tunnel.
I have the 4 pipe exhaust and it will be several inches from it on each side with a good ground plane.
Thoughts?
On a tail dragger, what do you think about dead center between the exhaust? This way you could hide the mount under the center tunnel.
I have the 4 pipe exhaust and it will be several inches from it on each side with a good ground plane.
Thoughts?
RV7Ron
Well Known Member
hmm, a good question that I'm glad you asked...I mistakenly mounted mine in the center, not thinking about the exhaust. I was planning to move it outboard....but will be interested to see if anyone thinks it would be ok to leave it between the exhaust?
lostpilot28
Well Known Member
I would try to keep any antenna away from metal objects on the sides. There is potential that they could block the signal if you're low enough and/or the ATC radar is far enough away.
agirard7a
Well Known Member
Comm location
I am planning my layout for both comm and
Transponder ant. Locations.
A while back I read a thread by Walt Arnow that suggested
that we as builders should strongly consider reading
FAA circular AC 43.13-2b. On page 25 paragraph (d)
It is stated that comm antenna's should be located on top
of the plane and that bent whips are not as effective as straight.
Seems most RV'ers place the coms on the bottom
Any thoughts? I still need to figure this out.
I am planning my layout for both comm and
Transponder ant. Locations.
A while back I read a thread by Walt Arnow that suggested
that we as builders should strongly consider reading
FAA circular AC 43.13-2b. On page 25 paragraph (d)
It is stated that comm antenna's should be located on top
of the plane and that bent whips are not as effective as straight.
Seems most RV'ers place the coms on the bottom
Any thoughts? I still need to figure this out.
agirard7a
Well Known Member
Link
Here is a link to the circular.
http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 43.13-2B.pdf
Here is a link to the circular.
http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 43.13-2B.pdf
Top and bottom?
Considering installing one com antenna on top, and one on the bottom of my RV-7A tip up. Seems that would give the best coverage for both on the ground and in the air (switch radios as necessary)
I installed the single com bent whip antenna for my RV-4 on the bottom. I occasionally get marginal reception on the ground (and in the air less frequently).
My RV-7A will be full IFR, so really good communication is important to me.
Thoughts?
Considering installing one com antenna on top, and one on the bottom of my RV-7A tip up. Seems that would give the best coverage for both on the ground and in the air (switch radios as necessary)
I installed the single com bent whip antenna for my RV-4 on the bottom. I occasionally get marginal reception on the ground (and in the air less frequently).
My RV-7A will be full IFR, so really good communication is important to me.
Thoughts?
Captain Avgas
Well Known Member
Ron, the installation manual for the Garmin GTX 327 transponder calls for the antenna to be at least 36" away from the transponder to avoid interference. The distance from the stack (if it is roughly centred in the panel) to the front centre of the cabin will be significantly less than 36". I suspect that is one of the main reasons that it is not a favored position. Even opting for the front right or front left position will barely produce a 36" distance.
Hey Bobbie, are you worried about all of that radiation right near the family jewels.
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I initially installed the transponder antenna between the exhaust pipes, but had to move it due to poor reception. The folks in the tower let me know about the poor performance. I moved it behind the baggage bulkhead well away from the Comm. antennas that are mounted just below the seats and have had no problems since.
Regards,
Rob
Regards,
Rob
N941WR
Legacy Member
I put my transponder antenna just aft of the firewall and inside of the fuel vent.
You can see it sticking down in this picture. As for dead spots because of the location of the right gear leg, I have had no complaints from ATC.
The single com antenna is under my left leg, in front of the spar. The aft two screws of the bent wip Comant antenna pass through the spar web. The front two screws are on a stiffener on the floor. The BNC connector comes up between the spar and the spar cover.
The best part of this location is that you don't have to pass the cable through the spar.
RV7Ron
Well Known Member
Thanks Bob, didnt know that...looks like I will, indeed, be moving it.
dhall_polo
Well Known Member
These places are very common for RV's. My RV represents at least one case where all these are known good. Other options will work and ymmv.
- Comm: two Comant bent whips on the belly, below seat pans.
- Transponder: "TED" antenna mounted just aft baggage bulkhead.
- VOR: Bob Archer VOR antenna in the wingtip
- GPS and XM Pucks: glare shield.
- Marker Beacon: stripped coax in the wingtip.
- ELT: Behind the canopy frame
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az_gila
Well Known Member
It's interesting that the FAA Taxi Diagram for Tucson (TUS) now states "ALL AIRCRAFT USE UPPER ANTENNA UNTIL AIRBORNE".
http://155.178.201.160/d-tpp/1206/00430AD.PDF
I'm not sure when this note was added....
My transponder lives aft of the baggage compartment, so I put the antenna on the aft belly, it lives all by itself back there so no issues with interference. My ELT antenna is under the tail-cone fairing, Archer-NAV's in the wingtips, the comm antennas (dual bentwhip) are just aft and inside of the gearlegs where a lot of others have put them, and I put a UAT antenna centered under the seats for future ADSB-IN receiver.
As long as I've got a certified WAAS signal for the transponder (which I will, with a 430W in the panel) I don't have to use an ADSB transceiver on the UAT antenna up front, so that UAT will be receive-only for traffic coming back up to me on the 978MHZ band and won't hash my comms.
As long as I've got a certified WAAS signal for the transponder (which I will, with a 430W in the panel) I don't have to use an ADSB transceiver on the UAT antenna up front, so that UAT will be receive-only for traffic coming back up to me on the 978MHZ band and won't hash my comms.
I plan on two COM Antennas
My plan is to place a Bent COM under one of the seats and the other, a straight COM on top of the fuselage. I haven't skined the fuselage top yet, so I was wondering if anyone had any photos of their installation. Also, I have no idea of what the distance back should be from F606 or F607 in order to clear the open slider. Maybe I could install a backer plate during the skin install. I'm running wires now and would like to go ahead and place the antenna cable.
I'm working/planning/trying hard to keep from crawling around in the tail after the skin is on.
Thanks,
My plan is to place a Bent COM under one of the seats and the other, a straight COM on top of the fuselage. I haven't skined the fuselage top yet, so I was wondering if anyone had any photos of their installation. Also, I have no idea of what the distance back should be from F606 or F607 in order to clear the open slider. Maybe I could install a backer plate during the skin install. I'm running wires now and would like to go ahead and place the antenna cable.
I'm working/planning/trying hard to keep from crawling around in the tail after the skin is on.
Thanks,
woodmanrog
Well Known Member
On our present plane our com antenna is a bent whip installed in the center of the fuselage just aft of our seats. The reception is outstanding. At 4K ft we can receive all over the state of Florida. Years ago I put my 2 com antennas inside the gearleg fairings attached to the stiffeners. I was able to receive 50 miles fore and aft and about 30 miles side to side. My antennas in the RV6 were all mounted internally to reduce drag. We gained about 4 knots over the ground at cruise speeds. I was racing at the time but now I like getting reception over hundreds of miles so I keep the antennas where the builder installed them. Oh, I did remove the VOR antenna from the top of the rudder as I thought it looked ugly and I know it caused drag. If I replace it, I will probably put it in the wingtip. Jmtcw
Walt
Well Known Member
I have 2 coms and experimented for a while with one antenna on top. I found no better reception (except on the ground) with the top mounted antenna compared to the bottom mounted antenna. Final locations: one straight antenna under the CP seat and the other a bent whip on the aft fuselage.
Smilin' Jack
Well Known Member
I put the transponder antenna 2 inches inside of the fuel vent and mounted both com antenna's on the underside of the fuselage just aft of the main spar.
It is my experience with even our corporate jets that at some airports on ground control or tower if you don't open the squelch on the comm that has the antenna on the bottom of the aircraft you might not hear them on the ground if your a long ways away from the tower, usually out of site of the tower,Such as DFW.
But in the air the bottom location has a definite advantage on picking up ATIS from airports even when we're 150 NM out from a small airport.
With my eperience that's why I chose the bottom location.
Airports like PDK where you can see the tower from any location on the field the bottom antenna's work fine without having to open up the squelch control on the com
You can view the backing plates I made and the antenna locations on the second Log about picture 350/355
Smilin Jack
It is my experience with even our corporate jets that at some airports on ground control or tower if you don't open the squelch on the comm that has the antenna on the bottom of the aircraft you might not hear them on the ground if your a long ways away from the tower, usually out of site of the tower,Such as DFW.
But in the air the bottom location has a definite advantage on picking up ATIS from airports even when we're 150 NM out from a small airport.
With my eperience that's why I chose the bottom location.
Airports like PDK where you can see the tower from any location on the field the bottom antenna's work fine without having to open up the squelch control on the com
You can view the backing plates I made and the antenna locations on the second Log about picture 350/355
Smilin Jack
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I'm currently doing a panel upgrade and will end up with:
430 with Archer NAV in the wingtip, Comant CI-121 on top, stripped coax glideslope in the lower cowl or gear leg fairing
A210 with existing cheapo bent-whip. This has worked OK for a while, but the transmission has always been terrible on the ground, and I'm at a towered airport (see above for solution)
Existing xpdr antenna in the usual spot on the belly, just after of spar
430W GPS antenna under the cowl
Existing ELT antenna on top, it'll be just aft of the CI-121, I think
430 with Archer NAV in the wingtip, Comant CI-121 on top, stripped coax glideslope in the lower cowl or gear leg fairing
A210 with existing cheapo bent-whip. This has worked OK for a while, but the transmission has always been terrible on the ground, and I'm at a towered airport (see above for solution)
Existing xpdr antenna in the usual spot on the belly, just after of spar
430W GPS antenna under the cowl
Existing ELT antenna on top, it'll be just aft of the CI-121, I think
az_gila
Well Known Member
At Tucson (TUS) it is required that you use the top antenna on the ground.... check the note on the Airport Layout -
http://155.178.201.160/d-tpp/1213/00430AD.PDF
Do any other airports have the same FAA note?
I ended up putting my 406Mhz ELT antenna on top, behind the GPS puck for my 300XL and ahead of the vertical stab. I don't think you could fit another comm antenna up there without being too close to the ELT antenna.
Something to consider if you are installing a newer ELT which has stricter antenna placement requirements.
Something to consider if you are installing a newer ELT which has stricter antenna placement requirements.
